Williamson County weather, town by town
17 places in Williamson County, Illinois, each with its own live forecast and radar, and where a station sits close enough, measured weather records.
B
C
E
F
H
J
M
P
S
W
Not your town? Type it above, or pick it below.
Measured at the NOAA stations serving these towns, daily records 1894 to 2026. Station extremes, not official state records.
Williamson County Weather Facts
Williamson County has 17 places on myweatherrock (8 villages, 6 cities, 3 census-designated places), each with its own live forecast, hourly timeline, ten day outlook and radar. The hottest day in the station records is 113°F at Carbondale Sewage Plt on August 9, 1930. The coldest night is -25°F at Carbondale Sewage Plt on January 11, 1977. The wettest day brought 7.51 inches of rain at Marion 4 Nne on May 11, 1996. The biggest single-day snow measured 17.52 inches at Marion 4 Nne on February 26, 1979. Those are station measurements from NOAA's daily records, 1894 to 2026, not official state records. By area the largest place is Marion, about 14 square miles.
About Williamson County weather
The map on the Now tab shows every Williamson County town's current temperature from our own server, one dot per town. Tap any dot, or type a town above, for that town's full forecast.
What the weather is usually like
Across the 17 Williamson County towns with station normals, the warmest month is July, when the day usually reaches 88°F, and the coldest is January, when the night usually falls to 24°F. May is the wettest, with rain on about 13 days. January nights run from about 22°F in Freeman Spur to 27°F in Creal Springs.
Means of the 1991 to 2020 station normals serving these towns, as published by NOAA; each town's page carries its own.
Where these numbers come from
- Current conditions and forecast: NOAA forecast grids decoded on our own server, corrected against the nearest reporting station and our own radar. Open-Meteo is consulted only as a fallback when our server is silent.
- Records: computed by myweatherrock from NOAA GHCN-Daily station records at the stations serving these towns. Measurements, not estimates.
- Warnings and alerts: the National Weather Service, passed through unchanged.
Williamson County weather records
Measured at the NOAA stations serving these towns, daily records 1894 to 2026. Station extremes, not official state records.
Common questions about Williamson County weather
- What is the hottest temperature recorded at a Williamson County station?
- 113°F at Carbondale Sewage Plt on August 9, 1930, in the NOAA daily station records myweatherrock holds (1894 to 2026).
- What is the coldest temperature recorded at a Williamson County station?
- -25°F at Carbondale Sewage Plt on January 11, 1977.
- What is the most rain a Williamson County station has measured in one day?
- 7.51 inches at Marion 4 Nne on May 11, 1996.
- What is the biggest one-day snowfall at a Williamson County station?
- 17.52 inches at Marion 4 Nne on February 26, 1979.
- How many Williamson County towns have a weather page here?
- 17: 8 villages, 6 cities, 3 census-designated places. Each page carries current conditions, the hourly timeline, the ten day outlook, radar, and where a station sits close enough, measured records.
- Where does the Williamson County forecast come from?
- NOAA forecast grids (the National Weather Service digital forecast, the National Blend of Models, HRRR and GFS) decoded on our own server, corrected against the nearest reporting station and our own radar. Open-Meteo is consulted only as a fallback when our server is silent.
Live radar
Current details
Water
Next few days
Hourly forecast
10-day forecast
The Rocktionary: every weather term, explained by a rock
Rockreation: pick a game
All records live on this device. The rock keeps no receipts. You keep them.
The weather you throw is whatever is outside right now.
A new Rocktoid every midnight. The rock reads a lot.
The rock's instrument panel
Remote Rocks: station a rock anywhere you love
Put a rock in Mom's yard, the lake house, a kid's college town. Each one stands in that sky and reports it here. Tap a rock for its forecast; the pencil renames it.
Tap me on the shoulder turns on browser notifications: when a warning or watch lands on one of your rocks, you get a notification, as long as the site is open in a tab somewhere.
Remote Rocks live on this device. We do not track you, so a rock you station on your phone will not appear on your computer or tablet, and the other way around. That is the privacy working, not a bug. Forecasts and alerts travel from here straight to the weather services, same as always.
Settings
Build