Castalia, IA
Climate overview — based on NOAA 1991-2020 normals from POSTVILLE, IA US.
Year-round temperatures (°F)
Climate summary
Castalia has an annual average temperature of 46°F with about 38.9 inches of precipitation per year and 39.8 inches of snow. The warmest month is July (average high 82.8°F), and the coldest is January (average low 7.4°F). June is typically the wettest month (5.88 in) and January the driest (1.12 in). Snow typically falls from November through April.
Best time to visit Castalia
Full guide →Climate change signal
All-time records →90 of 366 (24.6%) of Castalia's all-time daily heat records have been set since 2015. If records were spread evenly across the station's history, only about 5% would fall in any given decade.
| 1890s | 0 | |
| 1900s | 31 | |
| 1910s | 25 | |
| 1920s | 24 | |
| 1930s | 86 | |
| 1940s | 12 | |
| 1980s | 13 | |
| 1990s | 7 | |
| 2000s | 41 | |
| 2010s | 58 | |
| 2020s | 69 |
Bars: number of all-time daily heat records still standing that were set in each decade.
Monthly averages
| Month | Avg High | Avg Low | Avg Temp | Precipitation | Snow | Rainy days |
|---|---|---|---|---|---|---|
| January | 25.7°F | 7.4°F | 16.6°F | 1.12 in | 12.0 in | 6 |
| February | 29.9°F | 10.5°F | 20.2°F | 1.21 in | 10.4 in | 5 |
| March | 43.0°F | 22.4°F | 32.7°F | 2.09 in | 5.0 in | 7 |
| April | 57.5°F | 34.0°F | 45.8°F | 4.14 in | 1.6 in | 10 |
| May | 69.4°F | 46.9°F | 58.2°F | 4.99 in | — | 12 |
| June | 79.0°F | 57.8°F | 68.4°F | 5.88 in | — | 11 |
| July | 82.8°F | 60.9°F | 71.9°F | 4.52 in | — | 9 |
| August | 80.8°F | 58.2°F | 69.5°F | 4.36 in | — | 9 |
| September | 74.0°F | 49.2°F | 61.6°F | 3.96 in | — | 9 |
| October | 60.6°F | 37.0°F | 48.8°F | 3.00 in | 0.1 in | 8 |
| November | 44.7°F | 25.5°F | 35.1°F | 2.10 in | 2.7 in | 6 |
| December | 31.4°F | 14.0°F | 22.7°F | 1.57 in | 8.0 in | 6 |
Climate twins of Castalia
Why these? →The most climatically similar US cities at least 140 miles away (by monthly temperature + precipitation pattern).