The climate in Decker Township sits close to the middle of U.S. towns
In July the day’s top temperature is typically 87°. Its yearly precipitation tops that of 69% of U.S. towns. The latest 30-year average runs 1.0° warmer than 1901–2000’s, with February up the most. The outdoor season, with highs of 67–81°, runs through April, May, September and October.
A year in Decker Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Decker Township’s climate
Compared with towns across the U.S., with Decker Township’s place in Illinois beside it.
What a year in Decker Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 189 frost-free days a year
In half of years the last 32° night comes by April 15 and the first by October 23. Frost and day counts come from NOAA’s station at Olney 2s, IL, 8 miles from the town’s center, at about the same height.
The 2023 USDA map puts Decker Township’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −2°. 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 11 inches of snow a winter
Snow, measured at Clay City 6sse, IL, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 47 inches a year; 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
Heating and cooling a home in Decker Township
81% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Olney 2s, IL.
Living with Decker Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
189 frost-free days in zone 6b. The last frost comes by Apr 15 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.
Months with highs of 62–84° and lows of 40° or more: April, May, September and October. 2.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Decker Township from natural hazards, river flooding is the largest share (36%); heat waves, cold waves, winter storms and ice storms together are 9%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Decker Township and its neighbors
Every town next door is within a degree of Decker Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Decker 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 |
|---|---|---|---|---|
| Decker Township, IL | 23° | 87° | 47" | 11" |
| Collegeville, PA | 23° | 88° | 47" | 13" |
| Lebanon, MO | 23° | 88° | 45" | 8.3" |
| Huntington, WV | 25° | 87° | 46" | 10" |
| Hockessin, DE | 24° | 86° | 48" | 12" |
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 Decker Township averaged 1.0° warmer than the 1900s. The biggest change is in February (+1.8°).
A smaller shift than in 79% 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 Decker Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Decker Township’s place among Illinois’.
Decker Township weather by month
Highs, lows and precipitation from NOAA’s grid at Decker Township’s center; snow, wet days and snow on the ground from Clay City 6sse, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 39° | 23° | 3.3" | 3.4" | 9 | 3 | 24° – 41° |
| February | 44° | 26° | 2.5" | 2.2" | 8 | 2 | 23° – 44° |
| March | 54° | 35° | 3.9" | 0.9" | 10 | 1 | 37° – 59° |
| April | 67° | 44° | 5.0" | 0.0" | 10 | 0 | 49° – 61° |
| May | 76° | 55° | 5.2" | 0.0" | 11 | 0 | 60° – 73° |
| June | 85° | 63° | 5.0" | 0.0" | 9 | 0 | 69° – 78° |
| July | 87° | 67° | 4.4" | 0.0" | 7 | 0 | 72° – 84° |
| August | 86° | 65° | 3.4" | 0.0" | 7 | 0 | 71° – 81° |
| September | 81° | 57° | 3.5" | 0.0" | 6 | 0 | 65° – 74° |
| October | 69° | 46° | 3.6" | 0.1" | 7 | 0 | 52° – 62° |
| November | 54° | 35° | 4.0" | 0.9" | 8 | 0 | 37° – 51° |
| December | 43° | 27° | 3.1" | 3.1" | 9 | 2 | 21° – 44° |
| Year | 65° | 45° | 46.9" | 10.6" | 101 | 7 |
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 44°. June is the most reliable, staying within 9°.
Where Decker 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 Decker Township’s center.
- Snow: Clay City 6sse, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Olney 2s, IL, 8 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 Decker Township’s climate
What is the weather like in Decker Township?
A typical July afternoon reaches 87°, a January night drops to 23°, and about 11 inches of snow falls in a normal winter. Milder January nights than 55% of U.S. towns; hotter July afternoons than 64% of U.S. towns.
How cold does it get in Decker Township in winter?
January nights average 23°. About 105 nights a year reach 32° or below and 3 reach 0° or below. In the coldest January of the last 30 years the month averaged 24°.
How much snow does Decker Township get?
About 11 inches in a normal winter at Clay City 6sse, IL, most of it in January and December, with snow on the ground about 7 days a year.
How hot does it get in Decker Township?
July, with a typical high of 87° and a low of 67°. About 32 days a year reach 90° (Olney 2s, IL).
When is the first and last frost in Decker Township?
In half of years the last spring frost (32°) comes by April 15 and the first fall frost by October 23, about 189 frost-free days, at Olney 2s, IL.
What growing zone is Decker Township in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −2°.
What is the best time of year to visit Decker Township?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Decker Township getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 79% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Decker 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.