Hot-summer humid continental climate
Climate Ottawa - Illinois
Annual high60ºF
Annual low41ºF
Precipitation32.61 inch
| Month | HighºF | LowºF | Precipinch | Snowinch |
|---|---|---|---|---|
| Jan | 31 | 15 | 1.48 | 8 |
| Feb | 36 | 19 | 1.43 | 5 |
| Mar | 49 | 29 | 2.46 | 3 |
| Apr | 62 | 40 | 3.22 | 1 |
| May | 72 | 51 | 4.11 | 0 |
| Jun | 81 | 60 | 3.98 | 0 |
| Jul | 84 | 64 | 3.85 | 0 |
| Aug | 83 | 62 | 3.89 | 0 |
| Sep | 77 | 54 | 3.26 | 0 |
| Oct | 65 | 42 | 2.80 | 0 |
| Nov | 49 | 30 | 0.00 | 0 |
| Dec | 36 | 20 | 2.13 | 5 |
- JanHigh 31ºFLow 15ºFPrecip 1.48 inch
- FebHigh 36ºFLow 19ºFPrecip 1.43 inch
- MarHigh 49ºFLow 29ºFPrecip 2.46 inch
- AprHigh 62ºFLow 40ºFPrecip 3.22 inch
- MayHigh 72ºFLow 51ºFPrecip 4.11 inch
- JunHigh 81ºFLow 60ºFPrecip 3.98 inch
- JulHigh 84ºFLow 64ºFPrecip 3.85 inch
- AugHigh 83ºFLow 62ºFPrecip 3.89 inch
- SepHigh 77ºFLow 54ºFPrecip 3.26 inch
- OctHigh 65ºFLow 42ºFPrecip 2.80 inch
- NovHigh 49ºFLow 30ºFPrecip 0.00 inch
- DecHigh 36ºFLow 20ºFPrecip 2.13 inch
Climate summary
What is the average weather in Ottawa, Illinois?
Ottawa experiences a humid continental climate, marked by very strong seasonal temperature contrasts. Summers are warm, while winters are cold and bring regular snowfall. The area is fairly wet, with precipitation spread relatively evenly throughout the year, though summers tend to be wetter and winters drier.
Ottawa weather averages
Annual high60ºF
Annual low41ºF
Precipitation32.61 inch
Snowfall22 inch
Daily normals Ottawa - Illinois - January
| Day | HighºF | LowºF | Prec/ | Prec/ | Snow/ | Snow/ |
|---|---|---|---|---|---|---|
| Jan 1 | 31.9 | 17.1 | 0.06 | 0.06 | 0.30 | 0.30 |
| Jan 2 | 31.7 | 16.9 | 0.13 | 0.13 | 0.50 | 0.50 |
| Jan 3 | 31.5 | 16.7 | 0.19 | 0.19 | 0.80 | 0.80 |
| Jan 4 | 31.4 | 16.5 | 0.26 | 0.26 | 1.10 | 1.10 |
| Jan 5 | 31.2 | 16.3 | 0.32 | 0.32 | 1.40 | 1.40 |
| Jan 6 | 31.1 | 16.1 | 0.38 | 0.38 | 1.70 | 1.70 |
| Jan 7 | 31.0 | 15.9 | 0.45 | 0.45 | 2.00 | 2.00 |
| Jan 8 | 30.9 | 15.8 | 0.51 | 0.51 | 2.30 | 2.30 |
| Jan 9 | 30.8 | 15.6 | 0.58 | 0.58 | 2.70 | 2.70 |
| Jan 10 | 30.7 | 15.5 | 0.65 | 0.65 | 3.00 | 3.00 |
| Jan 11 | 30.6 | 15.3 | 0.72 | 0.72 | 3.30 | 3.30 |
| Jan 12 | 30.5 | 15.2 | 0.78 | 0.78 | 3.60 | 3.60 |
| Jan 13 | 30.4 | 15.0 | 0.85 | 0.85 | 3.90 | 3.90 |
| Jan 14 | 30.4 | 14.9 | 0.91 | 0.91 | 4.30 | 4.30 |
| Jan 15 | 30.3 | 14.8 | 0.97 | 0.97 | 4.60 | 4.60 |
| Jan 16 | 30.3 | 14.7 | 1.03 | 1.03 | 4.90 | 4.90 |
| Jan 17 | 30.2 | 14.6 | 1.09 | 1.09 | 5.30 | 5.30 |
| Jan 18 | 30.2 | 14.6 | 1.15 | 1.15 | 5.60 | 5.60 |
| Jan 19 | 30.2 | 14.5 | 1.21 | 1.21 | 5.90 | 5.90 |
| Jan 20 | 30.2 | 14.5 | 1.26 | 1.26 | 6.20 | 6.20 |
| Jan 21 | 30.2 | 14.4 | 1.31 | 1.31 | 6.50 | 6.50 |
| Jan 22 | 30.3 | 14.4 | 1.37 | 1.37 | 6.80 | 6.80 |
| Jan 23 | 30.3 | 14.4 | 1.42 | 1.42 | 7.10 | 7.10 |
| Jan 24 | 30.4 | 14.4 | 1.47 | 1.47 | 7.40 | 7.40 |
| Jan 25 | 30.4 | 14.5 | 1.52 | 1.52 | 7.70 | 7.70 |
| Jan 26 | 30.5 | 14.5 | 1.57 | 1.57 | 7.90 | 7.90 |
| Jan 27 | 30.6 | 14.6 | 1.61 | 1.61 | 8.20 | 8.20 |
| Jan 28 | 30.7 | 14.7 | 1.66 | 1.66 | 8.50 | 8.50 |
| Jan 29 | 30.8 | 14.8 | 1.70 | 1.70 | 8.70 | 8.70 |
| Jan 30 | 31.0 | 14.9 | 1.74 | 1.74 | 9.00 | 9.00 |
| Jan 31 | 31.1 | 15.0 | 1.78 | 1.78 | 9.20 | 9.20 |
Precipitation and snow add up through the month (/mo) and the year (/yr)
Weather history Ottawa - October 2026
| Day | HighºF | LowºF | Precip.inch |
|---|---|---|---|
| Oct 1 | 64.0 | 59.0 | 0.81 |
| Oct 2 | 69.1 | 48.9 | 1.32 |
| Oct 3 | 66.9 | 43.0 | 0.00 |
| Oct 4 | – | – | – |
| Oct 5 | – | – | – |
| Oct 6 | – | – | – |
| Oct 7 | – | – | – |
| Oct 8 | 80.1 | 51.1 | 0.00 |
| Oct 9 | 75.9 | 50.0 | 0.00 |
| Oct 10 | 64.9 | 51.1 | 0.06 |
| Oct 11 | 82.0 | 48.9 | 0.00 |
| Oct 12 | 80.1 | 50.0 | 0.00 |
| Oct 13 | 86.0 | 62.1 | 0.00 |
| Oct 14 | 78.1 | 62.1 | 0.05 |
| Oct 15 | – | – | – |
| Oct 16 | 64.9 | 45.0 | 0.80 |
| Oct 17 | – | – | – |
| Oct 18 | – | – | – |
| Oct 19 | 63.0 | 37.0 | 0.00 |
| Oct 20 | – | – | – |
| Oct 21 | – | – | – |
| Oct 22 | 72.0 | 41.0 | 0.00 |
| Oct 23 | 73.9 | 45.0 | 0.00 |
| Oct 24 | 73.9 | 46.0 | 0.00 |
| Oct 25 | 73.0 | 46.0 | 0.00 |
| Oct 26 | 75.0 | 46.9 | 0.00 |
| Oct 27 | 71.1 | 46.0 | 0.00 |
| Oct 28 | 71.1 | 46.9 | 0.00 |
| Oct 29 | 75.9 | 51.1 | 0.01 |
| Oct 30 | 68.0 | 42.1 | 0.05 |
| Oct 31 | 55.0 | 42.1 | 0.07 |
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
- Highest max temperature86.0ºF · Oct 13
- Lowest max temperature55.0ºF · Oct 31
- Highest min temperature62.1ºF · Oct 13
- Lowest min temperature37.0ºF · Oct 19
Geo Ottawa - Illinois
Location
- Country
- United States
- State
- Illinois
- County
- LaSalle
- City
- Ottawa
- Zip Code
- 61350
- Elevation
- 617 ft
- Longitude
- -88.79
- Latitude
- 41.40
- ICAO
- –
- IATA
- –