National Weather Service Forecast for: Waukesha WI
Issued by: National Weather Service Milwaukee, WI
Updated: 3:01 am CDT Jun 30, 2026
 
Overnight

Overnight: Partly cloudy, with a low around 76. Southwest wind around 5 mph.
Partly Cloudy

 Tuesday

Tuesday: Mostly sunny and hot, with a high near 94. Heat index values as high as 106. Southwest wind 10 to 15 mph, with gusts as high as 25 mph.
Hot

 Tuesday
Night
Tuesday Night: Mostly clear, with a low around 75. Southwest wind 10 to 15 mph.
Mostly Clear

 Wednesday

Wednesday: Sunny and hot, with a high near 94. Heat index values as high as 102. Southwest wind 5 to 15 mph.
Hot

 Wednesday
Night
Wednesday Night: A slight chance of showers between 1am and 4am, then a slight chance of showers and thunderstorms after 4am. Mostly clear, with a low around 75. Southwest wind around 10 mph. Chance of precipitation is 20%.
Mostly Clear
then Slight
Chance
T-storms
 Thursday

Thursday: A slight chance of thunderstorms before 7am, then a chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 92. Southwest wind around 10 mph. Chance of precipitation is 40%.
Mostly Sunny
then Chance
T-storms
 Thursday
Night
Thursday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 71. West wind around 5 mph becoming calm after midnight. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Chance
T-storms then
Showers
Likely
 Friday

Friday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 88. Light southwest wind increasing to 5 to 10 mph in the morning. 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 67. Chance of precipitation is 60%.
Showers
Likely
Lo 76 °F Hi 94 °F Lo 75 °F Hi 94 °F Lo 75 °F Hi 92 °F Lo 71 °F Hi 88 °F Lo 67 °F

Hazardous Weather Outlook
Extreme Heat Warning
 

Overnight
 
 Partly cloudy, with a low around 76. Southwest wind around 5 mph.
Tuesday
 
 Mostly sunny and hot, with a high near 94. Heat index values as high as 106. Southwest wind 10 to 15 mph, with gusts as high as 25 mph.
Tuesday Night
 
 Mostly clear, with a low around 75. Southwest wind 10 to 15 mph.
Wednesday
 
 Sunny and hot, with a high near 94. Heat index values as high as 102. Southwest wind 5 to 15 mph.
Wednesday Night
 
 A slight chance of showers between 1am and 4am, then a slight chance of showers and thunderstorms after 4am. Mostly clear, with a low around 75. Southwest wind around 10 mph. Chance of precipitation is 20%.
Thursday
 
 A slight chance of thunderstorms before 7am, then a chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 92. Southwest wind around 10 mph. Chance of precipitation is 40%.
Thursday Night
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 71. West wind around 5 mph becoming calm after midnight. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 88. Light southwest wind increasing to 5 to 10 mph in the morning. 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 67. Chance of precipitation is 60%.
Independence Day
 
 A 50 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 84.
Saturday Night
 
 A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 65.
Sunday
 
 A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
Sunday Night
 
 A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 63.
Monday
 
 A 20 percent chance of showers. Mostly sunny, with a high near 84.

 

Forecast from NOAA-NWS for Waukesha WI.