Monticello, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Monticello, a city in Piatt County, Illinois.
Overnight
58°F
Light Rain Likely
Rain likely. Cloudy, with a low around 58. South wind 14 to 17 mph, with gusts as high as 26 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Monticello
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 58°F | Light Rain Likely | 14 to 17 mph S | 73% |
| Wednesday | 62°F | Slight Chance Drizzle | 13 to 16 mph SW | 20% |
| Wednesday Night | 46°F | Slight Chance Drizzle then Mostly Cloudy | 12 mph SW | 20% |
| Thursday | 61°F | Partly Sunny | 12 to 16 mph WSW | 13% |
| Thursday Night | 42°F | Mostly Cloudy | 9 mph NW | 11% |
| Friday | 53°F | Partly Sunny | 10 to 14 mph NNW | 9% |
| Friday Night | 33°F | Partly Cloudy | 5 to 10 mph NNW | 0% |
| Saturday | 53°F | Sunny | 7 mph NW | 0% |
| Saturday Night | 31°F | Partly Cloudy | 5 mph WNW | 1% |
| Sunday | 58°F | Sunny | 5 to 10 mph WNW | 1% |
| Sunday Night | 33°F | Clear | 3 to 7 mph W | 0% |
| Monday | 63°F | Sunny | 3 to 9 mph SW | 0% |
| Monday Night | 38°F | Clear | 7 mph SW | 0% |
| Tuesday | 66°F | Sunny | 7 mph WNW | 1% |
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 Nov 4, 2026.