| National Weather Service Forecast for:
Johnston IA Issued by: National Weather Service Des Moines, IA |
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| Updated: 5:47 pm CDT Jul 16, 2026 | ||||||||||||||||||
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| Tonight |
Partly cloudy, with a low around 72. Light south wind. |
| Friday |
Mostly sunny, with a high near 93. Heat index values as high as 102. Calm wind becoming southwest 5 to 8 mph in the afternoon. |
| Friday Night |
Mostly clear, with a low around 74. Southwest wind 3 to 6 mph. |
| Saturday |
Sunny, with a high near 93. Heat index values as high as 101. West wind 5 to 7 mph becoming north northwest in the afternoon. |
| Saturday Night |
Mostly clear, with a low around 69. North northeast wind 5 to 7 mph becoming calm in the evening. |
| Sunday |
Sunny, with a high near 91. |
| Sunday Night |
Partly cloudy, with a low around 73. |
| Monday |
A 20 percent chance of showers and thunderstorms. Mostly sunny and hot, with a high near 97. |
| Monday Night |
Partly cloudy, with a low around 72. |
| Tuesday |
Sunny, with a high near 88. |
| Tuesday Night |
Partly cloudy, with a low around 64. |
| Wednesday |
Mostly sunny, with a high near 82. |
| Wednesday Night |
Partly cloudy, with a low around 63. |
| Thursday |
Mostly sunny, with a high near 80. |
Forecast from NOAA-NWS for Johnston IA.
