Monticello, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Monticello, a city in Piatt County, Illinois.
This Afternoon
86°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Mostly cloudy, with a high near 86. South southwest wind around 7 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Monticello
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 86°F | Chance Showers And Thunderstorms | 7 mph SSW | 32% |
| Tonight | 69°F | Mostly Cloudy | 6 mph S | 13% |
| Sunday | 82°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 6 to 13 mph NNE | 33% |
| Sunday Night | 59°F | Chance Showers And Thunderstorms | 10 to 14 mph NE | 43% |
| Monday | 69°F | Rain Showers Likely | 10 to 16 mph ENE | 66% |
| Monday Night | 54°F | Chance Rain Showers | 12 to 15 mph ENE | 48% |
| Tuesday | 66°F | Chance Rain Showers | 16 mph NE | 46% |
| Tuesday Night | 52°F | Mostly Cloudy | 8 to 16 mph NNE | 11% |
| Wednesday | 68°F | Partly Sunny | 13 mph NNE | 7% |
| Wednesday Night | 53°F | Partly Cloudy | 6 to 13 mph NNE | 0% |
| Thursday | 72°F | Partly Sunny | 9 mph NNE | 1% |
| Thursday Night | 55°F | Mostly Cloudy | 5 to 9 mph NNE | 3% |
| Friday | 74°F | Partly Sunny | 6 to 9 mph NNE | 4% |
| Friday Night | 54°F | Partly Cloudy | 8 mph NE | 4% |
Forecast source: National Weather Service (api.weather.gov) for Monticello (40.034, -88.574). Updated through the day.
Growing snapshot for Monticello
Last spring frost
Apr 23
First fall frost
Oct 13
Growing season
170 days
Hardiness zone
6a
More local growing data for Monticello: nearby ZIP 61856 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Champaign 9 Sw, Il (11.3 mi from Monticello). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.