The year at a glance
Averages from 30 years of climate history, 1991-2020
| O'Fallon | Metric | Phoenix |
|---|---|---|
| 203 days | Sunny daysclear or partly cloudy skies | 307 days |
| 41 in | Precipitationper year | 7 in |
| 117 days | Wet daysrain or snow per year | 33 days |
| 13 in | Snowfallper year | 0 in |
| 38 days | Hot daysabove 90 °F | 163 days |
| 104 days | Freezing nightsat or below 32 °F | 2 days |
| 69% | Humidityaverage relative | 35% |
| 55 °F | Average temperatureyear round | 74 °F |
Monthly temperatures
Average daily high and low for each month, in °F. The gap between the two lines is what an ordinary day feels like across the year.
Daily highs
Daily lows
View monthly temperatures as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| O'Fallon high | 40 | 45 | 56 | 67 | 76 | 84 | 88 | 87 | 80 | 69 | 55 | 44 |
| Phoenix high | 66 | 69 | 76 | 83 | 92 | 102 | 105 | 103 | 98 | 87 | 75 | 65 |
| O'Fallon low | 21 | 25 | 33 | 44 | 54 | 64 | 67 | 65 | 57 | 45 | 35 | 26 |
| Phoenix low | 44 | 47 | 52 | 58 | 67 | 75 | 82 | 82 | 76 | 64 | 51 | 43 |
Monthly precipitation
Total rain plus melted snow for each month, in inches. Taller bars mean wetter months.
View monthly precipitation as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| O'Fallon | 2.5 | 2.4 | 3.6 | 4.5 | 4.9 | 4.0 | 3.2 | 3.0 | 3.2 | 3.3 | 3.5 | 2.4 |
| Phoenix | 0.9 | 1.1 | 0.8 | 0.2 | 0.1 | 0.1 | 0.6 | 0.9 | 0.7 | 0.6 | 0.5 | 0.8 |
Monthly sunny days
Days each month with clear or partly cloudy skies, so compare the same month between cities.
View monthly sunny days as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| O'Fallon | 15 | 13 | 15 | 15 | 16 | 17 | 21 | 22 | 21 | 19 | 17 | 14 |
| Phoenix | 23 | 21 | 25 | 27 | 29 | 29 | 24 | 26 | 28 | 28 | 25 | 24 |
Keep comparing
Nearby cities and popular picks for each side of this matchup. Any two cities can be compared from the home page.
O'Fallon vs another city
- O'Fallon vs Dardenne Prairie, MO
- O'Fallon vs Lake St. Louis, MO
- O'Fallon vs Cottleville, MO
- O'Fallon vs St. Peters, MO
- O'Fallon vs Weldon Spring, MO
- O'Fallon vs Wentzville, MO
- O'Fallon vs New York, NY
- O'Fallon vs Los Angeles, CA
- O'Fallon vs Chicago, IL
- O'Fallon vs Houston, TX
- O'Fallon vs Philadelphia, PA
Phoenix vs another city
- Phoenix vs Glendale, AZ
- Phoenix vs Paradise Valley, AZ
- Phoenix vs Sun City, AZ
- Phoenix vs Youngtown, AZ
- Phoenix vs Tolleson, AZ
- Phoenix vs El Mirage, AZ
- Phoenix vs New York, NY
- Phoenix vs Los Angeles, CA
- Phoenix vs Chicago, IL
- Phoenix vs Houston, TX
- Phoenix vs Philadelphia, PA
- Phoenix vs San Antonio, TX
About this data
Every figure on this page is a 30 year average computed from daily climate history for 1991-2020, using each city's own coordinates. Wet days count days with measurable precipitation, calibrated against the wet day counts in NOAA's published climate normals. Sunny days count clear plus partly cloudy days, defined as average cloud cover of 63 percent or less and calibrated against NOAA's published sky cover tables. Snowfall figures are model estimates anchored to NOAA station measurements near each city.
Weather data by Open-Meteo.com (CC BY 4.0). Contains modified Copernicus Climate Change Service information (ERA5, ERA5-Land).