Harman US

Alpha, IL Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Alpha, a village in Henry County, Illinois.

Tonight
68°F
Mostly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 2am. Mostly cloudy, with a low around 68. Southeast wind 10 to 15 mph. Chance of precipitation is 40%.

7-day forecast for Alpha

WhenTempForecastWindPrecip
Tonight 68°F Mostly Cloudy then Chance Showers And Thunderstorms 10 to 15 mph SE 44%
Saturday 83°F Chance Showers And Thunderstorms then Showers And Thunderstorms Likely 5 to 10 mph S 55%
Saturday Night 65°F Chance Showers And Thunderstorms then Showers And Thunderstorms 5 mph N 77%
Sunday 72°F Showers And Thunderstorms 5 to 15 mph NE 77%
Sunday Night 58°F Showers And Thunderstorms Likely 15 mph NE 65%
Monday 64°F Showers And Thunderstorms Likely 15 to 20 mph NE 62%
Monday Night 53°F Chance Rain Showers 15 mph NE 48%
Tuesday 63°F Chance Rain Showers 15 mph NE 39%
Tuesday Night 49°F Mostly Cloudy 5 to 15 mph NE 5%
Wednesday 67°F Mostly Sunny 10 mph NE 2%
Wednesday Night 52°F Partly Cloudy 5 mph NE 2%
Thursday 68°F Mostly Sunny 5 mph NE 4%
Thursday Night 54°F Partly Cloudy 0 to 5 mph NE 5%
Friday 70°F Mostly Sunny 5 mph NE 5%

Forecast source: National Weather Service (api.weather.gov) for Alpha (41.192, -90.380). Updated through the day.

Growing snapshot for Alpha

Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
165 days
Hardiness zone
5b

More local growing data for Alpha: nearby ZIP 61413 weather · frost dates · planting calendar · Illinois frost dates

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Climate data from the nearest NOAA station, Altona, Il (11.7 mi from Alpha). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.