Promise City, IA Weather & Growing Conditions
Tonight
46°F
Slight Chance Rain Showers then Cloudy
A slight chance of rain showers before 9pm. Cloudy. Low around 46, with temperatures rising to around 48 overnight. West southwest wind 8 to 13 mph, with gusts as high as 21 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 46°F | Slight Chance Rain Showers then Cloudy | 8 to 13 mph WSW | 15% |
| Wednesday | 54°F | Mostly Cloudy | 10 to 16 mph W | 11% |
| Wednesday Night | 42°F | Mostly Cloudy | 9 mph WSW | 5% |
| Thursday | 53°F | Mostly Cloudy then Chance Rain Showers | 7 to 10 mph WNW | 30% |
| Thursday Night | 40°F | Slight Chance Rain Showers then Mostly Cloudy | 6 mph NNW | 19% |
| Friday | 53°F | Partly Sunny | 3 to 7 mph N | 5% |
| Friday Night | 34°F | Partly Cloudy | 2 mph N | 0% |
| Saturday | 56°F | Partly Sunny | 0 to 3 mph W | 3% |
| Saturday Night | 36°F | Mostly Clear | 3 mph W | 5% |
| Sunday | 61°F | Sunny | 6 mph W | 5% |
| Sunday Night | 38°F | Mostly Clear | 5 mph WSW | 1% |
| Monday | 66°F | Sunny | 5 to 12 mph SW | 0% |
| Monday Night | 41°F | Mostly Clear | 5 mph W | 0% |
| Tuesday | 65°F | Sunny | 5 mph NNW | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Promise City, IA
Last spring frost
Apr 18
First fall frost
Oct 23
Growing season
187 days
Hardiness zone
5b
Explore more for Promise City, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Rathbun Dam, Ia (13.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.