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Monmouth, IL Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Monmouth, a city in Warren County, Illinois.

This Afternoon
82°F
Mostly Cloudy
Mostly cloudy, with a high near 82. South wind 5 to 10 mph.

7-day forecast for Monmouth

WhenTempForecastWindPrecip
This Afternoon 82°F Mostly Cloudy 5 to 10 mph S 12%
Tonight 67°F Chance Showers And Thunderstorms then Showers And Thunderstorms Likely 0 to 5 mph E 65%
Sunday 72°F Showers And Thunderstorms 5 to 15 mph N 77%
Sunday Night 57°F Chance Showers And Thunderstorms then Showers And Thunderstorms Likely 10 to 15 mph NE 58%
Monday 64°F Rain Showers 15 mph NE 77%
Monday Night 54°F Rain Showers Likely 10 mph NE 73%
Tuesday 62°F Chance Rain Showers 10 mph NE 50%
Tuesday Night 50°F Mostly Cloudy 5 to 10 mph NE 7%
Wednesday 65°F Partly Sunny 5 to 10 mph NE 1%
Wednesday Night 52°F Partly Cloudy 0 to 5 mph NE 1%
Thursday 68°F Partly Sunny 5 mph NE 3%
Thursday Night 56°F Slight Chance Rain Showers 0 to 5 mph NE 15%
Friday 72°F Slight Chance Rain Showers 0 to 5 mph NE 15%
Friday Night 55°F Partly Cloudy 0 to 5 mph NE 6%

Forecast source: National Weather Service (api.weather.gov) for Monmouth (40.914, -90.643). Updated through the day.

Growing snapshot for Monmouth

Last spring frost
Apr 22
First fall frost
Oct 15
Growing season
174 days
Hardiness zone
5b

More local growing data for Monmouth: nearby ZIP 61462 weather · frost dates · planting calendar · Illinois frost dates

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Climate data from the nearest NOAA station, Monmouth, Il (2.5 mi from Monmouth). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.