Mason City, Iowa Weather
Hourly forecast in Mason City
16-day forecast for Mason City
Check any date
Mason City air quality & conditions
Air quality index
Today's outlook for Mason City
Loading today's outlook…
Explore nearby
Weather articles
Weather news
Climate of Mason City: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Mason City, with average daytime highs around 28°C. January is the coolest, when nights typically fall to about -13°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 41°C, so the seasons feel very different from each other.
The area receives about 940 mm of rain in a typical year. Most of it falls from May to August (around 51% of the yearly total), and June is the wettest month at roughly 146 mm.
For outdoor plans and travel, September usually offers the most comfortable weather in Mason City, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | -4° | -13° | 24 mm | 87% |
| Feb | -1° | -12° | 32 mm | 85% |
| Mar | 7° | -4° | 51 mm | 78% |
| Apr | 15° | 2° | 98 mm | 74% |
| May | 21° | 9° | 124 mm | 75% |
| Jun | 26° | 15° | 146 mm | 77% |
| Jul | 28° | 18° | 106 mm | 76% |
| Aug | 27° | 16° | 102 mm | 75% |
| Sep | 23° | 11° | 98 mm | 73% |
| Oct | 15° | 3° | 73 mm | 74% |
| Nov | 7° | -3° | 42 mm | 79% |
| Dec | -1° | -9° | 41 mm | 87% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Mason City. Values describe typical conditions, not a forecast.
About Mason City weather
Mason City sits within Iowa's humid continental climate, typical of the US corn belt, about 178 km north of Des Moines. Summers bring warm, humid summers (June–August). The year winds down with cold winters (December–February) with regular snow. This page shows live, auto-refreshing weather for Mason City: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
Mason City is about 178 km north of Des Moines, in Iowa.
Mason City sees cold winters (December–February) with regular snow.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Mason City's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Mason City, with average daytime highs of about 28°C and nights around 18°C.
The coldest nights come in January, when the average low is about -13°C and daytime highs reach around -4°C. Frost is possible on clear, calm nights.
Mason City receives about 940 mm of rain in a typical year. June is the wettest month at roughly 146 mm, and the main rainy period is May to August.
September usually offers the most comfortable weather in Mason City, with mild daytime temperatures and little rain.
In November Mason City typically sees daytime highs near 7°C and lows near -3°C, with about 42 mm of rain over the month and average humidity around 79%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
Live temperature for Mason City is shown at the top of this page and refreshes automatically — see the hourly breakdown below for how it changes through the day.
Mason City's day-to-day weather follows the broader pattern of Iowa described above. See the hourly weather forecast or the air quality index for more detail.