# List of asteroid close approaches to Earth in 2021

Below is the list of asteroids that have come close to Earth in 2021.

## Timeline of known close approaches less than one lunar distance from Earth

A list of known near-Earth asteroid close approaches less than 1 lunar distance (0.0025696 AU (384,410 km; 238,860 mi)) from Earth in 2021, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS).
For reference, the radius of Earth is about 0.0000426 AU (6,370 km; 3,960 mi) or 0.0166 lunar distances. Geosynchronous satellites have an orbit with semi-major axis length of 0.000282 AU (42,200 km; 26,200 mi) or 0.110 lunar distances.
The largest asteroid to pass within 1 LD of Earth in 2021 was 2021 SG with an estimated diameter of around 68 meters and an absolute magnitude of 24.0. The fastest asteroid to pass within 1 LD of Earth in 2021 was 2021 UA$_7$ that passed Earth with a velocity with respect to Earth of 27.7 km/s (62,000 mph).
The CNEOS database of close approaches lists some close approaches a full orbit or more before the discovery of the object, derived by orbit calculation. The list below only includes close approaches that are evidenced by observations, thus the pre-discovery close approaches would only be included if the object was found by precovery, but there was no such close approach in 2021.
This list and the relevant databases do not consider impacts as close approaches, thus this list does not include any of the objects that collided with Earth's atmosphere in 2021, none of which were discovered in advance, but were observed visually or recorded by sensors designed to detect detonation of nuclear devices.
Rows highlighted red indicate objects which were not discovered until after closest approach
Rows highlighted yellow indicate objects discovered less than 24 hours before closest approach
Rows highlighted green indicate objects discovered more than one week before closest approach
Rows highlighted turquoise indicate objects discovered more than 7 weeks before closest approach
Rows highlighted blue indicate objects discovered more than one year before closest approach (i.e. objects successfully cataloged on a previous orbit, rather than being detected during final approach)
| Date of closest approach | Discovery | Object | Nominal geocentric distance | Nominal geocentric distance | Approx. size (m) | (H) (abs. mag.) | Closer approach to Moon |
| Date of closest approach | Discovery | Object | (AU) | (Lunar distance) | Approx. size (m) | (H) (abs. mag.) | Closer approach to Moon |
| 2021-01-01 | 2021-01-02 G96 Mt. Lemmon Survey | 2021 AA | 0.00159 AU (238,000 km; 148,000 mi) | 0.617 | 11–24 | 27.0 | — |
| 2021-01-03 | 2021-01-03 703 Catalina Sky Survey | 2021 AH | 0.000333 AU (49,800 km; 31,000 mi) | 0.130 | 5.3–12 | 28.5 | — |
| 2021-01-04 | 2021-01-05 G96 Mt. Lemmon Survey | 2021 AH$_8$ | 0.000354 AU (53,000 km; 32,900 mi) | 0.138 | 3.2–7.2 | 29.6 | — |
| 2021-01-09 | 2021-01-08 G96 Mt. Lemmon Survey | 2021 AS$_2$ | 0.000718 AU (107,400 km; 66,700 mi) | 0.279 | 3.2–7.2 | 29.6 | — |
| 2021-01-16 | 2021-01-18 G96 Mt. Lemmon Survey | 2021 BR$_2$ | 0.000492 AU (73,600 km; 45,700 mi) | 0.192 | 1.8–4.0 | 30.9 | — |
| 2021-01-18 | 2021-01-17 G96 Mt. Lemmon Survey | 2021 BK | 0.000751 AU (112,300 km; 69,800 mi) | 0.292 | 2.3–5.2 | 30.3 | — |
| 2021-01-18 | 2021-01-17 703 Catalina Sky Survey | 2021 BV$_1$ | 0.00161 AU (241,000 km; 150,000 mi) | 0.625 | 6.6–15 | 28.0 | — |
| 2021-01-18 | 2021-01-17 G96 Mt. Lemmon Survey | 2021 BO | 0.000160 AU (23,900 km; 14,900 mi) | 0.062 | 0.68–1.5 | 33.0 | — |
| 2021-01-20 | 2021-01-18 G96 Mt. Lemmon Survey | 2021 BO$_1$ | 0.00168 AU (251,000 km; 156,000 mi) | 0.653 | 3.8–8.6 | 29.2 | — |
| 2021-01-26 | 2018-01-18 | 2018 BA$_3$ | 0.00250 AU (374,000 km; 232,000 mi) | 0.974 | 14–31 | 26.4 | — |
| 2021-02-04 | 2021-02-05 703 Catalina Sky Survey | 2021 CV | 0.00135 AU (202,000 km; 125,000 mi) | 0.525 | 4.4–9.9 | 28.9 | — |
| 2021-02-09 | 2021-02-09 I41 Palomar Mountain—ZTF | 2021 CZ$_3$ | 0.000152 AU (22,700 km; 14,100 mi) | 0.059 | 1.7–3.8 | 31.0 | — |
| 2021-02-11 | 2021-02-05 703 Catalina Sky Survey | 2021 CO | 0.00242 AU (362,000 km; 225,000 mi) | 0.942 | 24–55 | 25.2 | — |
| 2021-02-11 | 2021-02-11 703 Catalina Sky Survey | 2021 CQ$_5$ | 0.00119 AU (178,000 km; 111,000 mi) | 0.461 | 5.1–11 | 28.6 | — |
| 2021-02-12 | 2021-02-11 V00 Kitt Peak-Bok | 2021 CC$_6$ | 0.00113 AU (169,000 km; 105,000 mi) | 0.439 | 2.5–5.5 | 30.1 | — |
| 2021-02-12 | 2021-02-12 381 Tokyo-Kiso | 2021 CC$_7$ | 0.00217 AU (325,000 km; 202,000 mi) | 0.844 | 3.0–6.7 | 29.7 | — |
| 2021-02-13 | 2021-02-10 F51 Pan-STARRS 1, Haleakala | 2021 CA$_6$ | 0.00111 AU (166,000 km; 103,000 mi) | 0.431 | 5.2–12 | 28.6 | — |
| 2021-02-14 | 2021-02-12 T08 ATLAS-MLO, Mauna Loa | 2021 CS$_6$ | 0.00100 AU (150,000 km; 93,000 mi) | 0.391 | 7.3–16 | 27.8 | — |
| 2021-02-14 | 2021-02-13 K88 GINOP-KHK, Piszkesteto | 2021 CW$_7$ | 0.000187 AU (28,000 km; 17,400 mi) | 0.073 | 1.5–3.4 | 31.2 | — |
| 2021-02-18 | 2021-02-18 I41 Palomar Mountain—ZTF | 2021 DN$_1$ | 0.00226 AU (338,000 km; 210,000 mi) | 0.878 | 6.3–14 | 28.1 | — |
| 2021-02-18 | 2021-02-17 G96 Mt. Lemmon Survey | 2021 DG | 0.00111 AU (166,000 km; 103,000 mi) | 0.431 | 2.2–4.9 | 30.4 | — |
| 2021-02-21 | 2021-02-22 K88 GINOP-KHK, Piszkesteto | 2021 DA$_2$ | 0.00132 AU (197,000 km; 123,000 mi) | 0.512 | 3.9–8.7 | 29.2 | — |
| 2021-03-02 | 2021-03-01 K88 GINOP-KHK, Piszkesteto | 2021 EA | 0.000627 AU (93,800 km; 58,300 mi) | 0.244 | 6.3–14 | 28.1 | — |
| 2021-03-08 | 2021-03-06 G96 Mt. Lemmon Survey | 2021 EF$_1$ | 0.00187 AU (280,000 km; 174,000 mi) | 0.729 | 3.1–6.8 | 29.7 | ✓ |
| 2021-03-09 | 2021-03-10 G96 Mt. Lemmon Survey | 2021 EG$_3$ | 0.000981 AU (146,800 km; 91,200 mi) | 0.382 | 3.8–8.6 | 29.2 | — |
| 2021-03-15 | 2021-03-15 T08 ATLAS-MLO, Mauna Loa | 2021 EN$_4$ | 0.000473 AU (70,800 km; 44,000 mi) | 0.184 | 3.1–6.9 | 29.7 | — |
| 2021-03-15 | 2021-03-15 381 Tokyo-Kiso | 2021 EP$_4$ | 0.00248 AU (371,000 km; 231,000 mi) | 0.967 | 3.7–8.4 | 29.3 | — |
| 2021-03-16 | 2021-03-11 G96 Mt. Lemmon Survey | 2021 EQ$_3$ | 0.00186 AU (278,000 km; 173,000 mi) | 0.724 | 16–36 | 26.1 | ✓ |
| 2021-03-20 | 2021-03-22 G96 Mt. Lemmon Survey | 2021 FM$_2$ | 0.000559 AU (83,600 km; 52,000 mi) | 0.218 | 2.3–5.2 | 30.3 | — |
| 2021-03-21 | 2021-03-22 G96 Mt. Lemmon Survey | 2021 FF$_2$ | 0.00213 AU (319,000 km; 198,000 mi) | 0.829 | 6.3–14 | 28.1 | — |
| 2021-03-23 | 2021-03-20 G96 Mt. Lemmon Survey | 2021 FO$_1$ | 0.00215 AU (322,000 km; 200,000 mi) | 0.836 | 3.4–7.6 | 29.5 | — |
| 2021-03-23 | 2021-03-18 G96 Mt. Lemmon Survey | 2021 FH | 0.00157 AU (235,000 km; 146,000 mi) | 0.612 | 12–27 | 26.8 | — |
| 2021-03-23 | 2021-03-22 G96 Mt. Lemmon Survey | 2021 FP$_2$ | 0.00216 AU (323,000 km; 201,000 mi) | 0.841 | 2.5–5.6 | 30.1 | — |
| 2021-04-03 | 2021-04-04 G96 Mt. Lemmon Survey | 2021 GE$_2$ | 0.00161 AU (241,000 km; 150,000 mi) | 0.625 | 3.9–8.8 | 29.1 | — |
| 2021-04-04 | 2021-04-03 G96 Mt. Lemmon Survey | 2021 GV | 0.00224 AU (335,000 km; 208,000 mi) | 0.872 | 3.8–8.6 | 29.2 | — |
| 2021-04-05 | 2021-04-03 G96 Mt. Lemmon Survey | 2021 GS | 0.00167 AU (250,000 km; 155,000 mi) | 0.649 | 4.8–11 | 28.7 | — |
| 2021-04-05 | 2021-04-05 I41 Palomar Mountain—ZTF | 2021 GZ$_7$ | 0.00126 AU (188,000 km; 117,000 mi) | 0.492 | 4.3–9.6 | 28.9 | ✓ |
| 2021-04-08 | 2021-04-08 381 Tokyo-Kiso | 2021 GV$_4$ | 0.00212 AU (317,000 km; 197,000 mi) | 0.824 | 4.3–9.6 | 29.0 | — |
| 2021-04-09 | 2021-04-11 T08 ATLAS-MLO, Mauna Loa | 2021 GL$_{16}$ | 0.00247 AU (370,000 km; 230,000 mi) | 0.959 | 15–33 | 26.3 | ✓ |
| 2021-04-10 | 2021-04-06 F51 Pan-STARRS 1, Haleakala | 2021 GT$_3$ | 0.00171 AU (256,000 km; 159,000 mi) | 0.665 | 14–32 | 26.4 | — |
| 2021-04-10 | 2021-04-10 381 Tokyo-Kiso | 2021 GE$_{226}$ (ex TMG0042) | 0.00220 AU (329,000 km; 205,000 mi) | 0.855 | 5.5–12 | 28.4 | — |
| 2021-04-11 | 2021-04-10 703 Catalina Sky Survey | 2021 GQ$_5$ | 0.00248 AU (371,000 km; 231,000 mi) | 0.966 | 5.3–12 | 28.5 | — |
| 2021-04-11 | 2021-04-11 381 Tokyo-Kiso | 2021 GA$_{168}$ | 0.00156 AU (233,000 km; 145,000 mi) | 0.608 | 4.5–10 | 28.9 | — |
| 2021-04-12 | 2021-04-08 G96 Mt. Lemmon Survey | 2021 GW4 | 0.000175 AU (26,200 km; 16,300 mi) | 0.068 | 3.4–7.6 | 29.5 | — |
| 2021-04-13 | 2021-04-13 I41 Palomar Mountain—ZTF | 2021 GC$_{13}$ | 0.00228 AU (341,000 km; 212,000 mi) | 0.888 | 4.0–8.9 | 29.1 | — |
| 2021-04-13 | 2021-04-11 V00 Kitt Peak-Bok | 2021 GC$_8$ | 0.00146 AU (218,000 km; 136,000 mi) | 0.567 | 2.0–4.5 | 30.6 | — |
| 2021-04-14 | 2021-04-14 381 Tokyo-Kiso | 2021 GQ$_{10}$ | 0.00116 AU (174,000 km; 108,000 mi) | 0.453 | 13–28 | 26.6 | — |
| 2021-04-14 | 2021-04-15 T08 ATLAS-MLO, Mauna Loa | 2021 GW$_{16}$ | 0.000195 AU (29,200 km; 18,100 mi) | 0.076 | 2.5–5.7 | 30.1 | — |
| 2021-04-15 | 2021-04-17 T05 ATLAS-HKO, Haleakala | 2021 HC$_1$ | 0.00155 AU (232,000 km; 144,000 mi) | 0.601 | 6.8–15 | 28.0 | ✓ |
| 2021-04-15 | 2021-04-14 W94 MAP, San Pedro de Atacama | 2021 GF$_{10}$ | 0.000774 AU (115,800 km; 71,900 mi) | 0.301 | 6.2–14 | 28.2 | — |
| 2021-04-15 | 2021-04-14 F51 Pan-STARRS 1, Haleakala | 2021 GN$_{10}$ | 0.00192 AU (287,000 km; 178,000 mi) | 0.748 | 5.6–12 | 28.4 | ✓ |
| 2021-04-17 | 2021-04-18 703 Catalina Sky Survey | 2021 HE$_1$ | 0.00153 AU (229,000 km; 142,000 mi) | 0.594 | 4.4–9.7 | 28.9 | ✓ |
| 2021-04-19 | 2021-04-17 G96 Mt. Lemmon Survey | 2021 HN | 0.00170 AU (254,000 km; 158,000 mi) | 0.661 | 11–25 | 26.9 | — |
| 2021-04-23 | 2021-04-23 P07 Space Surveillance Telescope, HEH Station | 2021 HE$_{41}$ | 0.00251 AU (375,000 km; 233,000 mi) | 0.977 | 4.7–11 | 28.8 | ? |
| 2021-05-02 | 2021-05-03 T05 ATLAS-HKO, Haleakala | 2021 JW | 0.00173 AU (259,000 km; 161,000 mi) | 0.675 | 8.0–18 | 27.6 | — |
| 2021-05-04 | 2021-05-03 T05 ATLAS-HKO, Haleakala | 2021 JV | 0.000936 AU (140,000 km; 87,000 mi) | 0.364 | 8.6–19 | 27.4 | — |
| 2021-05-06 | 2021-05-05 G96 Mt. Lemmon Survey | 2021 JS$_1$ | 0.000739 AU (110,600 km; 68,700 mi) | 0.288 | 5.3–12 | 28.5 | — |
| 2021-05-08 | 2021-05-07 G96 Mt. Lemmon Survey | 2021 JQ$_2$ | 0.000449 AU (67,200 km; 41,700 mi) | 0.175 | 2.6–5.9 | 30.0 | — |
| 2021-05-13 | 2021-05-08 F51 Pan-STARRS 1, Haleakala | 2021 JB$_6$ | 0.000706 AU (105,600 km; 65,600 mi) | 0.275 | 4.7–10 | 28.8 | — |
| 2021-05-14 | 2021-05-14 I41 Palomar Mountain—ZTF | 2021 JU$_6$ | 0.000442 AU (66,100 km; 41,100 mi) | 0.172 | 10–23 | 27.1 | — |
| 2021-05-15 | 2021-05-15 P07 Space Surveillance Telescope, HEH Station | 2021 JH$_{83}$ | 0.00104 AU (156,000 km; 97,000 mi) | 0.403 | 0.85–1.9 | 32.5 | ? |
| 2021-05-16 | 2021-05-16 P07 Space Surveillance Telescope, HEH Station | 2021 KQ$_{22}$ | 0.00203 AU (304,000 km; 189,000 mi) | 0.789 | 1.0–2.3 | 32.0 | ? |
| 2021-05-27 | 2021-06-01 F51 Pan-STARRS 1, Haleakala | 2021 LV | 0.00188 AU (281,000 km; 175,000 mi) | 0.730 | 6.9–15 | 27.9 | ✓ |
| 2021-05-30 | 2021-05-30 381 Tokyo-Kiso | 2021 KO$_2$ | 0.00248 AU (371,000 km; 231,000 mi) | 0.964 | 6.6–15 | 28.0 | — |
| 2021-05-30 | 2021-05-30 381 Tokyo-Kiso | 2021 KB$_{22}$ (ex TMG0049) | 0.000726 AU (108,600 km; 67,500 mi) | 0.282 | 2.7–6.0 | 30.0 | — |
| 2021-05-31 | 2021-05-30 381 Tokyo-Kiso | 2021 KN$_2$ | 0.000966 AU (144,500 km; 89,800 mi) | 0.376 | 5.0–11 | 28.6 | — |
| 2021-05-31 | 2021-05-31 381 Tokyo-Kiso | 2021 KQ$_2$ | 0.00119 AU (178,000 km; 111,000 mi) | 0.461 | 2.7–6.1 | 30.0 | — |
| 2021-06-01 | 2021-05-31 G96 Mt. Lemmon Survey | 2021 KT$_2$ | 0.00195 AU (292,000 km; 181,000 mi) | 0.758 | 5.6–12 | 28.4 | — |
| 2021-06-04 | 2021-06-05 T05 ATLAS-HKO, Haleakala | 2021 LX$_1$ | 0.00107 AU (160,000 km; 99,000 mi) | 0.415 | 10–23 | 27.1 | — |
| 2021-06-12 | 2021-06-11 F51 Pan-STARRS 1, Haleakala | 2021 LG$_5$ | 0.00106 AU (159,000 km; 99,000 mi) | 0.41 | 4.8–11 | 28.7 | — |
| 2021-06-13 | 2021-06-08 G96 Mt. Lemmon Survey | 2021 LO$_2$ | 0.00148 AU (221,000 km; 138,000 mi) | 0.58 | 6.6–15 | 28.0 | — |
| 2021-06-15 | 2021-06-18 W94 MAP, San Pedro de Atacama | 2021 MU | 0.00111 AU (166,000 km; 103,000 mi) | 0.43 | 8.8–20 | 27.4 | — |
| 2021-06-17 | 2021-06-17 T05 ATLAS-HKO, Haleakala | 2021 ME | 0.00212 AU (317,000 km; 197,000 mi) | 0.824 | 4.3–9.6 | 29.0 | — |
| 2021-07-03 | 2021-07-01 F51 Pan-STARRS 1, Haleakala | 2021 NA | 0.000436 AU (65,200 km; 40,500 mi) | 0.170 | 5.2–12 | 28.6 | — |
| 2021-07-08 | 2021-07-09 F51 Pan-STARRS 1, Haleakala | 2021 NU$_3$ | 0.00120 AU (180,000 km; 112,000 mi) | 0.465 | 5.0–11 | 28.6 | — |
| 2021-07-20 | 2021-07-19 W94 MAP, San Pedro de Atacama | 2021 OV | 0.00131 AU (196,000 km; 122,000 mi) | 0.510 | 7.5–17 | 27.8 | ✓ |
| 2021-07-31 | 2021-07-30 T08 ATLAS-MLO, Mauna Loa | 2021 OD$_1$ | 0.00170 AU (254,000 km; 158,000 mi) | 0.662 | 5.9–13 | 28.3 | — |
| 2021-08-02 | 2021-08-02 I41 Palomar Mountain—ZTF | 2021 PC | 0.00110 AU (165,000 km; 102,000 mi) | 0.427 | 12–27 | 26.7 | — |
| 2021-08-02 | 2021-08-02 T08 ATLAS-MLO | 2021 PL$_{132}$ | 0.00233 AU (349,000 km; 217,000 mi) | 0.905 | 6.1–14 | 28.2 | — |
| 2021-08-05 | 2021-08-07 F51 Pan-STARRS 1, Haleakala | 2021 PY$_4$ | 0.00188 AU (281,000 km; 175,000 mi) | 0.731 | 13–29 | 26.5 | — |
| 2021-08-06 | 2021-08-08 W94 MAP, San Pedro de Atacama | 2021 PK$_4$ | 0.00160 AU (239,000 km; 149,000 mi) | 0.622 | 6.1–14 | 28.2 | — |
| 2021-08-14 | 2021-08-15 T05 ATLAS-HKO, Haleakala | 2021 PA$_{17}$ | 0.000447 AU (66,900 km; 41,600 mi) | 0.174 | 7.3–16 | 27.8 | — |
| 2021-08-27 | 2021-08-27 T05 ATLAS-HKO, Haleakala | 2021 QD$_1$ | 0.00204 AU (305,000 km; 190,000 mi) | 0.796 | 4.8–11 | 28.7 | — |
| 2021-08-28 | 2021-08-30 F51 Pan-STARRS 1, Haleakala | 2021 QV$_3$ | 0.000854 AU (127,800 km; 79,400 mi) | 0.332 | 2.4–5.3 | 30.2 | — |
| 2021-09-02 | 2021-09-03 I41 Palomar Mountain—ZTF | 2021 RN$_5$ | 0.00253 AU (378,000 km; 235,000 mi) | 0.985 | 8.1–18 | 27.6 | ✓ |
| 2021-09-02 | 2021-09-05 K88 GINOP-KHK, Piszkesteto | 2021 RD$_{239}$ | 0.00147 AU (220,000 km; 137,000 mi) | 0.570 | 5.6–12 | 28.4 | ? |
| 2021-09-06 | 2021-09-08 F51 Pan-STARRS 1, Haleakala | 2021 RT$_4$ | 0.00177 AU (265,000 km; 165,000 mi) | 0.689 | 6.2–14 | 28.2 | — |
| 2021-09-07 | 2021-09-08 F51 Pan-STARRS 1, Haleakala | 2021 RS$_{100}$ | 0.00128 AU (191,000 km; 119,000 mi) | 0.498 | 4.7–11 | 28.8 | ✓ |
| 2021-09-08 | 2021-09-07 G96 Mt. Lemmon Survey | 2021 RS$_2$ | 0.000145 AU (21,700 km; 13,500 mi) | 0.056 | 2.3–5.1 | 30.4 | — |
| 2021-09-08 | 2021-09-07 703 Catalina Sky Survey | 2021 RP$_2$ | 0.000802 AU (120,000 km; 74,600 mi) | 0.312 | 2.3–5.2 | 30.3 | ✓ |
| 2021-09-08 | 2021-09-09 K88 GINOP-KHK, Piszkesteto | 2021 RS$_5$ | 0.000921 AU (137,800 km; 85,600 mi) | 0.358 | 5.7–13 | 28.4 | — |
| 2021-09-09 | 2021-09-05 T05 ATLAS-HKO, Haleakala | 2021 RQ$_2$ | 0.00126 AU (188,000 km; 117,000 mi) | 0.489 | 3.3–7.3 | 29.5 | — |
| 2021-09-09 | 2021-09-10 703 Catalina Sky Survey | 2021 RB$_6$ | 0.00172 AU (257,000 km; 160,000 mi) | 0.671 | 6.6–15 | 28.0 | — |
| 2021-09-11 | 2021-09-10 T05 ATLAS-HKO, Haleakala | 2021 RG$_6$ | 0.000569 AU (85,100 km; 52,900 mi) | 0.221 | 4.4–9.8 | 28.9 | — |
| 2021-09-11 | 2021-09-12 T08 ATLAS-MLO, Mauna Loa | 2021 RG$_{12}$ | 0.00217 AU (325,000 km; 202,000 mi) | 0.843 | 3.9–8.7 | 29.2 | — |
| 2021-09-12 | 2021-09-08 G96 Mt. Lemmon Survey | 2021 RR$_5$ | 0.000527 AU (78,800 km; 49,000 mi) | 0.205 | 5.6–12 | 28.4 | — |
| 2021-09-16 | 2021-09-13 F51 Pan-STARRS 1, Haleakala | 2021 RF$_{16}$ | 0.00213 AU (319,000 km; 198,000 mi) | 0.829 | 4.3–9.6 | 29.0 | — |
| 2021-09-16 | 2021-09-17 I41 Palomar Mountain—ZTF | 2021 SG | 0.00164 AU (245,000 km; 152,000 mi) | 0.637 | 42–94 | 24.0 | — |
| 2021-09-17 | 2021-09-17 I41 Palomar Mountain—ZTF | 2021 SP | 0.0000943 AU (14,110 km; 8,770 mi) | 0.037 | 3.7–8.4 | 29.3 | — |
| 2021-09-20 | 2021-09-23 F51 Pan-STARRS 1, Haleakala | 2021 SQ | 0.00184 AU (275,000 km; 171,000 mi) | 0.717 | 5.5–12 | 28.4 | ✓ |
| 2021-09-26 | 2021-09-28 F52 Pan-STARRS 2, Haleakala | 2021 SW$_1$ | 0.00182 AU (272,000 km; 169,000 mi) | 0.707 | 2.9–6.5 | 29.8 | — |
| 2021-09-27 | 2021-09-28 T05 ATLAS-HKO, Haleakala | 2021 SQ$_1$ | 0.00111 AU (166,000 km; 103,000 mi) | 0.432 | 4.6–10 | 28.8 | — |
| 2021-09-30 | 2021-10-02 G96 Mt. Lemmon Survey | 2021 TT | 0.000886 AU (132,500 km; 82,400 mi) | 0.345 | 6.9–15 | 27.9 | — |
| 2021-10-01 | 2021-10-02 F52 Pan-STARRS 2, Haleakala | 2021 TX | 0.000283 AU (42,300 km; 26,300 mi) | 0.110 | 1.5–3.5 | 31.2 | — |
| 2021-10-03 | 2021-10-03 T08 ATLAS-MLO, Mauna Loa | 2021 TV$_1$ | 0.00108 AU (162,000 km; 100,000 mi) | 0.419 | 6.1–14 | 28.2 | — |
| 2021-10-03 | 2021-10-03 G96 Mt. Lemmon Survey | 2021 TG$_1$ | 0.00196 AU (293,000 km; 182,000 mi) | 0.762 | 6.1–14 | 28.2 | — |
| 2021-10-06 | 2021-10-06 381 Tokyo-Kiso | 2021 TQ$_4$ | 0.00255 AU (381,000 km; 237,000 mi) | 0.992 | 2.7–6.1 | 29.9 | — |
| 2021-10-10 | 2021-10-03 F52 Pan-STARRS 2, Haleakala | 2021 TT$_1$ | 0.00251 AU (375,000 km; 233,000 mi) | 0.975 | 15–34 | 26.2 | ✓ |
| 2021-10-11 | 2021-10-11 T05 ATLAS-HKO, Haleakala | 2021 TK$_{11}$ | 0.000909 AU (136,000 km; 84,500 mi) | 0.354 | 5.2–12 | 28.6 | — |
| 2021-10-11 | 2021-10-11 T05 ATLAS-HKO, Haleakala | 2021 TT$_{13}$ | 0.000358 AU (53,600 km; 33,300 mi) | 0.139 | 3.1–6.8 | 29.7 | — |
| 2021-10-11 | 2021-10-13 F51 Pan-STARRS 1, Haleakala | 2021 TH$_{15}$ | 0.00211 AU (316,000 km; 196,000 mi) | 0.819 | 4.5–10 | 28.9 | ✓ |
| 2021-10-12 | 2021-10-13 G96 Mt. Lemmon Survey | 2021 TE$_{13}$ | 0.000180 AU (26,900 km; 16,700 mi) | 0.070 | 3.6–8.0 | 29.4 | — |
| 2021-10-14 | 2021-10-14 T05 ATLAS-HKO, Haleakala | 2021 TM$_{14}$ | 0.000980 AU (146,600 km; 91,100 mi) | 0.381 | 6.7–15 | 28.0 | — |
| 2021-10-16 | 2021-10-16 703 Catalina Sky Survey | 2021 UL | 0.000241 AU (36,100 km; 22,400 mi) | 0.094 | 2.3–5.2 | 30.3 | ✓ |
| 2021-10-16 | 2021-10-14 G96 Mt. Lemmon Survey | 2021 TJ$_{15}$ | 0.00257 AU (384,000 km; 239,000 mi) | 1.000 | 5.5–12 | 28.4 | — |
| 2021-10-17 | 2021-10-17 P07 Space Surveillance Telescope, HEH Station | 2021 UR$_{132}$ | 0.00161 AU (241,000 km; 150,000 mi) | 0.626 | 6.1–14 | 28.2 | ? |
| 2021-10-18 | 2021-10-11 F51 Pan-STARRS 1, Haleakala | 2021 TG$_{14}$ | 0.00167 AU (250,000 km; 155,000 mi) | 0.650 | 6.1–14 | 28.2 | — |
| 2021-10-24 | 2021-10-24 K88 GINOP-KHK, Piszkesteto | 2021 UT | 0.00100 AU (150,000 km; 93,000 mi) | 0.39 | 3.7–8.2 | 29.3 | — |
| 2021-10-25 | 2021-10-26 G96 Mt. Lemmon Survey | 2021 UO$_1$ | 0.00102 AU (153,000 km; 95,000 mi) | 0.40 | 6.6–15 | 28.0 | — |
| 2021-10-25 | 2021-10-25 703 Catalina Sky Survey | 2021 UA1 | 0.0000630 AU (9,420 km; 5,860 mi) | 0.025 | 1.1–2.5 | 31.8 | — |
| 2021-10-27 | 2021-10-28 G96 Mt. Lemmon Survey | 2021 UA$_7$ | 0.000857 AU (128,200 km; 79,700 mi) | 0.333 | 4.7–11 | 28.8 | — |
| 2021-10-27 | 2021-10-26 G96 Mt. Lemmon Survey | 2021 UH$_1$ | 0.000480 AU (71,800 km; 44,600 mi) | 0.187 | 1.2–2.8 | 31.7 | — |
| 2021-10-29 | 2021-10-30 W94 MAP, San Pedro de Atacama | 2021 UV$_5$ | 0.000774 AU (115,800 km; 71,900 mi) | 0.301 | 4.6–10 | 28.8 | — |
| 2021-10-29 | 2021-10-31 K88 GINOP-KHK, Piszkesteto | 2021 UT$_5$ | 0.00205 AU (307,000 km; 191,000 mi) | 0.797 | 5.7–13 | 28.4 | — |
| 2021-10-29 | 2021-10-29 381 Tokyo-Kiso | 2021 UF$_{12}$ | 0.00161 AU (241,000 km; 150,000 mi) | 0.628 | 3.7–8.2 | 29.3 | — |
| 2021-10-29 | 2021-10-29 P07 Space Surveillance Telescope, HEH Station | 2021 UP$_{120}$ | 0.000404 AU (60,400 km; 37,600 mi) | 0.157 | 0.83–1.9 | 32.5 | ? |
| 2021-10-30 | 2021-10-30 P07 Space Surveillance Telescope, HEH Station | 2021 UO$_{120}$ | 0.00109 AU (163,000 km; 101,000 mi) | 0.423 | 1.2–2.6 | 31.8 | ? |
| 2021-10-30 | 2021-10-27 G96 Mt. Lemmon Survey | 2021 UW$_1$ | 0.00256 AU (383,000 km; 238,000 mi) | 0.995 | 16–35 | 26.2 | — |
| 2021-10-30 | 2021-10-31 T08 ATLAS-MLO, Mauna Loa | 2021 UJ$_6$ | 0.00232 AU (347,000 km; 216,000 mi) | 0.901 | 6.0–13 | 28.3 | — |
| 2021-11-01 | 2021-11-02 T08 ATLAS-MLO, Mauna Loa | 2021 VH | 0.000196 AU (29,300 km; 18,200 mi) | 0.076 | 3.2–7.0 | 29.6 | — |
| 2021-11-01 | 2021-10-29 P07 Space Surveillance Telescope, HEH Station | 2021 VK$_{96}$ | 0.00245 AU (367,000 km; 228,000 mi) | 0.955 | 2.2–4.9 | 30.4 | ? |
| 2021-11-04 | 2021-11-04 P07 Space Surveillance Telescope, HEH Station | 2021 VL$_{96}$ | 0.00206 AU (308,000 km; 191,000 mi) | 0.802 | 2.4–5.3 | 30.3 | ? |
| 2021-11-04 | 2021-10-31 F51 Pan-STARRS 1, Haleakala | 2021 UO$_7$ | 0.00247 AU (370,000 km; 230,000 mi) | 0.963 | 3.3–7.3 | 29.6 | — |
| 2021-11-07 | 2021-11-11 G96 Mt. Lemmon Survey | 2021 VS$_{11}$ | 0.00204 AU (305,000 km; 190,000 mi) | 0.792 | 4.8–11 | 28.7 | — |
| 2021-11-07 | 2021-11-06 G96 Mt. Lemmon Survey | 2021 VK$_3$ | 0.000567 AU (84,800 km; 52,700 mi) | 0.221 | 2.2–4.8 | 30.5 | — |
| 2021-11-08 | 2021-11-07 T08 ATLAS-MLO, Mauna Loa | 2021 VL$_3$ | 0.00111 AU (166,000 km; 103,000 mi) | 0.433 | 5.4–12 | 28.5 | — |
| 2021-11-08 | 2021-11-07 G96 Mt. Lemmon Survey | 2021 VN$_3$ | 0.000919 AU (137,500 km; 85,400 mi) | 0.358 | 2.0–4.5 | 30.6 | — |
| 2021-11-08 | 2021-11-07 G96 Mt. Lemmon Survey | 2021 VM$_3$ | 0.00204 AU (305,000 km; 190,000 mi) | 0.793 | 2.8–6.3 | 29.9 | — |
| 2021-11-09 | 2021-11-10 G96 Mt. Lemmon Survey | 2021 VD$_8$ | 0.000831 AU (124,300 km; 77,200 mi) | 0.324 | 2.2–5.0 | 30.4 | — |
| 2021-11-09 | 2021-11-09 G96 Mt. Lemmon Survey | 2021 VP$_{11}$ | 0.000385 AU (57,600 km; 35,800 mi) | 0.150 | 1.2–2.6 | 31.8 | — |
| 2021-11-09 | 2021-11-09 P07 Space Surveillance Telescope, HEH Station | 2021 VM$_{96}$ | 0.00168 AU (251,000 km; 156,000 mi) | 0.656 | 1.0–2.3 | 32.0 | ? |
| 2021-11-10 | 2021-11-08 F52 Pan-STARRS 2, Haleakala | 2021 VU$_4$ | 0.000724 AU (108,300 km; 67,300 mi) | 0.282 | 5.5–12 | 28.4 | — |
| 2021-11-11 | 2021-11-10 G96 Mt. Lemmon Survey | 2021 VY$_7$ | 0.00214 AU (320,000 km; 199,000 mi) | 0.832 | 3.5–7.9 | 29.4 | — |
| 2021-11-12 | 2021-11-10 G96 Mt. Lemmon Survey | 2021 VC$_7$ | 0.00124 AU (186,000 km; 115,000 mi) | 0.481 | 5.8–13 | 28.3 | — |
| 2021-11-21 | 2021-11-24 T08 ATLAS-MLO, Mauna Loa | 2021 WP | 0.00104 AU (156,000 km; 97,000 mi) | 0.405 | 7.1–16 | 27.9 | — |
| 2021-11-26 | 2021-11-27 703 Catalina Sky Survey | 2021 WA$_1$ | 0.00206 AU (308,000 km; 191,000 mi) | 0.802 | 7.7–17 | 27.7 | ✓ |
| 2021-11-28 | 2021-11-27 G96 Mt. Lemmon Survey | 2021 WC$_1$ | 0.00136 AU (203,000 km; 126,000 mi) | 0.530 | 5.3–12 | 28.5 | — |
| 2021-11-30 | 2021-12-02 G96 Mt. Lemmon Survey | 2021 XV | 0.000991 AU (148,300 km; 92,100 mi) | 0.386 | 2.5–5.7 | 30.1 | — |
| 2021-12-01 | 2021-11-29 G96 Mt. Lemmon Survey | 2021 WF$_3$ | 0.000959 AU (143,500 km; 89,100 mi) | 0.373 | 3.5–7.8 | 29.4 | — |
| 2021-12-01 | 2021-12-02 I41 Palomar Mountain—ZTF | 2021 XL | 0.00135 AU (202,000 km; 125,000 mi) | 0.526 | 4.6–10 | 28.8 | — |
| 2021-12-04 | 2021-12-02 G96 Mt. Lemmon Survey | 2021 XF$_1$ | 0.00206 AU (308,000 km; 191,000 mi) | 0.803 | 3.3–7.3 | 29.5 | — |
| 2021-12-05 | 2021-12-03 G96 Mt. Lemmon Survey | 2021 XC$_2$ | 0.00212 AU (317,000 km; 197,000 mi) | 0.823 | 3.0–6.6 | 29.8 | — |
| 2021-12-09 | 2021-12-12 G96 Mt. Lemmon Survey | 2021 XZ$_5$ | 0.00214 AU (320,000 km; 199,000 mi) | 0.834 | 5.8–13 | 28.3 | ✓ |
| 2021-12-09 | 2021-12-08 G96 Mt. Lemmon Survey | 2021 XU$_5$ | 0.00160 AU (239,000 km; 149,000 mi) | 0.623 | 3.5–7.8 | 29.4 | ✓ |
| 2021-12-10 | 2021-12-08 G96 Mt. Lemmon Survey | 2021 XV$_4$ | 0.00120 AU (180,000 km; 112,000 mi) | 0.467 | 5.0–11 | 28.6 | — |
| 2021-12-11 | 2021-12-08 G96 Mt. Lemmon Survey | 2021 XX$_4$ | 0.00251 AU (375,000 km; 233,000 mi) | 0.977 | 5.1–11 | 28.6 | — |
| 2021-12-11 | 2021-12-11 381 Tokyo-Kiso | 2021 XA$_{11}$ | 0.000617 AU (92,300 km; 57,400 mi) | 0.240 | 5.8–13 | 28.3 | — |
| 2021-12-16 | 2021-12-12 G96 Mt. Lemmon Survey | 2021 XC$_6$ | 0.00140 AU (209,000 km; 130,000 mi) | 0.544 | 5.8–13 | 28.3 | ✓ |
| Date of closest approach | Discovery | Object | Nominal geocentric distance | Nominal geocentric distance | Approx. size (m) | (H) (abs. mag.) | Closer approach to Moon |
| Date of closest approach | Discovery | Object | (AU) | ( Lunar distance) | Approx. size (m) | (H) (abs. mag.) | Closer approach to Moon |
| 2021-03-01 | 2021-03-02 | ZTF0KfF | 0.00187 AU (280,000 km; 174,000 mi) | 0.73 | 0.96–5.9 | 31.0 | ? |
| 2021-03-07 | 2021-03-06 | C4YK182 | 0.000632 AU (94,500 km; 58,700 mi) | 0.25 | 1.8–5.9 | 30.3 | — |
| 2021-03-10 | 2021-03-11 | ScKo07a | 0.0013 AU (190,000 km; 120,000 mi) | 0.51 | 0.97–5.9 | 31.0 | — |
| 2021-03-23 | 2021-03-23 | B03SK22 | 0.00019 AU (28,000 km; 18,000 mi) | 0.074 | 0.38–2.4 | 33.0 | — |
| 2021-04-01 | 2021-04-01 | A10w8qG | 0.00149 AU (223,000 km; 139,000 mi) | 0.58 | 3.2–12 | 28.9 | ✓ |
| 2021-04-03 | 2021-04-06 | P11ekJ0 | 0.00188 AU (281,000 km; 175,000 mi) | 0.73 | 2.9–18 | 28.6 | — |
| 2021-04-06 | 2021-04-07 | P11eyxx | 0.00024 AU (36,000 km; 22,000 mi) | 0.093 | 1.4–5.4 | 30.7 | — |
| 2021-04-08 | 2021-04-07 | A10wiOp | 0.00224 AU (335,000 km; 208,000 mi) | 0.87 | 2.8–17 | 28.7 | — |
| 2021-04-11 | 2021-04-11 | TMG0044 | 0.00126 AU (188,000 km; 117,000 mi) | 0.49 | 2.5–9.9 | 29.4 | — |
| 2021-04-11 | 2021-04-07 | P11exfR | 0.00244 AU (365,000 km; 227,000 mi) | 0.95 | 3.1–19 | 28.5 | — |
| 2021-04-11 | 2021-04-11 | TMG0045 | 0.00156 AU (233,000 km; 145,000 mi) | 0.61 | 3.7–12 | 28.8 | — |
| 2021-04-13 | 2021-04-13 | ZTF0KwS | 0.00105 AU (157,000 km; 98,000 mi) | 0.41 | 2.4–15 | 29.0 | ? |
| 2021-04-16 | 2021-04-17 | ZTF0KyD | 0.00213 AU (319,000 km; 198,000 mi) | 0.83 | 3.2–20 | 28.4 | ? |
| 2021-04-17 | 2021-04-14 | P11f7ua | 0.00108 AU (162,000 km; 100,000 mi) | 0.42 | 2.9–9.4 | 29.3 | — |
| 2021-04-17 | 2021-04-17 | B04SK17 | 0.00106 AU (159,000 km; 99,000 mi) | 0.41 | 3.1–30 | 28.0 | ? |
| 2021-04-23 | 2021-04-25 | A10wMMp | 0.000735 AU (110,000 km; 68,300 mi) | 0.29 | 2.5–16 | 28.9 | ? |
| 2021-04-24 | 2021-04-24 | ZTF0Kzz | 0.0016 AU (240,000 km; 150,000 mi) | 0.62 | 1.2–7.5 | 30.5 | ? |
| 2021-05-02 | 2021-05-02 | S514008 | 0.00079 AU (118,000 km; 73,000 mi) | 0.31 | 2.4–15 | 29.0 | ? |
| 2021-05-07 | 2021-05-09 | P11gae7 | 0.00126 AU (188,000 km; 117,000 mi) | 0.49 | 3.1–19 | 28.5 | — |
| 2021-05-08 | 2021-05-09 | P11gae5 | 0.00057 AU (85,000 km; 53,000 mi) | 0.22 | 1.3–8.2 | 30.3 | — |
| 2021-05-09 | 2021-05-12 | P11ggM3 | 0.00235 AU (352,000 km; 218,000 mi) | 0.91 | 1.2–7.5 | 30.5 | — |
| 2021-05-31 | 2021-05-31 | C5Q2Z32 | 0.0000774 AU (11,580 km; 7,190 mi) | 0.030 | 0.67–4.1 | 31.8 | — |

### Warning times by size

This sub-section visualises the warning times of the close approaches listed in the table of confirmed close approaches, depending on the size of the asteroid. It shows the effectiveness of asteroid warning systems at detecting close approaches in 2021. The sizes of the charts show the relative sizes of the asteroids to scale. For comparison, the approximate size of a person is also shown. This is based the absolute magnitude of each asteroid, an approximate measure of size based on brightness.
Absolute magnitude H ≥ 30 (smallest)
(size of a person for comparison)
Absolute magnitude 30 > H ≥ 29
Absolute magnitude 29 > H ≥ 28
Absolute magnitude 28 > H ≥ 27
Absolute magnitude 27 > H ≥ 26 (probable size of the Chelyabinsk meteor)
Absolute magnitude 26 > H ≥ 25
Absolute magnitude 25 > H (largest)
* After closest approach: 1 (100.0%)
* < 24 hours before: 0 (0.0%)
* up to 7 days before: 0 (0.0%)
* > one week before: 0 (0.0%)
* > 7 weeks before: 0 (0.0%)
* > one year before: 0 (0.0%)

### Predicted close approaches

Below is the list of predicted close approaches of near-Earth asteroids larger than magnitude 27, that were predicted to occur in 2021. This relates to the effectiveness of asteroid cataloging systems at predicting close approaches in 2021. 2018 BA$_3$ (with a 9 day observation arc from January 2018) could have passed as far as 3 million km (8 LD) from Earth.
For asteroids which were observed but not predicted in advance, see the main list above.
Rows highlighted orange indicate objects which were predicted theoretically but were not observed in practice
Rows highlighted yellow indicate objects which were predicted and observed but the predicted close approach date and distance were incorrect
Rows highlighted green indicate objects which were observed with the predicted close approach distance (within +/-50%) but wrong date
Rows highlighted turquoise indicate objects which were observed with the predicted close approach date but wrong distance (out by over 50%)
Rows highlighted blue indicate objects which were observed as predicted with the correct close approach date and distance
| Object | Predicted Date of closest approach | Actual Date of closest approach | Predicted closest approach range (Lunar distance) | Actual closest approach distance (Lunar distance) | (H) (abs. mag) | Approx. Size (m) |
| 2018 BA$_3$ | 2021-01-26 ±7 days | Not observed in 2021 | 0.74–8.2 (0.97 nominal) | Not observed in 2021 | 26.4 | 14–31 |