St. Augustine, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Augustine, a village in Knox County, Illinois.
Overnight
51°F
Slight Chance Light Rain
A slight chance of rain before 4am. Mostly cloudy. Low around 51, with temperatures rising to around 56 overnight. South southwest wind 8 to 12 mph, with gusts as high as 22 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for St. Augustine
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 51°F | Slight Chance Light Rain | 8 to 12 mph SSW | 22% |
| Wednesday | 57°F | Slight Chance Rain Showers then Mostly Cloudy | 13 to 16 mph SW | 17% |
| Wednesday Night | 44°F | Mostly Cloudy | 10 mph SW | 5% |
| Thursday | 57°F | Mostly Cloudy then Slight Chance Light Rain | 8 to 13 mph W | 18% |
| Thursday Night | 41°F | Chance Light Rain | 3 to 7 mph NW | 30% |
| Friday | 53°F | Mostly Cloudy | 6 to 9 mph N | 14% |
| Friday Night | 34°F | Mostly Cloudy | 0 to 5 mph N | 1% |
| Saturday | 53°F | Mostly Sunny | 0 to 3 mph NW | 2% |
| Saturday Night | 34°F | Partly Cloudy | 2 mph W | 1% |
| Sunday | 59°F | Sunny | 2 to 8 mph WNW | 11% |
| Sunday Night | 35°F | Mostly Clear | 5 mph W | 3% |
| Monday | 64°F | Sunny | 2 to 10 mph SW | 2% |
| Monday Night | 40°F | Mostly Clear | 2 to 6 mph W | 0% |
| Tuesday | 65°F | Sunny | 5 mph NW | 0% |
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
Nearby towns & communities
Abingdon
Altona
East Galesburg
Galesburg
Gilson
Henderson
Knoxville
Maquon
Nekoma
Oak Run
Oneida
Rio
Victoria
Wataga
Williamsfield
Yates City
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 Nov 4, 2026.