Datasets:

usgrowzones
/

us-zip-hardiness-zone-changes

city stringlengths 4 16	state stringclasses 51 values	census_geoid int64 103k 5.61M	lat float64 21.3 64.8	lon float64 -157.85 -70.17	elev_m float64 -1.5 2.08k	usda_zone_2023 stringclasses 17 values	station_id stringlengths 11 11	station_name stringlengths 8 33	distance_km float64 0.2 27.6	elev_diff_m float64 -145 140	years int64 10 30	status stringclasses 2 values	last10 stringlengths 5 5 ⌀	last30 stringlengths 5 5 ⌀	last50 stringlengths 5 5 ⌀	first10 stringclasses 99 values	first30 stringlengths 5 5 ⌀	first50 stringlengths 5 5 ⌀	gsl50 float64 105 365
New York	NY	3,651,000	40.662712	-73.938677	16.6	7b	USC00305796	NY AVE V BROOKLYN, NY	8.4	-11	16	dates	04/12	04/04	04/01	11/06	11/13	11/19	233
Los Angeles	CA	644,000	34.019394	-118.410825	25	10a	USC00042214	CULVER CITY, CA	1.6	3	21	rare	null	null	null	null	null	null	365
Chicago	IL	1,714,000	41.837045	-87.684939	180.9	6a	USC00111550	CHICAGO NORTHERLY IS, IL	6.6	-3	15	dates	04/25	04/17	04/10	10/24	11/01	11/05	208
Houston	TX	4,835,000	29.785743	-95.388806	15.9	9b	USC00414326	HOUSTON-PORT, TX	11.4	-10	14	dates	03/05	02/18	02/02	11/27	12/08	12/25	327
Phoenix	AZ	455,000	33.572154	-112.090132	378.6	9b	USW00003184	PHOENIX DEER VALLEY MUNI AP, AZ	12.9	65	21	dates	02/12	01/23	01/08	12/05	12/15	12/25	354
Philadelphia	PA	4,260,000	40.009376	-75.133346	30.6	7b	USC00366886	PHILA FRANKLIN INST, PA	6.6	-12	25	dates	04/12	04/04	03/30	11/04	11/11	11/17	232
San Antonio	TX	4,865,000	29.462809	-98.524635	219.9	9a	USC00417947	SAN ANTONIO INCARNATE WORD, TX	5.1	-6	16	dates	03/19	03/05	02/25	11/07	11/18	11/28	277
San Diego	CA	666,000	32.814977	-117.135562	128.1	10b	USW00003131	SAN DIEGO MONTGOMERY FLD, CA	0.4	-1	20	rare	null	null	null	null	null	null	365
Dallas	TX	4,819,000	32.793333	-96.766513	147.1	8b	USW00013960	DALLAS LOVE FLD, TX	10.6	-13	29	dates	03/19	03/09	03/02	11/10	11/20	11/29	272
Jacksonville	FL	1,235,000	30.336864	-81.661603	1.2	9b	USW00093837	JACKSONVILLE NAS, FL	11.5	5	23	dates	03/03	02/15	02/01	12/03	12/24	01/05	330
Fort Worth	TX	4,827,000	32.781954	-97.348573	168.2	8b	USW00093904	FT WORTH MEACHAM FLD NAAF, TX	3.9	47	11	dates	03/25	03/12	03/05	11/03	11/14	11/24	264
San Jose	CA	668,000	37.296011	-121.814552	49.7	9b	USC00047821	SAN JOSE, CA	9.9	-29	17	dates	01/23	01/10	01/02	12/04	12/14	12/25	362
Austin	TX	4,805,000	30.298622	-97.754134	186	9a	USW00013958	AUSTIN-CAMP MABRY, TX	2.5	18	30	dates	03/14	03/02	02/20	11/15	11/26	12/03	291
Charlotte	NC	3,712,000	35.209045	-80.83099	205.6	8a	USW00013881	CHARLOTTE DOUGLAS AP, NC	11.4	16	28	dates	04/14	04/05	03/30	10/22	10/30	11/03	221
Columbus	OH	3,918,000	39.983938	-82.984882	245.8	6b	USC00331785	COLUMBUS WCMH, OH	5.8	-20	10	dates	05/07	04/27	04/20	10/13	10/20	10/24	185
Indianapolis	IN	1,836,003	39.776664	-86.145935	219.1	6b	USC00124272	INDIANAPOLIS SE SIDE, IN	9.5	39	23	dates	05/05	04/26	04/20	10/07	10/16	10/21	183
San Francisco	CA	667,000	37.7793	-122.4193	18.5	10b	USW00023272	SAN FRANCISCO DWTN, CA	1.2	27	29	rare	null	null	null	null	null	null	365
Seattle	WA	5,363,000	47.619335	-122.351538	44	9a	USW00094290	SEATTLE SAND PT WSFO, WA	10.4	-26	29	dates	03/29	03/16	03/08	11/04	11/15	11/23	259
Denver	CO	820,000	39.76185	-104.881105	1,613.1	6a	USW00023062	DENVER-STAPLETON, CO	1	-2	28	dates	05/16	05/08	05/04	09/25	10/03	10/08	156
Oklahoma City	OK	4,055,000	35.467079	-97.513657	364.6	7b	USW00013967	OKLAHOMA CITY WILL ROGERS AP, OK	11.7	27	29	dates	04/20	04/10	04/04	10/21	10/29	11/02	213
Nashville	TN	4,752,006	36.1718	-86.785002	130.1	7b	USC00408238	SHELBY BOTTOMS NATURE, TN	5.5	-7	11	dates	04/16	04/07	04/01	10/18	10/25	10/31	213
Washington	DC	1,150,000	38.904247	-77.016517	16.9	7b	USC00186350	NATL ARBORETUM DC, MD	4.1	-2	29	dates	04/11	04/03	03/29	10/26	11/02	11/08	224
El Paso	TX	4,824,000	31.84778	-106.431106	1,186	8b	USW00023044	EL PASO INTL AP, TX	6.6	8	28	dates	03/19	03/09	03/02	11/06	11/14	11/20	261
Las Vegas	NV	3,240,000	36.233499	-115.264037	716.5	9a	USW00053123	LAS VEGAS AIR TERMINAL, NV	6.6	-45	19	dates	02/19	02/04	01/24	11/24	12/04	12/10	323
Boston	MA	2,507,000	42.338551	-71.018253	1.5	6b	USW00014739	BOSTON LOGAN INTL AP, MA	2.5	2	28	dates	04/17	04/08	04/04	10/29	11/03	11/09	218
Detroit	MI	2,622,000	42.383037	-83.102237	194.6	6b	USC00202016	DEARBORN #2, MI	7.1	-10	14	dates	05/11	05/02	04/27	10/10	10/20	10/25	181
Louisville	KY	2,148,006	38.165376	-85.647377	158.5	7a	USC00154958	LOUISVILLE WFO, KY	5.6	34	24	dates	04/23	04/13	04/06	10/21	10/29	11/01	209
Portland	OR	4,159,000	45.536951	-122.649971	49.1	9a	USC00356749	PORTLAND KGW-TV, OR	3.7	-1	24	dates	03/21	03/06	02/25	11/10	11/22	12/01	280
Memphis	TN	4,748,000	35.109164	-89.968511	95.8	8a	USW00013893	MEMPHIS INTL AP, TN	6.1	-18	30	dates	04/04	03/24	03/16	11/02	11/09	11/16	244
Baltimore	MD	2,404,000	39.300032	-76.610476	11.8	7b	USW00093784	MD SCI CTR BALTIMORE, MD	2.1	-6	19	dates	04/04	03/29	03/24	11/07	11/15	11/21	244
Milwaukee	WI	5,553,000	43.063348	-87.966695	216.4	6a	USC00475474	MT MARY COLLEGE, WI	5.2	2	28	dates	05/12	05/02	04/26	10/02	10/12	10/18	173
Albuquerque	NM	3,502,000	35.10478	-106.646809	1,512.7	7b	USC00296754	PETROGLYPH NATL MON, NM	7	48	22	dates	04/30	04/21	04/15	10/16	10/22	10/27	193
Tucson	AZ	477,000	32.153036	-110.870773	822.3	9a	USW00023160	TUCSON INTL AP, AZ	8.3	-45	29	dates	03/02	02/17	02/05	11/21	11/30	12/09	307
Fresno	CA	627,000	36.782684	-119.793359	94.8	9b	USW00093193	FRESNO YOSEMITE INTL AP, CA	6.6	7	30	dates	02/11	01/29	01/14	11/29	12/06	12/14	337
Sacramento	CA	664,000	38.567694	-121.468161	8.1	9b	USW00023271	SACRAMENTO 5 ESE, CA	4.7	4	30	dates	02/08	01/22	01/12	11/28	12/07	12/16	341
Atlanta	GA	1,304,000	33.762909	-84.422675	291.4	8a	USW00003888	ATLANTA FULTON CO AP, GA	9.3	-35	22	dates	04/10	03/31	03/24	10/27	11/01	11/08	231
Mesa	AZ	446,000	33.400626	-111.716487	404.8	9b	USC00022782	E MESA, AZ	7	58	15	dates	02/28	02/12	02/01	11/22	12/02	12/10	312
Kansas City	MO	2,938,000	39.125155	-94.550313	226	6b	USW00013988	KANSAS CITY DOWNTOWN AP, MO	4	0	29	dates	04/20	04/10	04/04	10/21	10/29	11/02	211
Raleigh	NC	3,755,000	35.831868	-78.641042	94.6	8a	USC00317079	RALEIGH STATE UNIV, NC	6.9	27	27	dates	04/12	04/03	03/28	10/28	11/04	11/08	229
Colorado Springs	CO	816,000	38.867255	-104.760749	1,931.7	6a	USW00093037	COLORADO SPRINGS MUNI AP, CO	8.9	-48	30	dates	05/15	05/08	05/03	09/26	10/03	10/08	158
Omaha	NE	3,137,000	41.262705	-96.053475	354.6	6a	USW00094918	OMAHA #1, NE	10.4	36	11	dates	05/06	04/25	04/16	10/02	10/12	10/18	183
Miami	FL	1,245,000	25.775163	-80.208615	2	11a	USW00092811	MIAMI BEACH, FL	8.3	-2	24	rare	null	null	null	null	null	null	365
Virginia Beach	VA	5,182,000	36.779525	-76.029142	3.9	8b	USW00013769	OCEANA NAS, VA	4.2	3	20	dates	04/11	04/03	03/29	11/01	11/07	11/12	230
Long Beach	CA	643,000	33.780791	-118.16818	10.3	10b	USW00023129	LONG BEACH DAUGHERTY FLD, CA	4	-1	23	rare	null	null	null	null	null	null	365
Oakland	CA	653,000	37.769846	-122.22569	5.1	10a	USC00046336	OAKLAND MUSEUM, CA	4.6	4	24	rare	null	null	null	null	null	null	365
Minneapolis	MN	2,743,000	44.963324	-93.26832	264	5a	USC00214884	LOWER ST ANTHONY FALLS, MN	2.4	-34	25	dates	05/07	04/30	04/23	10/02	10/10	10/16	175
Bakersfield	CA	603,526	35.353171	-119.037919	116.8	9b	USC00040444	BAKERSFIELD 5 NW, CA	7.4	27	14	dates	02/27	02/12	01/31	11/23	12/01	12/08	312
Tulsa	OK	4,075,000	36.127949	-95.902316	221.1	7b	USW00013968	TULSA INTL AP, OK	8.1	-23	29	dates	04/15	04/05	03/31	10/20	10/30	11/04	220
Tampa	FL	1,271,000	27.970086	-82.479673	1.1	10a	USW00012842	TAMPA INTL AP, FL	6	5	28	dates	02/10	01/31	01/20	12/23	01/03	01/12	365
Arlington	TX	4,804,000	32.700708	-97.124691	199.2	8b	USW00053907	ARLINGTON MUNI AP, TX	5	-7	18	dates	03/28	03/16	03/09	11/03	11/12	11/21	256
Aurora	CO	804,000	39.709537	-104.720509	1,690	6a	USC00051547	CHERRY CREEK DAM, CO	13.3	31	13	dates	05/21	05/12	05/07	09/25	10/02	10/08	152
Wichita	KS	2,079,000	37.690638	-97.345836	395	7a	USC00148847	WICHITA WX, KS	9.4	12	11	dates	04/25	04/16	04/08	10/11	10/21	10/27	200
Cleveland	OH	3,916,000	41.478462	-81.679435	192.3	7a	USW00004853	CLEVELAND BURKE AP, OH	4.4	-14	20	dates	04/20	04/14	04/08	11/01	11/07	11/12	217
New Orleans	LA	2,255,000	30.05342	-89.934502	-1.5	9b	USW00053917	NEW ORLEANS LAKEFRONT AP, LA	9.1	4	21	dates	02/23	02/01	01/22	12/13	12/29	01/05	348
Henderson	NV	3,231,900	36.008958	-115.0268	794	9b	USC00264439	LAS VEGAS WFO, NV	14.8	-101	22	dates	02/27	02/14	02/04	11/19	11/28	12/05	302
Honolulu	HI	1,571,550	21.324347	-157.84764	52	12b	USC00519397	WAIKIKI 717.2, HI	6.7	-49	18	rare	null	null	null	null	null	null	365
Anaheim	CA	602,000	33.855502	-117.758657	187.4	10b	USC00040192	ANAHEIM, CA	7.8	-116	24	rare	null	null	null	null	null	null	365
Orlando	FL	1,253,000	28.40865	-81.254805	24.2	10a	USW00012815	ORLANDO INTL AP, FL	7.4	3	28	dates	02/26	02/04	01/25	12/18	01/01	01/10	355
Lexington	KY	2,146,027	38.040678	-84.458272	322.9	7a	USW00093820	LEXINGTON BLUEGRASS AP, KY	12.9	-24	30	dates	05/01	04/20	04/13	10/16	10/23	10/28	196
Stockton	CA	675,000	37.976553	-121.308598	3.4	9b	USC00048560	STOCKTON FIRE STN 4, CA	2.7	0	15	dates	03/11	02/19	02/05	11/17	11/28	12/08	305
Riverside	CA	662,000	33.938143	-117.393168	271.7	10a	USC00047470	RIVERSIDE FIRE STN 3, CA	1.5	-16	21	dates	02/25	01/25	01/09	12/01	12/15	12/25	353
Irvine	CA	636,770	33.678399	-117.771254	43.4	10b	USC00049087	TUSTIN IRVINE RCH, CA	3.1	28	13	dates	02/02	01/14	01/05	12/03	12/13	12/25	365
Corpus Christi	TX	4,817,000	27.754252	-97.173385	0.5	10a	USW00012926	CORPUS CHRISTI NAS, TX	13.4	5	23	dates	02/20	01/31	01/14	12/18	01/01	01/08	365
Newark	NJ	3,451,000	40.72422	-74.172574	3.7	7b	USC00283704	HARRISON, NJ	3.2	4	15	dates	04/16	04/08	04/04	10/25	11/01	11/06	216
Santa Ana	CA	669,000	33.736332	-117.8829	23.5	10b	USC00047888	SANTA ANA FIRE STN, CA	1.7	18	28	rare	null	null	null	null	null	null	365
Cincinnati	OH	3,915,000	39.140183	-84.505829	231.9	6b	USC00331515	CHEVIOT, OH	10.3	40	26	dates	05/05	04/24	04/17	10/11	10/21	10/26	191
Pittsburgh	PA	4,261,000	40.439936	-79.975676	295.4	6b	USW00014762	PITTSBURGH ALLEGHENY CO AP, PA	10.5	85	22	dates	05/06	04/24	04/18	10/14	10/22	10/28	193
St. Paul	MN	2,758,000	44.948901	-93.104063	256.8	5a	USC00217379	ST PAUL 3SW, MN	4.4	25	11	dates	05/09	05/01	04/25	10/01	10/07	10/12	169
Greensboro	NC	3,728,000	36.09485	-79.823624	250.8	8a	USC00313625	GREENSBORO WTP, NC	2.2	-18	11	dates	04/14	04/05	04/01	10/23	10/31	11/04	217
Jersey City	NJ	3,436,000	40.711417	-74.06476	6.9	7b	USC00283704	HARRISON, NJ	8.4	0	15	dates	04/16	04/08	04/04	10/25	11/01	11/06	216
Durham	NC	3,719,000	35.977928	-78.898109	106.1	8a	USC00312515	DURHAM, NC	9.2	16	16	dates	04/18	04/09	04/02	10/24	11/01	11/04	217
Lincoln	NE	3,128,000	40.810284	-96.674856	375.4	6a	USW00014939	LINCOLN MUNI AP, NE	7.6	-13	30	dates	05/07	04/30	04/24	09/29	10/07	10/13	171
North Las Vegas	NV	3,251,800	36.289865	-115.089181	643.6	9b	USC00265705	N LAS VEGAS, NV	6.6	-65	23	dates	02/24	02/11	02/01	11/23	12/01	12/08	311
Plano	TX	4,858,016	33.050769	-96.747944	217	8b	USC00417588	RICHARDSON, TX	6.1	-10	11	dates	03/29	03/14	03/07	11/02	11/13	11/21	259
Anchorage	AK	203,000	61.2181	-149.9003	31.6	5a	USW00026409	ANCHORAGE MERRILL FLD, AK	2.4	10	23	dates	05/09	05/04	05/01	09/17	09/24	09/29	150
Gilbert	AZ	427,400	33.310345	-111.743121	390	9b	USC00021514	CHANDLER HEIGHTS, AZ	12.9	44	14	dates	02/27	02/12	02/01	11/23	12/03	12/11	315
Madison	WI	5,548,000	43.087815	-89.429856	281.7	5b	USC00470273	UW ARBORETUM - MADISON, WI	5.2	-16	27	dates	05/17	05/07	05/01	09/26	10/03	10/09	161
Reno	NV	3,260,600	39.549097	-119.849907	1,502.7	7b	USC00266791	RENO WFO, NV	5.1	17	23	dates	05/19	05/06	04/28	10/10	10/21	10/27	182
Chandler	AZ	412,000	33.282765	-111.851819	367.9	9b	USC00028499	TEMPE ASU, AZ	17.2	-12	24	dates	03/09	02/24	02/13	11/18	11/29	12/05	298
St. Louis	MO	2,965,000	38.635699	-90.244582	142.3	7a	USC00237452	ST LOUIS SCI CTR, MO	2.3	15	25	dates	04/18	04/07	04/01	10/24	10/31	11/04	218
Chula Vista	CA	613,392	32.62767	-117.01517	133.4	10b	USW00003178	SAN DIEGO BROWN FLD, CA	7	24	23	dates	02/05	01/17	01/06	12/11	12/22	12/31	365
Buffalo	NY	3,611,000	42.892492	-78.859686	186.4	6b	USW00014733	BUFFALO, NY	11.8	25	29	dates	05/09	04/30	04/24	10/10	10/19	10/26	183
Fort Wayne	IN	1,825,000	41.088193	-85.142791	231.2	6a	USW00014827	FT WAYNE INTL AP, IN	14.1	10	30	dates	05/10	05/01	04/24	10/08	10/16	10/21	178
Lubbock	TX	4,845,000	33.561901	-101.888883	985.8	7b	USW00023042	LUBBOCK, TX	12.4	8	29	dates	04/22	04/12	04/04	10/19	10/28	11/02	210
St. Petersburg	FL	1,263,000	27.762727	-82.644131	11.1	10b	USC00087886	ST PETERSBURG, FL	1.8	-9	22	dates	02/05	01/28	01/17	12/23	01/07	01/15	365
Toledo	OH	3,977,000	41.664071	-83.581861	185.7	6b	USW00004848	TOLEDO METCALF FLD, OH	14.2	4	19	dates	05/07	04/27	04/20	10/14	10/22	10/27	188
Laredo	TX	4,841,464	27.560379	-99.489181	147.3	9b	USC00415060	LAREDO 2, TX	1.3	-16	26	dates	02/25	02/05	01/25	11/23	12/06	12/17	329
Port St. Lucie	FL	1,258,715	27.280554	-80.388261	7.1	10a	USC00088620	STUART, FL	17.8	-3	26	dates	02/10	01/30	01/23	01/01	01/10	01/18	365
Glendale	AZ	427,820	33.533111	-112.189901	348.2	9b	USC00029634	YOUNGTOWN, AZ	12.4	-2	29	dates	02/18	02/02	01/20	11/28	12/08	12/15	331
Irving	TX	4,837,000	32.857748	-96.970022	170.3	8b	USW00003927	DALLAS FT WORTH AP, TX	6.4	0	26	dates	03/26	03/15	03/08	11/06	11/15	11/24	262
Winston-Salem	NC	3,775,000	36.102863	-80.260829	242	8a	USW00093807	WINSTON SALEM RYNLDS AP, NC	4.9	54	21	dates	04/11	04/02	03/26	10/28	11/03	11/09	228
Chesapeake	VA	5,116,000	36.679376	-76.301788	4.2	8a	USW00013762	FENTRESS NAAS, VA	14.9	1	11	dates	04/07	03/29	03/23	11/04	11/12	11/18	240
Garland	TX	4,829,000	32.909826	-96.630334	160.8	8b	USC00417588	RICHARDSON, TX	14.2	46	11	dates	03/29	03/14	03/07	11/02	11/13	11/21	259
Scottsdale	AZ	465,000	33.684272	-111.861448	712.9	10a	USC00026603	PINNACLE PEAK, AZ	4.8	69	16	dates	03/05	02/13	01/27	11/28	12/11	12/21	330
Boise	ID	1,608,830	43.599335	-116.229817	835.6	7a	USW00024131	BOISE AIR TERMINAL, ID	3.7	22	27	dates	05/09	04/30	04/24	10/05	10/14	10/21	179
Hialeah	FL	1,230,000	25.869941	-80.302865	2.1	11a	USW00012882	MIAMI OPA LOCKA AP, FL	4.7	1	22	rare	null	null	null	null	null	null	365
Frisco	TX	4,827,684	33.155427	-96.822596	214.4	8b	USC00417588	RICHARDSON, TX	19.2	-8	11	dates	03/29	03/14	03/07	11/02	11/13	11/21	259
Richmond	VA	5,167,000	37.531399	-77.476009	22.3	7b	USW00013740	RICHMOND INTL AP, VA	14	28	29	dates	04/18	04/09	04/03	10/23	10/31	11/04	215
Cape Coral	FL	1,210,275	26.643192	-81.997364	3.7	10b	USW00012835	FT MYERS PAGE FLD AP, FL	15	1	28	dates	02/02	01/28	01/16	12/31	01/07	01/13	365
Norfolk	VA	5,157,000	36.923015	-76.244641	4.2	8b	USW00013750	NORFOLK NAS, VA	4.6	1	24	dates	04/01	03/23	03/16	11/08	11/18	11/26	255

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U.S. ZIP Code Plant Hardiness Zone Changes (2012 → 2023) and City Frost Dates

Compiled by US Grow Zones (https://usgrowzones.com). Version 1.0, October 2026.

Not the official USDA Plant Hardiness Zone Map. This is an independent, derived tabulation. It is not affiliated with or endorsed by USDA-ARS, Oregon State University (PRISM Group), NOAA, or the U.S. Census Bureau. For official zones see https://planthardiness.ars.usda.gov/.

Files

zip_hardiness_zone_change_2012_2023.csv (41,142 rows)

column	meaning
zip	5-digit ZIP code as listed by PRISM/OSU
region	US (contiguous), AK, HI, PR — the PRISM listing file the ZIP came from
zone_2012	half-zone in the 2012 USDA PHZM ZIP listing (blank if ZIP not listed in 2012)
zone_2023	half-zone in the 2023 USDA PHZM ZIP listing (blank if ZIP not listed in 2023)
half_zone_change	2023 minus 2012, in half-zones (+1 = one half-zone warmer, i.e. +5 °F in the average annual extreme minimum temperature class)
change	warmer / colder / same; blank if either year is missing

Summary of ZIPs listed in both years: 23,109 warmer, 16,927 same, 444 colder.

city_frost_dates_512.csv (512 rows)

Frost-date estimates for 512 U.S. cities as published on usgrowzones.com.

column	meaning
city, state, census_geoid	Census place name, state, place GEOID
lat, lon	place internal point (Census Gazetteer)
elev_m	place elevation (USGS EPQS / 3DEP)
usda_zone_2023	dominant 2023 zone of the city's ZIPs (by land share)
station_id, station_name	NOAA GHCN station used
distance_km, elev_diff_m	station distance from city point; station minus city elevation
years	years of record reported in the normals
status	`dates` = normal frost dates; `rare` = 32 °F occurs in < 50% of years
last10/last30/last50	spring last-32 °F date (MM/DD) with 10/30/50% probability of a later frost
first10/first30/first50	fall first-32 °F date with 10/30/50% probability of an earlier frost
gsl50	growing-season length (days) at 50% probability

Methodology

Zone change: joined the PRISM/OSU 2012 and 2023 ZIP listings on ZIP code; zones converted to half-zone integers and differenced. ZIP listings reflect each ZIP's representative point; ZIP boundaries changed between years, so single-ZIP changes can partly reflect geography, not climate. The 2023 map also uses a different period (1991–2020 vs 1976–2005) and more stations; USDA notes that changes are not solely evidence of climate change.
Frost dates: for each city, nearest NOAA 1991–2020 normals station with |elevation difference| ≤ 150 m within 25 km; radius then elevation limit relaxed stepwise if none; stations with < 10 years of record used only as last resort. No weighting by station type.

Sources and attribution

USDA Plant Hardiness Zone Map, 2012 and 2023. Agricultural Research Service, U.S. Department of Agriculture. https://planthardiness.ars.usda.gov/ — ZIP listings from PRISM Group, Oregon State University, https://prism.oregonstate.edu/phzm/, accessed Oct 2026. OSU retains ownership; data may be freely reproduced and redistributed with attribution, and altered/derived data must carry the "not the official USDA map" disclaimer (above). Terms: https://prism.oregonstate.edu/terms/ and https://planthardiness.ars.usda.gov/pages/map-creation
NOAA NCEI U.S. Climate Normals 1991–2020 (frost/freeze probability normals). U.S. Government work, public domain in the U.S. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals
U.S. Census Bureau: 2024 Gazetteer files, Vintage 2024 population estimates, 2020 ZCTA-to-place relationship file. U.S. Government work, public domain.
USGS Elevation Point Query Service (3DEP). U.S. Government work, public domain.

Citation

Tang, Damon (2026). U.S. ZIP Code Plant Hardiness Zone Changes (2012 → 2023) and City Frost Dates (v1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.23661628

License

CC BY 4.0 for the compilation and derived columns — see LICENSE (source data remain under their own terms).

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