Hot-summer humid continental climate
Climate Sullivan - Illinois
Annual high62ºF
Annual low42ºF
Precipitation39.77 inch
| Month | HighºF | LowºF | Precipinch | Snowinch |
|---|---|---|---|---|
| Jan | 35 | 18 | 2.38 | 6 |
| Feb | 39 | 21 | 2.18 | 3 |
| Mar | 50 | 31 | 2.59 | 1 |
| Apr | 63 | 40 | 3.67 | 0 |
| May | 73 | 51 | 4.50 | 0 |
| Jun | 83 | 61 | 4.44 | 0 |
| Jul | 85 | 65 | 4.34 | 0 |
| Aug | 85 | 61 | 3.06 | 0 |
| Sep | 77 | 53 | 2.61 | 0 |
| Oct | 66 | 42 | 3.25 | 0 |
| Nov | 51 | 32 | 3.60 | 0 |
| Dec | 38 | 22 | 3.15 | 3 |
- JanHigh 35ºFLow 18ºFPrecip 2.38 inch
- FebHigh 39ºFLow 21ºFPrecip 2.18 inch
- MarHigh 50ºFLow 31ºFPrecip 2.59 inch
- AprHigh 63ºFLow 40ºFPrecip 3.67 inch
- MayHigh 73ºFLow 51ºFPrecip 4.50 inch
- JunHigh 83ºFLow 61ºFPrecip 4.44 inch
- JulHigh 85ºFLow 65ºFPrecip 4.34 inch
- AugHigh 85ºFLow 61ºFPrecip 3.06 inch
- SepHigh 77ºFLow 53ºFPrecip 2.61 inch
- OctHigh 66ºFLow 42ºFPrecip 3.25 inch
- NovHigh 51ºFLow 32ºFPrecip 3.60 inch
- DecHigh 38ºFLow 22ºFPrecip 3.15 inch
Climate summary
What is the average weather in Sullivan, Illinois?
Sullivan experiences a humid continental climate, marked by a very large seasonal temperature contrast. Summers are warm and fairly wet, with precipitation spread relatively evenly throughout the year. Winters are cold and bring regular snowfall, with winter being the driest season overall.
Sullivan weather averages
Annual high62ºF
Annual low42ºF
Precipitation39.77 inch
Snowfall13 inch
Daily normals Sullivan - Illinois - January
| Day | HighºF | LowºF | Prec/ | Prec/ | Snow/ | Snow/ |
|---|---|---|---|---|---|---|
| Jan 1 | 36.0 | 20.6 | 0.09 | 0.09 | 0.10 | 0.10 |
| Jan 2 | 35.8 | 20.4 | 0.19 | 0.19 | 0.30 | 0.30 |
| Jan 3 | 35.7 | 20.2 | 0.28 | 0.28 | 0.40 | 0.40 |
| Jan 4 | 35.5 | 19.9 | 0.38 | 0.38 | 0.60 | 0.60 |
| Jan 5 | 35.4 | 19.7 | 0.47 | 0.47 | 0.70 | 0.70 |
| Jan 6 | 35.3 | 19.5 | 0.56 | 0.56 | 0.90 | 0.90 |
| Jan 7 | 35.2 | 19.3 | 0.65 | 0.65 | 1.10 | 1.10 |
| Jan 8 | 35.1 | 19.1 | 0.74 | 0.74 | 1.30 | 1.30 |
| Jan 9 | 35.0 | 18.9 | 0.82 | 0.82 | 1.50 | 1.50 |
| Jan 10 | 34.9 | 18.8 | 0.90 | 0.90 | 1.60 | 1.60 |
| Jan 11 | 34.9 | 18.6 | 0.98 | 0.98 | 1.80 | 1.80 |
| Jan 12 | 34.8 | 18.5 | 1.06 | 1.06 | 2.00 | 2.00 |
| Jan 13 | 34.8 | 18.3 | 1.14 | 1.14 | 2.20 | 2.20 |
| Jan 14 | 34.8 | 18.2 | 1.22 | 1.22 | 2.40 | 2.40 |
| Jan 15 | 34.8 | 18.1 | 1.29 | 1.29 | 2.60 | 2.60 |
| Jan 16 | 34.8 | 18.0 | 1.38 | 1.38 | 2.80 | 2.80 |
| Jan 17 | 34.8 | 17.9 | 1.45 | 1.45 | 2.90 | 2.90 |
| Jan 18 | 34.8 | 17.8 | 1.53 | 1.53 | 3.10 | 3.10 |
| Jan 19 | 34.9 | 17.7 | 1.60 | 1.60 | 3.30 | 3.30 |
| Jan 20 | 35.0 | 17.7 | 1.67 | 1.67 | 3.50 | 3.50 |
| Jan 21 | 35.0 | 17.7 | 1.74 | 1.74 | 3.60 | 3.60 |
| Jan 22 | 35.1 | 17.6 | 1.81 | 1.81 | 3.80 | 3.80 |
| Jan 23 | 35.2 | 17.7 | 1.87 | 1.87 | 4.00 | 4.00 |
| Jan 24 | 35.3 | 17.7 | 1.94 | 1.94 | 4.20 | 4.20 |
| Jan 25 | 35.5 | 17.7 | 2.01 | 2.01 | 4.30 | 4.30 |
| Jan 26 | 35.6 | 17.8 | 2.08 | 2.08 | 4.50 | 4.50 |
| Jan 27 | 35.7 | 17.8 | 2.15 | 2.15 | 4.70 | 4.70 |
| Jan 28 | 35.9 | 17.9 | 2.22 | 2.22 | 4.80 | 4.80 |
| Jan 29 | 36.1 | 18.0 | 2.28 | 2.28 | 4.90 | 4.90 |
| Jan 30 | 36.2 | 18.1 | 2.35 | 2.35 | 5.10 | 5.10 |
| Jan 31 | 36.4 | 18.3 | 2.41 | 2.41 | 5.20 | 5.20 |
Precipitation and snow add up through the month (/mo) and the year (/yr)
Weather history Sullivan - January 2026
| Day | HighºF | LowºF | Precip.inch | Snowinch | Snow depthinch |
|---|---|---|---|---|---|
| Jan 1 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 2 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 3 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 4 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 5 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 6 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 7 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 8 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 9 | – | – | 0.92 | 0.00 | 0.0 |
| Jan 10 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 11 | – | – | T | T | T |
| Jan 12 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 13 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 14 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 15 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 16 | – | – | – | – | – |
| Jan 17 | – | – | – | – | – |
| Jan 18 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 19 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 20 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 21 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 22 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 23 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 24 | – | – | 0.00 | 0.00 | 0.0 |
| Jan 25 | – | – | – | – | – |
| Jan 26 | – | – | – | – | – |
| Jan 27 | – | – | 0.00 | 0.00 | – |
| Jan 28 | – | – | 0.00 | 0.00 | – |
| Jan 29 | – | – | 0.00 | 0.00 | – |
| Jan 30 | – | – | 0.00 | 0.00 | – |
| Jan 31 | – | – | 0.00 | 0.00 | – |
The data for January 2026 is incomplete: some days or values are missing.
- –No data
- –Not yet observed or received
- TTrace, too small to measure
Observed extremes
Geo Sullivan - Illinois
Location
- Country
- United States
- State
- Illinois
- County
- –
- City
- Sullivan
- Zip Code
- 61951
- Elevation
- 673 ft
- Longitude
- -88.61
- Latitude
- 39.60
- ICAO
- –
- IATA
- –