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St. Augustine, IL Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for St. Augustine, a village in Knox County, Illinois.

This Afternoon
84°F
Mostly Cloudy
Mostly cloudy, with a high near 84. South southwest wind around 8 mph, with gusts as high as 16 mph.

7-day forecast for St. Augustine

WhenTempForecastWindPrecip
This Afternoon 84°F Mostly Cloudy 8 mph SSW 7%
Tonight 67°F Chance Showers And Thunderstorms 2 to 8 mph SSW 60%
Sunday 74°F Showers And Thunderstorms Likely 3 to 13 mph N 67%
Sunday Night 58°F Chance Showers And Thunderstorms then Showers And Thunderstorms Likely 10 to 14 mph NE 59%
Monday 65°F Showers And Thunderstorms 13 mph ENE 75%
Monday Night 54°F Rain Showers Likely 10 mph NE 66%
Tuesday 63°F Chance Rain Showers 12 mph NE 53%
Tuesday Night 50°F Mostly Cloudy 3 to 9 mph NNE 8%
Wednesday 66°F Partly Sunny 5 to 8 mph NNE 2%
Wednesday Night 52°F Partly Cloudy 1 to 6 mph NNE 1%
Thursday 69°F Partly Sunny 1 to 5 mph NE 3%
Thursday Night 55°F Slight Chance Rain Showers 0 to 3 mph NE 15%
Friday 73°F Slight Chance Rain Showers then Partly Sunny 1 to 5 mph NE 15%
Friday Night 55°F Partly Cloudy 3 mph NE 7%

Forecast source: National Weather Service (api.weather.gov) for St. Augustine (40.721, -90.407). Updated through the day.

Growing snapshot for St. Augustine

Last spring frost
Apr 22
First fall frost
Oct 19
Growing season
177 days
Hardiness zone
5b

More local growing data for St. Augustine: nearby ZIP 61474 weather · frost dates · planting calendar · Illinois frost dates

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Climate data from the nearest NOAA station, Avon, Il (6.1 mi from St. Augustine). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.