Herrin, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Herrin, a city in Williamson County, Illinois.
This Afternoon
100°F
Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms. Sunny. High near 100, with temperatures falling to around 98 in the afternoon. Heat index values as high as 107. Southwest wind around 6 mph. Chance of precipitation is 20%.
7-day forecast for Herrin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 100°F | Slight Chance Showers And Thunderstorms | 6 mph SW | 24% |
| Tonight | 72°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 mph SSE | 23% |
| Saturday | 99°F | Sunny | 2 to 7 mph SW | 4% |
| Saturday Night | 73°F | Partly Cloudy | 5 mph SSW | 1% |
| Sunday | 98°F | Sunny | 3 to 8 mph WSW | 7% |
| Sunday Night | 70°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph N | 16% |
| Monday | 88°F | Chance Showers And Thunderstorms | 5 to 10 mph N | 46% |
| Monday Night | 62°F | Chance Showers And Thunderstorms | 6 to 12 mph NNE | 46% |
| Tuesday | 77°F | Slight Chance Showers And Thunderstorms then Partly Sunny | 8 to 12 mph N | 17% |
| Tuesday Night | 57°F | Partly Cloudy | 5 to 12 mph N | 7% |
| Wednesday | 77°F | Mostly Sunny | 6 to 10 mph N | 3% |
| Wednesday Night | 57°F | Partly Cloudy | 3 to 8 mph NNE | 2% |
| Thursday | 77°F | Mostly Sunny | 3 to 9 mph N | 2% |
| Thursday Night | 58°F | Partly Cloudy | 3 to 8 mph NNE | 2% |
Forecast source: National Weather Service (api.weather.gov) for Herrin (37.798, -89.031). Updated through the day.
Growing snapshot for Herrin
Last spring frost
Apr 9
First fall frost
Oct 22
Growing season
195 days
Hardiness zone
7a
More local growing data for Herrin: nearby ZIP 62948 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Carbondale Sewage Plt, Il (9.8 mi from Herrin). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.