January in De Witt bites harder than in 72% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 85°. Winter and summer sit 68° apart. Its yearly precipitation falls short of 64% of U.S. towns. Tender plants can go out after about April 23; in half of years the first frost comes by October 13.
A year in De Witt at a glance
Each month’s typical high and low, and what it brings.
What stands out about De Witt’s climate
Compared with towns across the U.S., with De Witt’s place in Illinois beside it.
What a year in De Witt feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 170 frost-free days a year
In half of years the last 32° night comes by April 23 and the first by October 13. Frost and day counts come from NOAA’s station at Champaign 9 Sw, IL, 24 miles from the town’s center, at about the same height.
The 2023 USDA map puts De Witt’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −9°. 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 39 inches of rain a year
May is the wettest month and February the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in De Witt
88% 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 Champaign 9 Sw, IL.
Living with De Witt’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
170 frost-free days in zone 6a. The last frost comes by Apr 23 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 13.
Months with highs of 62–84° and lows of 40° or more: April, May, June, August, September and October.
Parks & trails →Of the yearly building losses FEMA expects in De Witt from natural hazards, river flooding is the largest share (36%); heat waves, cold waves, winter storms and ice storms together are 20%. Normals are averages; the hazards page covers the extremes.
Natural hazards →De Witt and similar climates
TownRatings has no climate map of the towns around De Witt yet.
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in De Witt averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.3°).
A smaller shift than in 58% 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 De Witt compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with De Witt’s place among Illinois’.
De Witt weather by month
Highs, lows and precipitation from NOAA’s grid at De Witt’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 34° | 18° | 2.2" | 19° – 37° |
| February | 39° | 21° | 1.9" | 18° – 40° |
| March | 51° | 31° | 2.7" | 34° – 55° |
| April | 64° | 40° | 3.8" | 44° – 58° |
| May | 74° | 52° | 4.5" | 57° – 71° |
| June | 83° | 61° | 4.5" | 68° – 76° |
| July | 85° | 64° | 4.1" | 69° – 81° |
| August | 84° | 62° | 3.5" | 68° – 79° |
| September | 79° | 54° | 3.2" | 61° – 71° |
| October | 66° | 43° | 3.3" | 50° – 60° |
| November | 51° | 32° | 3.0" | 34° – 49° |
| December | 38° | 23° | 2.3" | 17° – 40° |
| Year | 62° | 42° | 39.0" |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 17° to 40°. June is the most reliable, staying within 8°.
Where De Witt’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 De Witt’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Champaign 9 Sw, IL, 24 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 De Witt’s climate
What is the weather like in De Witt?
A typical July afternoon reaches 85°, a January night drops to 18°. Colder January nights than 72% of U.S. towns; hotter July afternoons than 51% of U.S. towns.
How cold does it get in De Witt in winter?
January nights average 18°. About 128 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 19°.
How hot does it get in De Witt?
July, with a typical high of 85° and a low of 64°. About 15 days a year reach 90° (Champaign 9 Sw, IL).
When is the first and last frost in De Witt?
In half of years the last spring frost (32°) comes by April 23 and the first fall frost by October 13, about 170 frost-free days, at Champaign 9 Sw, IL.
What growing zone is De Witt in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −9°.
What is the best time of year to visit De Witt?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is De Witt getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 58% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in De Witt.
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.