National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Hazardous Weather Conditions

Current conditions at

Madison, Dane County Regional-Truax Field (KMSN)

Lat: 43.14°NLon: 89.35°WElev: 860ft.

Overcast

64°F

18°C

Humidity 87%
Wind Speed SE 13 mph
Barometer 30.22 in (1023.2 mb)
Dewpoint 60°F (16°C)
Visibility 10.00 mi
Last update 18 Sep 12:53 pm CDT
Extended Forecast for

Sun Prairie WI

Flood Watch September 19, 01:00am until September 19, 01:00pm
Click here for hazard details and duration
Flood Watch

  • This Afternoon

    This Afternoon: Showers likely, mainly before 2pm. Mostly cloudy, with a high near 69. East wind 10 to 15 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    High: 69 °F

    Showers
    Likely

  • Tonight

    Tonight: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after midnight. Some of the storms could produce heavy rainfall. Low around 59. East wind 10 to 15 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

    Low: 59 °F

    Chance
    Showers then
    Heavy Rain

  • Saturday

    Saturday: Showers and possibly a thunderstorm before 1pm, then a chance of showers and thunderstorms between 1pm and 3pm, then showers likely and possibly a thunderstorm after 3pm. High near 72. Southeast wind around 10 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.

    High: 72 °F

    Showers

  • Saturday Night

    Saturday Night: Showers and possibly a thunderstorm before 10pm, then showers likely. Low around 58. Northeast wind around 10 mph. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.

    Low: 58 °F

    Showers

  • Sunday

    Sunday: A 30 percent chance of showers, mainly before 1pm. Mostly cloudy, with a high near 67. Northeast wind around 15 mph.

    High: 67 °F

    Chance
    Showers

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 52. Northeast wind around 15 mph.

    Low: 52 °F

    Mostly Cloudy

  • Monday

    Monday: A 30 percent chance of showers after 1pm. Mostly cloudy, with a high near 63. East wind around 15 mph.

    High: 63 °F

    Mostly Cloudy
    then Chance
    Showers

  • Monday Night

    Monday Night: A 20 percent chance of showers. Mostly cloudy, with a low around 48. Northeast wind around 10 mph.

    Low: 48 °F

    Slight Chance
    Showers

  • Tuesday

    Tuesday: Partly sunny, with a high near 62.

    High: 62 °F

    Partly Sunny

Detailed Forecast

This Afternoon
Showers likely, mainly before 2pm. Mostly cloudy, with a high near 69. East wind 10 to 15 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Tonight
A chance of showers and thunderstorms, then showers and possibly a thunderstorm after midnight. Some of the storms could produce heavy rainfall. Low around 59. East wind 10 to 15 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Saturday
Showers and possibly a thunderstorm before 1pm, then a chance of showers and thunderstorms between 1pm and 3pm, then showers likely and possibly a thunderstorm after 3pm. High near 72. Southeast wind around 10 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Saturday Night
Showers and possibly a thunderstorm before 10pm, then showers likely. Low around 58. Northeast wind around 10 mph. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.
Sunday
A 30 percent chance of showers, mainly before 1pm. Mostly cloudy, with a high near 67. Northeast wind around 15 mph.
Sunday Night
Mostly cloudy, with a low around 52. Northeast wind around 15 mph.
Monday
A 30 percent chance of showers after 1pm. Mostly cloudy, with a high near 63. East wind around 15 mph.
Monday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 48. Northeast wind around 10 mph.
Tuesday
Partly sunny, with a high near 62.
Tuesday Night
Partly cloudy, with a low around 46.
Wednesday
Mostly sunny, with a high near 65.
Wednesday Night
Partly cloudy, with a low around 48.
Thursday
Partly sunny, with a high near 68.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Sun Prairie WI
 43.17°N 89.21°W (Elev. 948 ft)
Last Update:
1:35 pm CDT Sep 18, 2026
Forecast Valid:
1pm CDT Sep 18, 2026-6pm CDT Sep 24, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation