Decker, IL climate
Decker has chilly winters and warm summers. A typical July afternoon reaches 87°, a January night drops to 23°, and about 11 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Decker feels like
Winter
Spring
Summer
Fall
Decker 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 | 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 | 10 | 0 | 49° – 61° |
| May | 76° | 55° | 5.2" | 0 | 11 | 0 | 60° – 73° |
| June | 85° | 63° | 5.0" | 0 | 9 | 0 | 69° – 78° |
| July | 87° | 67° | 4.4" | 0 | 7 | 0 | 72° – 84° |
| August | 86° | 65° | 3.4" | 0 | 7 | 0 | 71° – 81° |
| September | 81° | 57° | 3.5" | 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 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Decker
Decker gets 47 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 101 days a year. Snow covers the ground about 7 days of the year.
About 189 frost-free days a year
In half of years the last 32° night comes by April 15 and the first one by October 23. That leaves about 189 frost-free days for gardens, longer than 63% of U.S. towns.
Heating and cooling a home in Decker
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Decker, 81% of that work is heating and 19% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Decker and its neighbors
Decker borders 4 towns with climate data. January nights across them vary by 0.9°. Noble has the coldest January nights (23°) and Mount Erie the hottest July afternoons (88°). Decker’s January low is 23° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Decker compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Decker averaged 1.0° warmer than the 1900s. The biggest change is in February (+1.8°). The shift is smaller than in 71% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Decker’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 21° to 44°. June is the most reliable, staying within 9°.
Common questions about Decker’s climate
What is the coldest month in Decker?
January, with a typical high of 39° and a low of 23°.
What is the hottest month in Decker?
July, with a typical high of 87° and a low of 67°. About 32 days a year reach 90°.
How much snow does Decker get?
About 11 inches in a normal winter, most of it in January.
When is the first frost in Decker?
In half of years the first 32° night comes by October 23, and the last spring frost by April 15.
What is the rainiest month in Decker?
May, with 5.2 inches of rain and melted snow. The year totals 47 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Decker itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Clay City 6sse, IL (6 mi, snow) and Olney 2s, IL (8 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.