Mount Prospect, IL Weather & Growing Conditions
This Afternoon
71°F
Chance Rain
A chance of rain before 3pm, then a chance of rain and a slight chance of thunderstorms. Mostly cloudy. High near 71, with temperatures falling to around 69 in the afternoon. South wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 71°F | Chance Rain | 15 to 20 mph S | 41% |
| Tonight | 61°F | Rain | 15 mph S | 81% |
| Wednesday | 64°F | Rain Likely | 15 mph SSW | 58% |
| Wednesday Night | 48°F | Slight Chance Rain then Mostly Cloudy | 15 mph SW | 18% |
| Thursday | 57°F | Chance Rain | 10 to 15 mph WSW | 31% |
| Thursday Night | 43°F | Chance Rain | 5 to 10 mph WNW | 53% |
| Friday | 52°F | Chance Rain | 10 to 15 mph N | 33% |
| Friday Night | 38°F | Mostly Cloudy | 5 to 10 mph NNW | 11% |
| Saturday | 52°F | Mostly Sunny | 5 mph WNW | 8% |
| Saturday Night | 37°F | Partly Cloudy | 0 to 5 mph WSW | 7% |
| Sunday | 57°F | Mostly Sunny then Slight Chance Rain | 5 to 10 mph W | 17% |
| Sunday Night | 38°F | Mostly Clear | 5 mph WNW | 9% |
| Monday | 60°F | Sunny | 5 to 10 mph WSW | 4% |
| Monday Night | 42°F | Partly Cloudy | 5 to 10 mph W | 2% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Mount Prospect, IL
Last spring frost
Apr 19
First fall frost
Oct 26
Growing season
190 days
Hardiness zone
6a
Explore more for Mount Prospect, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Chicago Palwaukee Ap, Il (4.1 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.