Climate averages 1991–2020
Decatur weather
in March.
A cool, moderately wet month: the 8th warmest and the 6th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
March is a cool month in Decatur: daytime highs average 10.7°C and nights cool to about 0.7°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 83 mm of rain on roughly 10 days, which makes March a moderately wet month (the 6th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 55 min on an average March day.
The nearest other city in this atlas is Springfield (Illinois), United States (59 km away). In March its highs average 10.9°C, about as warm as Decatur, with 80 mm of rain.
Among the 498 cities listed in the United States, Decatur ranks joint 340th of 498 for the warmest March highs and joint 288th of 498 for the driest March (rainfall, lowest first). The mean March high of those 498 cities is 14.9°C; Decatur is 4.2°C cooler than that mean.
From March to April, average highs rise by 6.4°C to 17.2°C, and monthly rainfall rises from 83 mm to 118 mm.
The annual picture
March in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Decatur climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.8°C-6.3°C | -6.3°C | 69 | 8.5 | 9.710 h |
| February | 4.6°C-4.7°C | -4.7°C | 59 | 7.6 | 10.711 h |
| March, selected | 10.7°C0.7°C | 0.7°C | 83 | 9.7 | 11.912 h |
| April | 17.2°C6.7°C | 6.7°C | 118 | 11.7 | 13.213 h |
| May | 22.5°C12.8°C | 12.8°C | 122 | 13.2 | 14.414 h |
| June | 27.1°C17.9°C | 17.9°C | 110 | 10.9 | 14.915 h |
| July | 28.8°C19.9°C | 19.9°C | 91 | 10.3 | 14.715 h |
| August | 28.3°C19.3°C | 19.3°C | 77 | 8.4 | 13.714 h |
| September | 25.0°C15.4°C | 15.4°C | 82 | 7.3 | 12.512 h |
| October | 18.2°C9.1°C | 9.1°C | 88 | 8.6 | 11.211 h |
| November | 10.5°C2.3°C | 2.3°C | 88 | 8.7 | 10.010 h |
| December | 4.3°C-3.1°C | -3.1°C | 63 | 8.7 | 9.49 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
March in nearby cities
- Springfield (Illinois), United States in MarchUnited States · 59 kmHigh 10.9°C · Low 0.8°C · 80 mm rain
- Champaign in MarchUnited States · 68 kmHigh 10.2°C · Low 0.0°C · 85 mm rain
- Bloomington (Illinois), United States in MarchUnited States · 72 kmHigh 9.8°C · Low -0.3°C · 78 mm rain
- Peoria (Illinois), United States in MarchUnited States · 109 kmHigh 9.9°C · Low 0.1°C · 75 mm rain
- St. Louis in MarchUnited States · 172 kmHigh 13.0°C · Low 2.6°C · 94 mm rain
- Lafayette (Indiana), United States in MarchUnited States · 188 kmHigh 9.7°C · Low -0.4°C · 84 mm rain
- O'Fallon in MarchUnited States · 189 kmHigh 12.6°C · Low 2.6°C · 92 mm rain
- Joliet in MarchUnited States · 201 kmHigh 8.7°C · Low -1.2°C · 72 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Decatur) is explained once on the Decatur year overview and on the Sources, method and limits page.