National Weather Service Forecast for: Waterloo IA
Issued by: National Weather Service Des Moines, IA
Updated: 10:43 pm CDT Jun 29, 2026
 
Tonight

Tonight: A 20 percent chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 77. South southwest wind 11 to 15 mph, with gusts as high as 21 mph.
Slight Chance
T-storms

 Tuesday

Tuesday: Mostly sunny, with a high near 94. Heat index values as high as 105. Breezy, with a southwest wind 10 to 16 mph, with gusts as high as 26 mph.
Mostly Sunny
then Mostly
Sunny and
Breezy
 Tuesday
Night
Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly between 2am and 3am. Partly cloudy, with a low around 75. South southwest wind 10 to 13 mph, with gusts as high as 21 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Chance
T-storms

 Wednesday

Wednesday: Mostly sunny, with a high near 93. Heat index values as high as 100. Breezy, with a south southwest wind 9 to 16 mph, with gusts as high as 26 mph.
Mostly Sunny
then Mostly
Sunny and
Breezy
 Wednesday
Night
Wednesday Night: A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Partly cloudy, with a low around 75. Breezy, with a south southwest wind 13 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Slight Chance
T-storms and
Breezy then
Showers
Likely
 Thursday

Thursday: A 30 percent chance of showers and thunderstorms, mainly before 1pm. Mostly sunny, with a high near 91. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Chance
T-storms

 Thursday
Night
Thursday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Partly cloudy, with a low around 73. Chance of precipitation is 60%.
Chance
T-storms then
Showers
Likely
 Friday

Friday: A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
Chance
Showers then
Chance
T-storms
 Friday
Night
Friday Night: A 30 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72.
Mostly Clear
then Chance
T-storms
Lo 77 °F Hi 94 °F Lo 75 °F Hi 93 °F Lo 75 °F Hi 91 °F Lo 73 °F Hi 90 °F Lo 72 °F

Hazardous Weather Outlook
Extreme Heat Warning
 

Tonight
 
 A 20 percent chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 77. South southwest wind 11 to 15 mph, with gusts as high as 21 mph.
Tuesday
 
 Mostly sunny, with a high near 94. Heat index values as high as 105. Breezy, with a southwest wind 10 to 16 mph, with gusts as high as 26 mph.
Tuesday Night
 
 A 30 percent chance of showers and thunderstorms, mainly between 2am and 3am. Partly cloudy, with a low around 75. South southwest wind 10 to 13 mph, with gusts as high as 21 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday
 
 Mostly sunny, with a high near 93. Heat index values as high as 100. Breezy, with a south southwest wind 9 to 16 mph, with gusts as high as 26 mph.
Wednesday Night
 
 A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Partly cloudy, with a low around 75. Breezy, with a south southwest wind 13 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Thursday
 
 A 30 percent chance of showers and thunderstorms, mainly before 1pm. Mostly sunny, with a high near 91. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday Night
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Partly cloudy, with a low around 73. Chance of precipitation is 60%.
Friday
 
 A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
Friday Night
 
 A 30 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72.
Independence Day
 
 A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 89.
Saturday Night
 
 A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.
Sunday
 
 A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 86.
Sunday Night
 
 Partly cloudy, with a low around 66.
Monday
 
 Mostly sunny, with a high near 85.

 

Forecast from NOAA-NWS for Waterloo IA.