O'Fallon and St. Peters have remarkably similar climates.
The year at a glance
Averages from 30 years of climate history, 1991-2020
| O'Fallon | Metric | St. Peters |
|---|---|---|
| 203 days | Sunny daysclear or partly cloudy skies | 202 days |
| 41 in | Precipitationper year | 41 in |
| 117 days | Wet daysrain or snow per year | 118 days |
| 13 in | Snowfallper year | 14 in |
| 38 days | Hot daysabove 90 °F | 39 days |
| 104 days | Freezing nightsat or below 32 °F | 104 days |
| 69% | Humidityaverage relative | 69% |
| 55 °F | Average temperatureyear round | 55 °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 |
| St. Peters high | 39 | 45 | 55 | 67 | 76 | 84 | 88 | 87 | 81 | 69 | 55 | 44 |
| O'Fallon low | 21 | 25 | 33 | 44 | 54 | 64 | 67 | 65 | 57 | 45 | 35 | 26 |
| St. Peters low | 21 | 25 | 33 | 43 | 54 | 63 | 67 | 65 | 57 | 45 | 35 | 26 |
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 |
| St. Peters | 2.6 | 2.4 | 3.7 | 4.5 | 4.9 | 4.0 | 3.3 | 2.9 | 3.2 | 3.3 | 3.6 | 2.5 |
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 |
| St. Peters | 14 | 13 | 15 | 15 | 16 | 17 | 21 | 22 | 21 | 19 | 17 | 14 |
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 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 Phoenix, AZ
- O'Fallon vs Philadelphia, PA
St. Peters vs another city
- St. Peters vs Cottleville, MO
- St. Peters vs St. Charles, MO
- St. Peters vs Weldon Spring, MO
- St. Peters vs Dardenne Prairie, MO
- St. Peters vs Maryland Heights, MO
- St. Peters vs New York, NY
- St. Peters vs Los Angeles, CA
- St. Peters vs Chicago, IL
- St. Peters vs Houston, TX
- St. Peters vs Phoenix, AZ
- St. Peters vs Philadelphia, PA
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).