National Weather Service Forecast for: Sun Prairie WI
Issued by: National Weather Service Milwaukee, WI
Updated: 12:32 am CDT Jun 30, 2026
 
Overnight

Overnight: Partly cloudy, with a low around 76. South wind around 10 mph.
Partly Cloudy

 Tuesday

Tuesday: Mostly sunny and hot, with a high near 92. Heat index values as high as 103. Southwest wind 10 to 15 mph, with gusts as high as 25 mph.
Hot

 Tuesday
Night
Tuesday Night: A 20 percent chance of showers and thunderstorms after 2am. Partly cloudy, with a low around 74. Southwest wind around 10 mph.
Partly Cloudy
then Slight
Chance
T-storms
 Wednesday

Wednesday: Sunny and hot, with a high near 92. Heat index values as high as 101. Southwest wind 10 to 15 mph.
Hot

 Wednesday
Night
Wednesday Night: A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74. Southwest wind 10 to 15 mph.
Chance
T-storms

 Thursday

Thursday: A chance of thunderstorms before 7am, then a chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. Southwest wind around 10 mph. Chance of precipitation is 40%.
Chance
T-storms

 Thursday
Night
Thursday Night: Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 71. Southwest wind around 5 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Showers
Likely

 Friday

Friday: Showers likely and possibly a thunderstorm. Partly sunny, with a high near 87. Southwest wind 5 to 10 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Showers
Likely

 Friday
Night
Friday Night: Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 68. Chance of precipitation is 60%.
Showers
Likely
Lo 76 °F Hi 92 °F Lo 74 °F Hi 92 °F Lo 74 °F Hi 89 °F Lo 71 °F Hi 87 °F Lo 68 °F

Hazardous Weather Outlook
Extreme Heat Warning
 

Overnight
 
 Partly cloudy, with a low around 76. South wind around 10 mph.
Tuesday
 
 Mostly sunny and hot, with a high near 92. Heat index values as high as 103. Southwest wind 10 to 15 mph, with gusts as high as 25 mph.
Tuesday Night
 
 A 20 percent chance of showers and thunderstorms after 2am. Partly cloudy, with a low around 74. Southwest wind around 10 mph.
Wednesday
 
 Sunny and hot, with a high near 92. Heat index values as high as 101. Southwest wind 10 to 15 mph.
Wednesday Night
 
 A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74. Southwest wind 10 to 15 mph.
Thursday
 
 A chance of thunderstorms before 7am, then a chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. Southwest wind around 10 mph. Chance of precipitation is 40%.
Thursday Night
 
 Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 71. Southwest wind around 5 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday
 
 Showers likely and possibly a thunderstorm. Partly sunny, with a high near 87. Southwest wind 5 to 10 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday Night
 
 Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 68. Chance of precipitation is 60%.
Independence Day
 
 A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
Saturday Night
 
 A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 66.
Sunday
 
 A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 84.
Sunday Night
 
 A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 64.
Monday
 
 A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 83.

 

Forecast from NOAA-NWS for Sun Prairie WI.