Rockwood has chilly winters and warm summers
A typical July afternoon reaches 88°, a January night drops to 24°, and about 12 inches of snow falls in a normal winter.
A year in Rockwood at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rockwood’s climate
Read from where Rockwood sits among Illinois’s towns. The page puts what stands out first.
About 182 frost-free days a year
In half of years the last 32° night comes by April 19 and the first by October 20.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
What a year in Rockwood feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
12 inches of snow, 45 of rain and melt
May is the wettest month and February the driest. Rain or snow falls on about 101 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Living with Rockwood’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
182 frost-free days. The last frost comes by Apr 19 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 20.
About 12" a winter over 4 days with an inch or more, most in January.
Months averaging under 55° run from November through March. Heating is 79% of the year’s heating-and-cooling load.
About 39 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 Rockwood averaged 1.0° warmer than the 1900s. The biggest change is in February (+1.9°).
A smaller shift than in 73% of U.S. towns.
Change by month
How Rockwood compares
Against every U.S. town on TownTapestry, each counted once, with its place in Illinois.
Rockwood 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 | 41° | 24° | 2.9" | 3.7" | 8 | 26° – 43° |
| February | 46° | 28° | 2.8" | 3.7" | 8 | 26° – 45° |
| March | 56° | 36° | 4.0" | 1.1" | 10 | 39° – 59° |
| April | 68° | 45° | 5.2" | 0 | 10 | 49° – 62° |
| May | 77° | 55° | 5.2" | 0 | 11 | 60° – 72° |
| June | 85° | 64° | 4.3" | 0 | 9 | 69° – 80° |
| July | 88° | 68° | 3.9" | 0 | 8 | 73° – 84° |
| August | 87° | 65° | 3.2" | 0 | 8 | 71° – 83° |
| September | 81° | 57° | 3.0" | 0 | 7 | 66° – 76° |
| October | 70° | 46° | 3.4" | 0.1" | 8 | 54° – 63° |
| November | 55° | 36° | 4.1" | 0.5" | 8 | 38° – 52° |
| December | 45° | 28° | 3.1" | 2.9" | 8 | 23° – 46° |
| Year | 67° | 46° | 45.0" | 12.0" | 101 |
Heating and cooling a home in Rockwood
79% 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 23° to 46°. October is the most reliable, staying within 9°.
Common questions about Rockwood’s climate
What is the coldest month in Rockwood?
January, with a typical high of 41° and a low of 24°.
What is the hottest month in Rockwood?
July, with a typical high of 88° and a low of 68°. About 39 days a year reach 90°.
How much snow does Rockwood get?
About 12 inches in a normal winter, most of it in January.
When is the first frost in Rockwood?
In half of years the first 32° night comes by October 20, and the last spring frost by April 19.
What is the rainiest month in Rockwood?
May, with 5.2 inches of rain and melted snow. The year totals 45 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rockwood.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Rockwood itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Chester, IL (9 mi, snow) and Perryville Wtp, MO (14 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.