Round Lake Park has cold, snowy winters and pleasant summers
A typical July afternoon reaches 83°, a January night drops to 15°, and about 43 inches of snow falls in a normal winter.
A year in Round Lake Park at a glance
Each month’s typical high and low, and what it brings.
What stands out about Round Lake Park’s climate
Read from where Round Lake Park sits among Illinois’s towns. The page puts what stands out first.
43 inches of snow, 37 of rain and melt
June is the wettest month and February the driest. Rain or snow falls on about 126 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
What a year in Round Lake Park feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 180 frost-free days a year
In half of years the last 32° night comes by April 24 and the first by October 23.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Living with Round Lake Park’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
180 frost-free days. The last frost comes by Apr 24 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 23.
About 43" a winter over 12 days with an inch or more, most in January. Snow covers the ground about 61 days a year.
Months averaging under 55° run from October through April. Heating is 90% of the year’s heating-and-cooling load.
About 10 days a year reach 90°, and July afternoons average 83°.
The nicest months are May, June, July, August and September. 0.3 miles of trails are waiting.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →Round Lake Park and its neighbors
Round Lake has the coldest January nights next door (15°) and Round Lake the hottest July afternoons (83°). Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Round Lake Park averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 57% of U.S. towns.
Change by month
How Round Lake Park compares
Against every U.S. town on TownTapestry, each counted once, with its place in Illinois.
Round Lake Park weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 15° | 1.9" | 15.7" | 12 | 23 | 12° – 34° |
| February | 34° | 18° | 1.8" | 8.0" | 9 | 15 | 14° – 37° |
| March | 45° | 27° | 2.3" | 5.8" | 11 | 7 | 28° – 51° |
| April | 57° | 36° | 3.9" | 1.5" | 12 | 1 | 39° – 53° |
| May | 69° | 47° | 4.2" | 0 | 13 | 0 | 52° – 65° |
| June | 79° | 57° | 4.5" | 0 | 10 | 0 | 64° – 73° |
| July | 83° | 62° | 3.6" | 0 | 10 | 0 | 67° – 79° |
| August | 81° | 61° | 3.8" | 0 | 9 | 0 | 65° – 76° |
| September | 74° | 53° | 3.5" | 0 | 9 | 0 | 58° – 68° |
| October | 62° | 42° | 3.2" | 0.1" | 10 | 0 | 47° – 57° |
| November | 47° | 31° | 2.5" | 3.1" | 11 | 3 | 31° – 48° |
| December | 35° | 21° | 2.0" | 9.2" | 11 | 13 | 15° – 38° |
| Year | 58° | 39° | 36.9" | 43.4" | 126 | 61 |
Heating and cooling a home in Round Lake Park
90% of the work is heating, so the furnace matters far more than the air conditioner.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 14° to 37°. June is the most reliable, staying within 9°.
Common questions about Round Lake Park’s climate
What is the coldest month in Round Lake Park?
January, with a typical high of 30° and a low of 15°.
What is the hottest month in Round Lake Park?
July, with a typical high of 83° and a low of 62°. About 10 days a year reach 90°.
How much snow does Round Lake Park get?
About 43 inches in a normal winter, most of it in January.
When is the first frost in Round Lake Park?
In half of years the first 32° night comes by October 23, and the last spring frost by April 24.
What is the rainiest month in Round Lake Park?
June, with 4.5 inches of rain and melted snow. The year totals 37 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Round Lake Park.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Round Lake Park itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Lake Villa 2ne, IL (6 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Today’s forecast: National Weather Service.