Hot-summer humid continental climate
Climate Decatur - Illinois
Annual high64ºF
Annual low43ºF
Precipitation40.32 inch
| Month | HighºF | LowºF | Precipinch | Snowinch |
|---|---|---|---|---|
| Jan | 36 | 19 | 2.14 | 5 |
| Feb | 41 | 23 | 2.00 | 4 |
| Mar | 53 | 32 | 2.59 | 2 |
| Apr | 66 | 43 | 3.67 | 0 |
| May | 76 | 53 | 4.79 | 0 |
| Jun | 85 | 62 | 4.50 | 0 |
| Jul | 87 | 66 | 3.98 | 0 |
| Aug | 86 | 64 | 3.77 | 0 |
| Sep | 80 | 56 | 3.14 | 0 |
| Oct | 68 | 45 | 3.25 | 0 |
| Nov | 53 | 34 | 3.71 | 0 |
| Dec | 39 | 23 | 2.78 | 5 |
- JanHigh 36ºFLow 19ºFPrecip 2.14 inch
- FebHigh 41ºFLow 23ºFPrecip 2.00 inch
- MarHigh 53ºFLow 32ºFPrecip 2.59 inch
- AprHigh 66ºFLow 43ºFPrecip 3.67 inch
- MayHigh 76ºFLow 53ºFPrecip 4.79 inch
- JunHigh 85ºFLow 62ºFPrecip 4.50 inch
- JulHigh 87ºFLow 66ºFPrecip 3.98 inch
- AugHigh 86ºFLow 64ºFPrecip 3.77 inch
- SepHigh 80ºFLow 56ºFPrecip 3.14 inch
- OctHigh 68ºFLow 45ºFPrecip 3.25 inch
- NovHigh 53ºFLow 34ºFPrecip 3.71 inch
- DecHigh 39ºFLow 23ºFPrecip 2.78 inch
Climate summary
What is the average weather in Decatur, Illinois?
Decatur experiences a humid continental climate, marked by very strong seasonal temperature contrasts. Summers are hot, while winters are cold and bring regular snowfall. The area is fairly wet overall, with precipitation spread relatively evenly throughout the year, though summer tends to be wetter.
Decatur weather averages
Annual high64ºF
Annual low43ºF
Precipitation40.32 inch
Snowfall16 inch
Daily normals Decatur - Illinois - January
| Day | HighºF | LowºF | Prec/ | Prec/ | Snow/ | Snow/ |
|---|---|---|---|---|---|---|
| Jan 1 | 34.7 | 21.4 | 0.10 | 0.10 | 0.20 | 0.20 |
| Jan 2 | 34.6 | 21.2 | 0.19 | 0.19 | 0.40 | 0.40 |
| Jan 3 | 34.4 | 21.0 | 0.28 | 0.28 | 0.60 | 0.60 |
| Jan 4 | 34.3 | 20.8 | 0.38 | 0.38 | 0.80 | 0.80 |
| Jan 5 | 34.2 | 20.6 | 0.47 | 0.47 | 1.00 | 1.00 |
| Jan 6 | 34.0 | 20.4 | 0.56 | 0.56 | 1.20 | 1.20 |
| Jan 7 | 33.9 | 20.3 | 0.65 | 0.65 | 1.40 | 1.40 |
| Jan 8 | 33.9 | 20.1 | 0.74 | 0.74 | 1.60 | 1.60 |
| Jan 9 | 33.8 | 20.0 | 0.82 | 0.82 | 1.80 | 1.80 |
| Jan 10 | 33.7 | 19.8 | 0.91 | 0.91 | 2.00 | 2.00 |
| Jan 11 | 33.6 | 19.7 | 0.99 | 0.99 | 2.20 | 2.20 |
| Jan 12 | 33.6 | 19.6 | 1.06 | 1.06 | 2.40 | 2.40 |
| Jan 13 | 33.6 | 19.5 | 1.14 | 1.14 | 2.60 | 2.60 |
| Jan 14 | 33.5 | 19.4 | 1.21 | 1.21 | 2.80 | 2.80 |
| Jan 15 | 33.5 | 19.3 | 1.29 | 1.29 | 3.10 | 3.10 |
| Jan 16 | 33.5 | 19.2 | 1.37 | 1.37 | 3.30 | 3.30 |
| Jan 17 | 33.5 | 19.1 | 1.45 | 1.45 | 3.50 | 3.50 |
| Jan 18 | 33.6 | 19.1 | 1.53 | 1.53 | 3.70 | 3.70 |
| Jan 19 | 33.6 | 19.1 | 1.60 | 1.60 | 3.90 | 3.90 |
| Jan 20 | 33.6 | 19.0 | 1.67 | 1.67 | 4.10 | 4.10 |
| Jan 21 | 33.7 | 19.0 | 1.74 | 1.74 | 4.20 | 4.20 |
| Jan 22 | 33.8 | 19.0 | 1.82 | 1.82 | 4.40 | 4.40 |
| Jan 23 | 33.9 | 19.1 | 1.89 | 1.89 | 4.60 | 4.60 |
| Jan 24 | 34.0 | 19.1 | 1.96 | 1.96 | 4.80 | 4.80 |
| Jan 25 | 34.1 | 19.2 | 2.03 | 2.03 | 5.00 | 5.00 |
| Jan 26 | 34.2 | 19.2 | 2.09 | 2.09 | 5.20 | 5.20 |
| Jan 27 | 34.3 | 19.3 | 2.16 | 2.16 | 5.30 | 5.30 |
| Jan 28 | 34.5 | 19.4 | 2.22 | 2.22 | 5.50 | 5.50 |
| Jan 29 | 34.6 | 19.5 | 2.28 | 2.28 | 5.60 | 5.60 |
| Jan 30 | 34.8 | 19.7 | 2.34 | 2.34 | 5.80 | 5.80 |
| Jan 31 | 35.0 | 19.8 | 2.40 | 2.40 | 5.90 | 5.90 |
Precipitation and snow add up through the month (/mo) and the year (/yr)
Weather history Decatur - October 2026
| Day | HighºF | LowºF | Precip.inch |
|---|---|---|---|
| Oct 1 | – | – | 0.71 |
| Oct 2 | – | – | T |
| Oct 3 | – | – | 0.00 |
| Oct 4 | – | – | – |
| Oct 5 | – | – | – |
| Oct 6 | – | – | – |
| Oct 7 | – | – | 0.00 |
| Oct 8 | – | – | 0.00 |
| Oct 9 | – | – | 0.00 |
| Oct 10 | – | – | 0.00 |
| Oct 11 | – | – | 0.00 |
| Oct 12 | – | – | 0.00 |
| Oct 13 | – | – | 0.00 |
| Oct 14 | – | – | 0.00 |
| Oct 15 | – | – | 0.61 |
| Oct 16 | – | – | – |
| Oct 17 | – | – | – |
| Oct 18 | – | – | 0.00 |
| Oct 19 | – | – | – |
| Oct 20 | – | – | – |
| Oct 21 | – | – | – |
| Oct 22 | – | – | 0.00 |
| Oct 23 | – | – | 0.00 |
| Oct 24 | – | – | 0.00 |
| Oct 25 | – | – | 0.00 |
| Oct 26 | – | – | 0.00 |
| Oct 27 | – | – | 0.00 |
| Oct 28 | – | – | 0.00 |
| Oct 29 | – | – | – |
| Oct 30 | – | – | – |
| Oct 31 | – | – | – |
The data for October 2026 is incomplete: some days or values are missing.
- –No data
- –Not yet observed or received
- TTrace, too small to measure
Observed extremes
Geo Decatur - Illinois
Location
- Country
- United States
- State
- Illinois
- County
- –
- City
- Decatur
- Zip Code
- 62521
- Elevation
- 676 ft
- Longitude
- -88.95
- Latitude
- 39.84
- ICAO
- –
- IATA
- –