Grafton, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grafton, a city in Jersey County, Illinois.
Overnight
65°F
Clear
Clear, with a low around 65. South wind around 2 mph.
7-day forecast for Grafton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 65°F | Clear | 2 mph S | 0% |
| Tuesday | 88°F | Patchy Fog then Sunny | 5 mph S | 0% |
| Tuesday Night | 69°F | Mostly Clear | 6 mph SE | 0% |
| Wednesday | 90°F | Mostly Sunny then Isolated Showers And Thunderstorms | 6 mph S | 15% |
| Wednesday Night | 71°F | Chance Showers And Thunderstorms | 7 mph S | 75% |
| Thursday | 86°F | Showers And Thunderstorms | 6 mph S | 75% |
| Thursday Night | 69°F | Slight Chance Showers And Thunderstorms | 2 to 6 mph SE | 20% |
| Friday | 86°F | Slight Chance Showers And Thunderstorms then Partly Sunny | 5 mph SW | 20% |
| Friday Night | 70°F | Chance Showers And Thunderstorms | 5 mph S | 26% |
| Saturday | 89°F | Chance Showers And Thunderstorms then Mostly Sunny | 6 mph S | 26% |
| Saturday Night | 73°F | Mostly Clear | 6 mph S | 6% |
| Sunday | 92°F | Sunny | 6 to 9 mph S | 5% |
| Sunday Night | 75°F | Mostly Clear | 8 mph S | 5% |
| Monday | 93°F | Mostly Sunny | 6 to 9 mph SW | 5% |
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 Aug 4, 2026.