Weather World
City of Decatur, Illinois
Decatur Monthly Climate Averages
January |
February |
March |
April |
May |
June |
July |
August |
September |
October |
November |
December |
| Hi 34°F Lo 21°F | Hi 39°F Lo 24°F | Hi 52°F Lo 36°F | Hi 62°F Lo 45°F | Hi 73°F Lo 56°F | Hi 81°F Lo 64°F | Hi 83°F Lo 67°F | Hi 82°F Lo 65°F | Hi 78°F Lo 59°F | Hi 65°F Lo 48°F | Hi 51°F Lo 36°F | Hi 40°F Lo 29°F |
| 11 mph | 11 mph | 11 mph | 11 mph | 9 mph | 8 mph | 7 mph | 7 mph | 8 mph | 10 mph | 10 mph | 10 mph |
| 2.5 in | 2.8 in | 4.3 in | 6.5 in | 5.6 in | 5.4 in | 5.2 in | 4 in | 4 in | 3.8 in | 3.5 in | 3 in |
| 78% | 78% | 74% | 74% | 76% | 78% | 83% | 80% | 72% | 68% | 71% | 77% |
| 56% | 54% | 49% | 47% | 43% | 33% | 34% | 32% | 30% | 36% | 40% | 54% |
| 30.1 in | 30.1 in | 30.0 in | 30.0 in | 30.0 in | 29.9 in | 30.0 in | 30.0 in | 30.0 in | 30.0 in | 30.1 in | 30.1 in |
| 20 | 19 | 22 | 22 | 21 | 21 | 23 | 23 | 25 | 24 | 24 | 22 |
| 7 | 6 | 8 | 7 | 10 | 9 | 8 | 8 | 5 | 7 | 5 | 7 |
| 4 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 |
| 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
| 2 | 2 | 3 | 4 | 5 | 5 | 5 | 5 | 5 | 3 | 2 | 1 |
| 132 | 131 | 156 | 159 | 176 | 220 | 219 | 232 | 236 | 207 | 191 | 145 |
January |
February |
March |
April |
May |
June |
July |
August |
September |
October |
November |
December |
| Hi 1°C Lo -6°C | Hi 4°C Lo -4°C | Hi 11°C Lo 2°C | Hi 17°C Lo 7°C | Hi 23°C Lo 13°C | Hi 27°C Lo 18°C | Hi 28°C Lo 19°C | Hi 28°C Lo 18°C | Hi 26°C Lo 15°C | Hi 19°C Lo 9°C | Hi 11°C Lo 3°C | Hi 5°C Lo -2°C |
| 17 km/h | 17 km/h | 17 km/h | 17 km/h | 14 km/h | 12 km/h | 10 km/h | 11 km/h | 12 km/h | 16 km/h | 16 km/h | 16 km/h |
| 63 mm | 70 mm | 108 mm | 164 mm | 143 mm | 138 mm | 131 mm | 101 mm | 103 mm | 95 mm | 89 mm | 75 mm |
| 78% | 78% | 74% | 74% | 76% | 78% | 83% | 80% | 72% | 68% | 71% | 77% |
| 56% | 54% | 49% | 47% | 43% | 33% | 34% | 32% | 30% | 36% | 40% | 54% |
| 1021 mb | 1020 mb | 1018 mb | 1014 mb | 1015 mb | 1013 mb | 1015 mb | 1015 mb | 1017 mb | 1017 mb | 1020 mb | 1020 mb |
| 20 | 19 | 22 | 22 | 21 | 21 | 23 | 23 | 25 | 24 | 24 | 22 |
| 7 | 6 | 8 | 7 | 10 | 9 | 8 | 8 | 5 | 7 | 5 | 7 |
| 4 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 |
| 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
| 2 | 2 | 3 | 4 | 5 | 5 | 5 | 5 | 5 | 3 | 2 | 1 |
| 132 | 131 | 156 | 159 | 176 | 220 | 219 | 232 | 236 | 207 | 191 | 145 |
| Month |
| Avg. Temperatures |
| Avg. Wind Speed |
| Avg. Precipitation |
| Average Humidity |
| Avg. Cloud Cover |
| Pressure Average |
| Average Dry Days |
| Avg. Precip. Days |
| Avg. Snow Days |
| Average Fog Days |
| Average UV Index |
| Avg. Hours of Sun |
Averages are based on historical weather data from the past 10 years.