St. Helena, CA vs Phoenix, AZ
Side-by-side comparison of monthly climate normals (NOAA 1991-2020).
St. Helena is cooler than Phoenix (61°F vs 72.5°F annual avg) and wetter than it (34 in vs 8.9 in per year). St. Helena has a Hot-summer Mediterranean climate; Phoenix a Desert (hot) climate.
St. Helena, CA
Annual avg
61°F
Annual precip
34 in
Warmest month
August (88.8°F)
Coldest month
December (39.6°F)
Annual swing
23.5°F
Pleasant months
1 / 12
Hot-summer Mediterranean Csa
USDA Zone 9a
Phoenix, AZ
Annual avg
72.5°F
Annual precip
8.9 in
Warmest month
July (104.0°F)
Coldest month
December (42.7°F)
Annual swing
39.1°F
Pleasant months
2 / 12
Desert (hot) BWh
USDA Zone 9b
Best months to visit each city
St. Helena
J
F
M
A
M
J
J
A
S
O
N
D
Phoenix
J
F
M
A
M
J
J
A
S
O
N
D
Month-by-month comparison
| Month | St. Helena | Phoenix | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 58.8°F | 40.2°F | 6.47 in | 65.4°F | 44.1°F | 1.17 in |
| February | 62.5°F | 41.9°F | 6.71 in | 68.1°F | 46.1°F | 1.21 in |
| March | 66.8°F | 43.9°F | 4.98 in | 75.0°F | 50.9°F | 1.09 in |
| April | 71.8°F | 46.3°F | 1.97 in | 82.5°F | 56.6°F | 0.35 in |
| May | 78.1°F | 50.5°F | 1.31 in | 91.5°F | 64.7°F | 0.19 in |
| June | 85.4°F | 54.2°F | 0.35 in | 101.5°F | 72.7°F | 0.03 in |
| July | 88.7°F | 56.0°F | 0.01 in | 104.0°F | 80.8°F | 0.81 in |
| August | 88.8°F | 55.7°F | 0.04 in | 102.5°F | 80.5°F | 0.96 in |
| September | 86.6°F | 53.8°F | 0.06 in | 97.5°F | 74.7°F | 0.71 in |
| October | 78.1°F | 49.4°F | 1.65 in | 86.3°F | 62.7°F | 0.67 in |
| November | 65.8°F | 43.7°F | 3.24 in | 74.0°F | 50.8°F | 0.90 in |
| December | 58.3°F | 39.6°F | 7.18 in | 63.9°F | 42.7°F | 0.81 in |
Full climate profile
Phoenix overviewFull climate profile