Harman US

Keystone, IA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Keystone, a city in Benton County, Iowa.

Overnight
66°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 4am, then patchy fog and showers and thunderstorms likely. Cloudy, with a low around 66. Southeast wind 5 to 10 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

7-day forecast for Keystone

WhenTempForecastWindPrecip
Overnight 66°F Chance Showers And Thunderstorms 5 to 10 mph SE 72%
Saturday 80°F Patchy Fog 5 to 10 mph S 77%
Saturday Night 61°F Showers And Thunderstorms Likely 5 to 10 mph N 67%
Sunday 67°F Rain Showers Likely 10 to 15 mph NE 59%
Sunday Night 55°F Chance Rain Showers 10 to 15 mph NE 47%
Monday 63°F Chance Rain Showers 10 to 15 mph NE 47%
Monday Night 50°F Chance Rain Showers 10 mph NE 36%
Tuesday 61°F Chance Rain Showers then Partly Sunny 10 mph NE 27%
Tuesday Night 46°F Mostly Clear 5 mph NE 4%
Wednesday 66°F Sunny 5 mph NE 0%
Wednesday Night 50°F Partly Cloudy 0 to 5 mph NE 3%
Thursday 67°F Partly Sunny 5 mph E 8%
Thursday Night 53°F Partly Cloudy 0 to 5 mph E 6%
Friday 69°F Mostly Sunny 5 mph E 6%

Forecast source: National Weather Service (api.weather.gov) for Keystone (41.999, -92.198). Updated through the day.

Growing snapshot for Keystone

Last spring frost
Apr 28
First fall frost
Oct 10
Growing season
165 days
Hardiness zone
5a

More local growing data for Keystone: nearby ZIP 52249 weather · frost dates · planting calendar · Iowa frost dates

Nearby towns & communities

All Iowa locations ›

Climate data from the nearest NOAA station, Belle Plaine, Ia (9.7 mi from Keystone). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.