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
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| 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
Nearby towns & communities
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.