Crystal Lake, IL Weather & Climate Normals
What a normal year in Crystal Lake actually looks like
On the 30-year record NOAA keeps for Crystal Lake, IL, the comfort score comes out to 44/100, strongly seasonal: Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. Only 5 months a year land in the 55–75°F range this site treats as mild.
How much Crystal Lake's weather actually swings
Average temperatures in Crystal Lake run from 23°F in Jan up to 73°F in Jul, a 50.4°F seasonal swing, one of the widest gaps in this dataset.
Crystal Lake, month by month
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 32°F | 14°F | 1.97in | 10in |
| Feb | 35°F | 16°F | 1.84in | 9in |
| Mar | 47°F | 26°F | 2.51in | 4.4in |
| Apr | 59°F | 37°F | 3.76in | 1.2in |
| May | 71°F | 48°F | 4.98in | 0in |
| Jun | 80°F | 58°F | 5.26in | 0in |
| Jul | 84°F | 63°F | 3.9in | 0in |
| Aug | 82°F | 61°F | 3.81in | 0in |
| Sep | 74°F | 52°F | 3.54in | 0in |
| Oct | 62°F | 42°F | 3.2in | 0.2in |
| Nov | 48°F | 31°F | 2.48in | 1.6in |
| Dec | 36°F | 20°F | 2.1in | 8.7in |
If you're timing a visit, May, Jun, Jul, Aug, and Sep are Crystal Lake's mildest stretch; if you're moving there, you should plan around Jan's cold instead.
How wet Crystal Lake actually gets
Over a typical year, Crystal Lake sees about 39.35in of precipitation a year across roughly 110 days with measurable rain or snow, with 35.1in of snow a year.
Crystal Lake against the rest of the country
Out of 4876 cities scored here, Crystal Lake comes in at 3701; within IL alone it ranks 168 of 330. Population is about 41,513.
Checking the actual forecast
These figures come from Crystal Lake 4nw, IL US, the NOAA station 3.7 miles from Crystal Lake, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why this uses the nearest NOAA station · How the comfort score is calculated