Mason City, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mason City, a city in Mason County, Illinois.
Today
87°F
Sunny
Sunny, with a high near 87. South wind around 6 mph.
7-day forecast for Mason City
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 87°F | Sunny | 6 mph S | 0% |
| Tonight | 67°F | Partly Cloudy | 5 mph SSE | 5% |
| Wednesday | 86°F | Mostly Sunny then Chance Showers And Thunderstorms | 7 mph S | 28% |
| Wednesday Night | 67°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 6 mph SSE | 79% |
| Thursday | 82°F | Showers And Thunderstorms then Chance Showers And Thunderstorms | 5 mph S | 79% |
| Thursday Night | 65°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 mph SSE | 18% |
| Friday | 84°F | Mostly Sunny | 2 mph SSW | 6% |
| Friday Night | 66°F | Slight Chance Showers And Thunderstorms | 2 mph S | 22% |
| Saturday | 87°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 2 to 6 mph SSW | 15% |
| Saturday Night | 70°F | Mostly Clear | 6 mph S | 9% |
| Sunday | 89°F | Sunny | 6 to 10 mph SSW | 6% |
| Sunday Night | 72°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 6 to 9 mph S | 15% |
| Monday | 89°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 9 mph SSW | 15% |
| Monday Night | 73°F | Slight Chance Showers And Thunderstorms | 8 mph SSW | 25% |
Forecast source: National Weather Service (api.weather.gov) for Mason City (40.202, -89.697). Updated through the day.
Growing snapshot for Mason City
Last spring frost
Apr 17
First fall frost
Oct 18
Growing season
182 days
Hardiness zone
6a
More local growing data for Mason City: nearby ZIP 62664 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mason City 4Se, Il (5.1 mi from Mason City). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.