Photo: Anonymous · CC BY-SA 4.0Wilmington Township’s winters are colder but less snowy than most of the U.S.
A typical July afternoon reaches 85°, a January night drops to 17°, and about 18 inches of snow falls in a normal winter.
A year in Wilmington Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Wilmington Township’s climate
Compared with towns across the U.S., with Wilmington Township’s place in Illinois beside it.
What a year in Wilmington Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 191 frost-free days a year
In half of years the last 32° night comes by April 16 and the first by October 26. Frost and day counts come from NOAA’s station at Channahon Dresden Isl Dam, IL, 7 miles from the town’s center, at about the same height.
The 2023 USDA map puts Wilmington Township’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −11°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 18 inches of snow a winter
Snow, measured at Channahon Dresden Isl Dam, IL, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 38 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 120 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Wilmington Township
86% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Channahon Dresden Isl Dam, IL.
Living with Wilmington Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
191 frost-free days in zone 5b. The last frost comes by Apr 16 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 26.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 12 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Wilmington Township from natural hazards, river flooding is the largest share (67%); heat waves, cold waves, winter storms and ice storms together are 15%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Wilmington Township and its neighbors
Every town next door is within a degree of Wilmington Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Wilmington Township’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Wilmington Township, IL | 17° | 85° | 38" | 18" |
| Van Wert, OH | 19° | 84° | 39" | 17" |
| Burlington, IA | 16° | 86° | 38" | 22" |
| Bluffton, IN | 19° | 84° | 41" | 23" |
| Kirksville, MO | 17° | 86° | 41" | 19" |
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 Wilmington Township averaged 1.4° warmer than the 1900s. The biggest change is in December (+2.6°).
A bigger shift than in 54% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Wilmington Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Wilmington Township’s place among Illinois’.
Wilmington Township weather by month
Highs, lows and precipitation from NOAA’s grid at Wilmington Township’s center; snow, wet days and snow on the ground from Channahon Dresden Isl Dam, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 32° | 17° | 2.1" | 6.4" | 12 | 15° – 37° |
| February | 36° | 20° | 1.8" | 5.2" | 10 | 15° – 40° |
| March | 49° | 30° | 2.4" | 0.4" | 11 | 30° – 55° |
| April | 62° | 39° | 3.7" | 0.0" | 11 | 42° – 57° |
| May | 73° | 51° | 4.7" | 0.0" | 11 | 55° – 68° |
| June | 82° | 60° | 4.4" | 0.0" | 10 | 67° – 75° |
| July | 85° | 64° | 4.1" | 0.0" | 9 | 69° – 81° |
| August | 83° | 62° | 3.9" | 0.0" | 9 | 67° – 78° |
| September | 77° | 55° | 3.3" | 0.0" | 8 | 60° – 70° |
| October | 65° | 43° | 3.2" | 0.0" | 9 | 49° – 59° |
| November | 49° | 32° | 2.5" | 0.3" | 10 | 33° – 49° |
| December | 37° | 22° | 2.1" | 6.1" | 12 | 15° – 40° |
| Year | 61° | 41° | 38.1" | 18.4" | 120 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 30° to 55°. June is the most reliable, staying within 8°.
Where Wilmington Township’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Wilmington Township’s center.
- Snow: Channahon Dresden Isl Dam, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Channahon Dresden Isl Dam, IL, 7 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Wilmington Township’s climate
What is the weather like in Wilmington Township?
A typical July afternoon reaches 85°, a January night drops to 17°, and about 18 inches of snow falls in a normal winter. Colder January nights than 77% of U.S. towns; cooler July afternoons than 53% of U.S. towns.
How cold does it get in Wilmington Township in winter?
January nights average 17°. About 127 nights a year reach 32° or below and 7 reach 0° or below. In the coldest January of the last 30 years the month averaged 15°.
How much snow does Wilmington Township get?
About 18 inches in a normal winter at Channahon Dresden Isl Dam, IL, most of it in January and December.
How hot does it get in Wilmington Township?
July, with a typical high of 85° and a low of 64°. About 21 days a year reach 90° (Channahon Dresden Isl Dam, IL).
When is the first and last frost in Wilmington Township?
In half of years the last spring frost (32°) comes by April 16 and the first fall frost by October 26, about 191 frost-free days, at Channahon Dresden Isl Dam, IL.
What growing zone is Wilmington Township in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −11°.
What is the best time of year to visit Wilmington Township?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Wilmington Township getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 54% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Wilmington Township.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.