IL
Collinsville and O'Fallon have remarkably similar climates.
The year at a glance
Averages from 30 years of climate history, 1991-2020
| Collinsville | Metric | O'Fallon |
|---|---|---|
| 201 days | Sunny daysclear or partly cloudy skies | 203 days |
| 43 in | Precipitationper year | 43 in |
| 119 days | Wet daysrain or snow per year | 119 days |
| 12 in | Snowfallper year | 11 in |
| 46 days | Hot daysabove 90 °F | 50 days |
| 96 days | Freezing nightsat or below 32 °F | 94 days |
| 67% | Humidityaverage relative | 67% |
| 57 °F | Average temperatureyear round | 57 °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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Collinsville high | 41 | 47 | 57 | 68 | 77 | 86 | 89 | 88 | 81 | 70 | 56 | 45 |
| O'Fallon high | 42 | 48 | 58 | 70 | 78 | 87 | 90 | 89 | 82 | 72 | 57 | 46 |
| Collinsville low | 24 | 27 | 36 | 46 | 56 | 65 | 69 | 66 | 58 | 46 | 36 | 28 |
| O'Fallon low | 24 | 28 | 36 | 46 | 56 | 65 | 68 | 66 | 57 | 46 | 37 | 28 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Collinsville | 2.9 | 2.5 | 3.7 | 4.7 | 5.2 | 4.2 | 3.3 | 3.0 | 3.2 | 3.5 | 3.7 | 2.6 |
| O'Fallon | 2.9 | 2.6 | 3.8 | 4.8 | 5.1 | 4.1 | 3.4 | 2.9 | 3.2 | 3.5 | 3.7 | 2.8 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Collinsville | 14 | 12 | 15 | 15 | 16 | 17 | 21 | 22 | 21 | 20 | 16 | 14 |
| O'Fallon | 14 | 12 | 15 | 15 | 16 | 18 | 21 | 22 | 21 | 20 | 16 | 14 |
Keep comparing
Nearby cities and popular picks for each side of this matchup. Any two cities can be compared from the home page.
Collinsville vs another city
- Collinsville vs Maryville, IL
- Collinsville vs Pontoon Beach, IL
- Collinsville vs Fairview Heights, IL
- Collinsville vs Glen Carbon, IL
- Collinsville vs Troy, IL
- Collinsville vs New York, NY
- Collinsville vs Los Angeles, CA
- Collinsville vs Chicago, IL
- Collinsville vs Houston, TX
- Collinsville vs Phoenix, AZ
- Collinsville vs Philadelphia, PA
O'Fallon vs another city
- O'Fallon vs Shiloh, IL
- O'Fallon vs Fairview Heights, IL
- O'Fallon vs Swansea, IL
- O'Fallon vs Belleville, IL
- O'Fallon vs Mascoutah, IL
- 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
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).