Thomson, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Thomson, a village in Carroll County, Illinois.
Tonight
64°F
Mostly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms between midnight and 4am, then showers and thunderstorms. Some of the storms could produce heavy rain. Mostly cloudy. Low around 64, with temperatures rising to around 66 overnight. East wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast for Thomson
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 64°F | Mostly Cloudy then Chance Showers And Thunderstorms | 5 to 10 mph E | 76% |
| Saturday | 79°F | Showers And Thunderstorms | 5 to 10 mph S | 79% |
| Saturday Night | 62°F | Showers And Thunderstorms | 5 to 10 mph N | 76% |
| Sunday | 69°F | Rain Showers | 10 to 15 mph NE | 76% |
| Sunday Night | 55°F | Rain Showers Likely | 10 to 15 mph NE | 62% |
| Monday | 64°F | Chance Rain Showers | 10 to 15 mph NE | 48% |
| Monday Night | 51°F | Chance Rain Showers | 10 to 15 mph NE | 45% |
| Tuesday | 63°F | Chance Rain Showers | 10 to 15 mph NE | 33% |
| Tuesday Night | 48°F | Partly Cloudy | 5 to 10 mph NE | 7% |
| Wednesday | 67°F | Mostly Sunny | 5 to 10 mph NE | 3% |
| Wednesday Night | 51°F | Partly Cloudy | 0 to 5 mph NE | 2% |
| Thursday | 68°F | Mostly Sunny | 0 to 5 mph NE | 5% |
| Thursday Night | 53°F | Partly Cloudy | 0 to 5 mph NE | 5% |
| Friday | 70°F | Mostly Sunny | 0 to 5 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Thomson (41.975, -90.112). Updated through the day.
Growing snapshot for Thomson
Last spring frost
Apr 13
First fall frost
Oct 26
Growing season
195 days
Hardiness zone
5b
More local growing data for Thomson: nearby ZIP 61285 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Fulton L&D #13, Il (7.6 mi from Thomson). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.