Harrisburg, IL
Climate overview — based on NOAA 1991-2020 normals from HARRISBURG, IL US.
Year-round temperatures (°F)
Climate summary
Harrisburg has an annual average temperature of 57.3°F with about 47.6 inches of precipitation per year. The warmest month is July (average high 89.1°F), and the coldest is January (average low 24.0°F). April is typically the wettest month (5.26 in) and September the driest (3.10 in).
Best time to visit Harrisburg
Full guide →Climate change signal
All-time records →10 of 366 (2.7%) of Harrisburg's all-time daily heat records have been set since 2015. If records were spread evenly across the station's history, only about 5% would fall in any given decade.
| 1890s | 1 | |
| 1900s | 28 | |
| 1910s | 67 | |
| 1920s | 54 | |
| 1930s | 79 | |
| 1940s | 20 | |
| 1950s | 33 | |
| 1960s | 26 | |
| 1970s | 8 | |
| 1980s | 12 | |
| 1990s | 3 | |
| 2000s | 15 | |
| 2010s | 10 | |
| 2020s | 10 |
Bars: number of all-time daily heat records still standing that were set in each decade.
Monthly averages
| Month | Avg High | Avg Low | Avg Temp | Precipitation | Snow | Rainy days |
|---|---|---|---|---|---|---|
| January | 42.9°F | 24.0°F | 33.4°F | 3.79 in | — | 8 |
| February | 47.7°F | 28.3°F | 38.0°F | 3.13 in | — | 6 |
| March | 58.1°F | 36.1°F | 47.1°F | 4.90 in | — | 9 |
| April | 69.4°F | 45.7°F | 57.6°F | 5.26 in | — | 11 |
| May | 78.2°F | 56.5°F | 67.3°F | 4.31 in | — | 9 |
| June | 86.0°F | 65.1°F | 75.5°F | 4.92 in | — | 8 |
| July | 89.1°F | 68.4°F | 78.7°F | 3.49 in | — | 7 |
| August | 88.2°F | 65.6°F | 76.9°F | 3.58 in | — | 6 |
| September | 82.4°F | 57.3°F | 69.8°F | 3.10 in | — | 6 |
| October | 71.2°F | 45.4°F | 58.3°F | 3.76 in | — | 6 |
| November | 57.4°F | 36.3°F | 46.8°F | 3.97 in | — | 8 |
| December | 46.8°F | 28.9°F | 37.8°F | 3.38 in | — | 8 |
Climate twins of Harrisburg
Why these? →The most climatically similar US cities at least 140 miles away (by monthly temperature + precipitation pattern).