Castalia, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Castalia, a city in Winneshiek County, Iowa.
Today
70°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy. High near 70, with temperatures falling to around 68 in the afternoon. Southwest wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.
7-day forecast for Castalia
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 70°F | Showers And Thunderstorms | 5 mph SW | 79% |
| Tonight | 57°F | Showers And Thunderstorms Likely | 6 to 10 mph N | 65% |
| Sunday | 64°F | Chance Rain Showers | 13 mph NE | 25% |
| Sunday Night | 51°F | Mostly Cloudy then Slight Chance Rain Showers | 12 mph NE | 18% |
| Monday | 61°F | Chance Rain Showers | 12 mph NE | 25% |
| Monday Night | 46°F | Slight Chance Rain Showers then Mostly Cloudy | 6 to 9 mph NE | 21% |
| Tuesday | 60°F | Mostly Sunny | 8 mph NE | 14% |
| Tuesday Night | 42°F | Mostly Clear | 5 mph NE | 2% |
| Wednesday | 64°F | Sunny | 5 mph E | 1% |
| Wednesday Night | 47°F | Partly Cloudy | 2 mph E | 3% |
| Thursday | 65°F | Mostly Sunny | 3 mph E | 9% |
| Thursday Night | 50°F | Partly Cloudy | 1 mph E | 3% |
| Friday | 68°F | Mostly Sunny | 3 mph E | 5% |
| Friday Night | 51°F | Partly Cloudy | 2 mph E | 5% |
Forecast source: National Weather Service (api.weather.gov) for Castalia (43.113, -91.677). Updated through the day.
Growing snapshot for Castalia
Last spring frost
May 1
First fall frost
Oct 3
Growing season
153 days
Hardiness zone
5a
More local growing data for Castalia: nearby ZIP 52133 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Postville, Ia (5.3 mi from Castalia). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.