Rock Creek, IL climate
Rock Creek has chilly winters and warm summers. A typical July afternoon reaches 86°, a January night drops to 17°, and about 22 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Rock Creek feels like
Winter
Spring
Summer
Fall
Rock Creek 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 | 33° | 17° | 1.7" | 7.2" | 7 | 18° – 37° |
| February | 38° | 21° | 1.9" | 5.7" | 6 | 17° – 40° |
| March | 50° | 31° | 2.6" | 2.3" | 6 | 33° – 55° |
| April | 63° | 41° | 4.0" | 0 | 10 | 44° – 59° |
| May | 73° | 53° | 5.2" | 0 | 10 | 57° – 71° |
| June | 82° | 62° | 5.0" | 0 | 10 | 69° – 75° |
| July | 86° | 66° | 4.1" | 0 | 7 | 70° – 82° |
| August | 84° | 64° | 3.8" | 0 | 7 | 68° – 79° |
| September | 78° | 56° | 3.7" | 0 | 6 | 61° – 71° |
| October | 65° | 44° | 3.2" | 0 | 7 | 49° – 60° |
| November | 50° | 32° | 2.5" | 0.8" | 7 | 33° – 51° |
| December | 38° | 22° | 2.0" | 5.5" | 7 | 15° – 39° |
| Year | 62° | 42° | 39.4" | 21.5" | 88 |
“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 Rock Creek
Rock Creek gets 39 inches of rain and melted snow a year. May is the wettest month and January the driest. Rain or snow falls on about 88 days a year.
About 194 frost-free days a year
In half of years the last 32° night comes by April 12 and the first one by October 25. That leaves about 194 frost-free days for gardens, longer than 68% of U.S. towns.
Heating and cooling a home in Rock Creek
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Rock Creek, 84% of that work is heating and 16% 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.
Rock Creek and its neighbors
Rock Creek borders 4 towns with climate data. January nights across them vary by 0.8°. Pontoosuc has the coldest January nights (17°) and Sonora the hottest July afternoons (86°). Rock Creek’s January low is 17° and its July high 86°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Rock Creek 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 Rock Creek averaged 0.7° warmer than the 1900s. The biggest change is in December (+1.9°). The shift is smaller than in 92% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Rock Creek’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 15° to 39°. June is the most reliable, staying within 6°.
Common questions about Rock Creek’s climate
What is the coldest month in Rock Creek?
January, with a typical high of 33° and a low of 17°.
What is the hottest month in Rock Creek?
July, with a typical high of 86° and a low of 66°. About 19 days a year reach 90°.
How much snow does Rock Creek get?
About 22 inches in a normal winter, most of it in January.
When is the first frost in Rock Creek?
In half of years the first 32° night comes by October 25, and the last spring frost by April 12.
What is the rainiest month in Rock Creek?
May, with 5.2 inches of rain and melted snow. The year totals 39 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Rock Creek itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Carthage, IL (8 mi, snow) and Ft Madison, IA (11 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.