Round Lake, IL Weather & Climate Normals
What a normal year in Round Lake actually looks like
On the 30-year record NOAA keeps for Round Lake, IL, the comfort score comes out to 43/100, 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 Round Lake's weather actually swings
Average temperatures in Round Lake run from 21°F in Jan up to 72°F in Jul, a 51°F seasonal swing, one of the widest gaps in this dataset.
Round Lake, month by month
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 29°F | 14°F | 1.76in | 11in |
| Feb | 33°F | 16°F | 1.93in | 12.8in |
| Mar | 44°F | 26°F | 2.49in | 5.3in |
| Apr | 57°F | 36°F | 3.95in | 1.8in |
| May | 68°F | 47°F | 4.57in | 0in |
| Jun | 78°F | 58°F | 4.38in | 0in |
| Jul | 82°F | 62°F | 4.01in | 0in |
| Aug | 81°F | 61°F | 4.19in | 0in |
| Sep | 74°F | 53°F | 3.38in | 0in |
| Oct | 61°F | 42°F | 3.2in | 0in |
| Nov | 47°F | 30°F | 2.47in | 2.5in |
| Dec | 34°F | 20°F | 2.12in | 9.7in |
If you're timing a visit, May, Jun, Jul, Aug, and Sep are Round Lake's mildest stretch; if you're moving there, you should plan around Jan's cold instead.
How wet Round Lake actually gets
Over a typical year, Round Lake sees about 38.45in of precipitation a year across roughly 128 days with measurable rain or snow, with 43.1in of snow a year.
Round Lake against the rest of the country
Out of 4876 cities scored here, Round Lake comes in at 4016; within IL alone it ranks 249 of 330. Population is about 18,654.
Checking the actual forecast
These figures come from Mundelein 4 Wsw, IL US, the NOAA station 6.2 miles from Round Lake, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why some cities show no snow or rain figure · What a 30-year climate normal actually is