Johnston, IA Weather & Climate Normals
What a normal year in Johnston actually looks like
On the 30-year record NOAA keeps for Johnston, IA, the comfort score comes out to 37/100, weather-driven: Heat, cold, snow, or rainfall here are heavy enough that they shape daily life for a large part of the year. Only 4 months a year land in the 55–75°F range this site treats as mild.
How much Johnston's weather actually swings
Average temperatures in Johnston run from 22°F in Jan up to 75°F in Jul, a 53.6°F seasonal swing, one of the widest gaps in this dataset.
Johnston, month by month
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 30°F | 13°F | 1.01in | 9.7in |
| Feb | 35°F | 17°F | 1.25in | 10.5in |
| Mar | 49°F | 29°F | 2.15in | 5in |
| Apr | 62°F | 40°F | 4in | 1.6in |
| May | 72°F | 52°F | 4.84in | 0.2in |
| Jun | 81°F | 62°F | 5.35in | 0in |
| Jul | 85°F | 66°F | 4.27in | 0in |
| Aug | 83°F | 64°F | 3.97in | 0in |
| Sep | 76°F | 55°F | 3.4in | 0in |
| Oct | 63°F | 43°F | 2.51in | 0.5in |
| Nov | 48°F | 30°F | 1.95in | 2.2in |
| Dec | 35°F | 19°F | 1.46in | 8.3in |
If you're timing a visit, May, Jun, Aug, and Sep are Johnston's mildest stretch; if you're moving there, you should plan around Jul's heat and Jan's cold instead.
How wet Johnston actually gets
Over a typical year, Johnston sees about 36.16in of precipitation a year across roughly 112 days with measurable rain or snow, with 38in of snow a year.
Johnston against the rest of the country
Out of 4876 cities scored here, Johnston comes in at 4756; within IA alone it ranks 80 of 85. Population is about 25,022.
Checking the actual forecast
These figures come from Des Moines Wsfo-Johnston, IA US, the NOAA station 3.1 miles from Johnston, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why this uses the nearest NOAA station · How the comfort score is calculated