Crystal Lake, IL
Climate overview — based on NOAA 1991-2020 normals from CRYSTAL LAKE 4NW, IL US.
Year-round temperatures (°F)
Climate summary
Crystal Lake has an annual average temperature of 49.2°F with about 39.3 inches of precipitation per year and 35.1 inches of snow. The warmest month is July (average high 84.0°F), and the coldest is January (average low 14.2°F). June is typically the wettest month (5.26 in) and February the driest (1.84 in). Snow typically falls from October through April.
Best time to visit Crystal Lake
Full guide →Climate change signal
All-time records →254 of 366 (69.4%) of Crystal Lake'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.
| 1990s | 0 | |
| 2000s | 0 | |
| 2010s | 215 | |
| 2020s | 151 |
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 | 31.5°F | 14.2°F | 22.9°F | 1.97 in | 10.0 in | 9 |
| February | 35.2°F | 16.3°F | 25.8°F | 1.84 in | 9.0 in | 8 |
| March | 46.8°F | 26.4°F | 36.6°F | 2.51 in | 4.4 in | 8 |
| April | 59.2°F | 36.7°F | 48.0°F | 3.76 in | 1.2 in | 11 |
| May | 71.3°F | 47.9°F | 59.6°F | 4.98 in | — | 12 |
| June | 80.3°F | 58.4°F | 69.4°F | 5.26 in | — | 10 |
| July | 84.0°F | 62.5°F | 73.3°F | 3.90 in | — | 9 |
| August | 82.0°F | 61.2°F | 71.6°F | 3.81 in | — | 9 |
| September | 74.4°F | 52.4°F | 63.4°F | 3.54 in | — | 8 |
| October | 61.9°F | 42.4°F | 52.2°F | 3.20 in | 0.2 in | 9 |
| November | 47.5°F | 30.5°F | 39.0°F | 2.48 in | 1.6 in | 9 |
| December | 35.5°F | 20.4°F | 28.0°F | 2.10 in | 8.7 in | 9 |
Climate twins of Crystal Lake
Why these? →The most climatically similar US cities at least 140 miles away (by monthly temperature + precipitation pattern).