Johnsonville has chilly winters and warm summers
A typical July afternoon reaches 88°, a January night drops to 23°, and about 12 inches of snow falls in a normal winter.
A year in Johnsonville at a glance
Each month’s typical high and low, and what it brings.
What stands out about Johnsonville’s climate
Read from where Johnsonville sits among Illinois’s towns. The page puts what stands out first.
12 inches of snow, 46 of rain and melt
May is the wettest month and February the driest. Rain or snow falls on about 82 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
What a year in Johnsonville feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 196 frost-free days a year
In half of years the last 32° night comes by April 10 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 Johnsonville’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
196 frost-free days. The last frost comes by Apr 10 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 12" a winter over 6 days with an inch or more, most in December.
Months averaging under 55° run from November through March. Heating is 77% of the year’s heating-and-cooling load.
About 35 days a year reach 90°, and July afternoons average 88°.
The nicest months are April, May, September and October.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →Warmer than it used to be
The last 30 years in Johnsonville averaged 1.1° warmer than the 1900s. The biggest change is in February (+2.1°).
A smaller shift than in 65% of U.S. towns.
Change by month
How Johnsonville compares
Against every U.S. town on TownTapestry, each counted once, with its place in Illinois.
Johnsonville 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 39° | 23° | 3.3" | 3.4" | 6 | 25° – 41° |
| February | 44° | 27° | 2.6" | 2.9" | 5 | 25° – 45° |
| March | 55° | 35° | 3.9" | 1.7" | 8 | 37° – 58° |
| April | 67° | 45° | 5.0" | 0 | 8 | 49° – 61° |
| May | 76° | 55° | 5.2" | 0 | 10 | 60° – 72° |
| June | 85° | 63° | 5.0" | 0 | 9 | 69° – 78° |
| July | 88° | 67° | 4.1" | 0 | 8 | 71° – 84° |
| August | 86° | 65° | 3.4" | 0 | 6 | 71° – 81° |
| September | 80° | 57° | 3.5" | 0 | 5 | 64° – 75° |
| October | 69° | 46° | 3.5" | 0 | 6 | 52° – 62° |
| November | 54° | 36° | 4.0" | 0.2" | 6 | 38° – 51° |
| December | 43° | 27° | 3.2" | 3.7" | 6 | 21° – 45° |
| Year | 65° | 45° | 46.5" | 11.9" | 82 |
Heating and cooling a home in Johnsonville
77% of the work is heating.
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. December swings the most: from 1991 to 2020 its average ranged from 21° to 45°. June is the most reliable, staying within 9°.
Common questions about Johnsonville’s climate
What is the coldest month in Johnsonville?
January, with a typical high of 39° and a low of 23°.
What is the hottest month in Johnsonville?
July, with a typical high of 88° and a low of 67°. About 35 days a year reach 90°.
How much snow does Johnsonville get?
About 12 inches in a normal winter, most of it in December.
When is the first frost in Johnsonville?
In half of years the first 32° night comes by October 23, and the last spring frost by April 10.
What is the rainiest month in Johnsonville?
May, with 5.2 inches of rain and melted snow. The year totals 46 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Johnsonville.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Johnsonville itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Cisne 2 S, IL (7 mi, snow) and Flora 5 Nw, IL (13 mi, frost, heat and degree days). 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.