# The Arboretum at Flagstaff

The Arboretum at Flagstaff is a 200-acre (81 ha) arboretum that is home to 750 species of mostly drought-tolerant adapted and native plants representative of the high-desert Colorado Plateau, home to the Grand Canyon and Zion National Park. It is located 3.8 miles (6.1 km) south of U.S. Route 66 on Woody Mountain Road, on the west side of Flagstaff, Arizona, US. The facility is located at 7,150' in elevation, making it one of the highest-elevation public gardens in the United States. The Arboretum has an extensive regional collection of the Penstemon genus and hosts an annual Penstemon Festival.
The Arboretum was originally forest and a working ranch, and the home of Frances McAllister in the late 1960s. She donated the land and created its financial endowment for the Arboretum in 1981. To support research the Arboretum is also home to the Merriam-Powell Research Station and Southwest Experimental Garden Array.

## Climate

Flagstaff 4 SW is a weather station near The Arboretum. Flagstaff 4 SW has a dry-summer humid continental climate (Köppen Dsb) and is within the 5b USDA Hardiness Zone, with an average annual extreme minimum temperature of -13.8 °F (25.4 °C).
Climate data for Flagstaff 4 SW, Arizona, 1991–2020 normals, 1984-2020 extremes: 7125ft (2172m) :
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 63 (17) | 70 (21) | 73 (23) | 80 (27) | 87 (31) | 94 (34) | 96 (36) | 93 (34) | 91 (33) | 81 (27) | 73 (23) | 66 (19) | 96 (36) |
| Mean maximum °F (°C) | 56.7 (13.7) | 58.7 (14.8) | 64.8 (18.2) | 71.8 (22.1) | 78.9 (26.1) | 87.6 (30.9) | 90.1 (32.3) | 86.8 (30.4) | 82.4 (28.0) | 75.7 (24.3) | 66.5 (19.2) | 58.6 (14.8) | 91.0 (32.8) |
| Mean daily maximum °F (°C) | 43.9 (6.6) | 45.8 (7.7) | 51.9 (11.1) | 58.6 (14.8) | 67.2 (19.6) | 78.0 (25.6) | 81.6 (27.6) | 78.9 (26.1) | 73.8 (23.2) | 63.8 (17.7) | 52.6 (11.4) | 43.6 (6.4) | 61.6 (16.5) |
| Daily mean °F (°C) | 28.4 (−2.0) | 31.0 (−0.6) | 36.2 (2.3) | 41.9 (5.5) | 48.6 (9.2) | 57.3 (14.1) | 64.2 (17.9) | 62.8 (17.1) | 56.1 (13.4) | 45.9 (7.7) | 35.7 (2.1) | 28.1 (−2.2) | 44.7 (7.0) |
| Mean daily minimum °F (°C) | 12.9 (−10.6) | 16.1 (−8.8) | 20.5 (−6.4) | 25.2 (−3.8) | 30.1 (−1.1) | 36.5 (2.5) | 46.9 (8.3) | 46.6 (8.1) | 38.4 (3.6) | 27.9 (−2.3) | 18.8 (−7.3) | 12.6 (−10.8) | 27.7 (−2.4) |
| Mean minimum °F (°C) | −10.0 (−23.3) | −4.8 (−20.4) | 1.0 (−17.2) | 10.8 (−11.8) | 17.9 (−7.8) | 24.9 (−3.9) | 34.7 (1.5) | 36.4 (2.4) | 25.4 (−3.7) | 14.0 (−10.0) | 1.9 (−16.7) | −7.9 (−22.2) | −13.8 (−25.4) |
| Record low °F (°C) | −28 (−33) | −37 (−38) | −18 (−28) | −4 (−20) | 8 (−13) | 17 (−8) | 25 (−4) | 26 (−3) | 18 (−8) | −4 (−20) | −19 (−28) | −36 (−38) | −37 (−38) |
| Average precipitation inches (mm) | 2.07 (53) | 2.50 (64) | 2.28 (58) | 1.00 (25) | 0.82 (21) | 0.37 (9.4) | 2.72 (69) | 3.30 (84) | 1.95 (50) | 1.76 (45) | 1.48 (38) | 2.24 (57) | 22.49 (573.4) |
| Average snowfall inches (cm) | 16.70 (42.4) | 12.80 (32.5) | 13.60 (34.5) | 4.70 (11.9) | 0.50 (1.3) | 0.00 (0.00) | 0.00 (0.00) | 0.00 (0.00) | 0.00 (0.00) | 1.40 (3.6) | 5.80 (14.7) | 9.80 (24.9) | 65.3 (165.8) |
| Source 1: NOAA ||||||||||||||
| Source 2: XMACIS2 (records & monthly max/mins) ||||||||||||||