Grafton, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grafton, a city in Jersey County, Illinois.
Tonight
73°F
Partly Cloudy
Partly cloudy, with a low around 73. Southeast wind around 6 mph.
7-day forecast for Grafton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 73°F | Partly Cloudy | 6 mph SE | 10% |
| Saturday | 97°F | Mostly Sunny | 5 to 9 mph SW | 6% |
| Saturday Night | 73°F | Partly Cloudy | 6 mph SW | 8% |
| Sunday | 91°F | Chance Rain Showers then Chance Showers And Thunderstorms | 3 to 8 mph NW | 33% |
| Sunday Night | 66°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 7 to 10 mph N | 67% |
| Monday | 77°F | Showers And Thunderstorms Likely | 7 to 13 mph NE | 67% |
| Monday Night | 59°F | Showers And Thunderstorms Likely | 8 to 13 mph N | 64% |
| Tuesday | 71°F | Slight Chance Rain Showers then Mostly Cloudy | 13 mph N | 23% |
| Tuesday Night | 54°F | Mostly Cloudy | 7 to 13 mph N | 5% |
| Wednesday | 74°F | Mostly Sunny | 7 to 10 mph N | 1% |
| Wednesday Night | 55°F | Partly Cloudy | 3 to 9 mph N | 1% |
| Thursday | 75°F | Mostly Sunny | 5 to 8 mph N | 4% |
| Thursday Night | 58°F | Partly Cloudy | 3 to 7 mph NE | 3% |
| Friday | 76°F | Mostly Sunny | 5 to 8 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov) for Grafton (38.976, -90.426). Updated through the day.
Growing snapshot for Grafton
Last spring frost
Apr 5
First fall frost
Oct 27
Growing season
203 days
Hardiness zone
6b
More local growing data for Grafton: nearby ZIP 62037 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, St Charles Co Ap, Mo (6 mi from Grafton). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.