Williamson, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamson, a city in Lucas County, Iowa.
This Afternoon
85°F
Slight Chance Showers And Thunderstorms
A slight chance of rain showers before 4pm, then a slight chance of showers and thunderstorms between 4pm and 5pm. Partly sunny, with a high near 85. Southwest wind around 10 mph, with gusts as high as 18 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Williamson
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 85°F | Slight Chance Showers And Thunderstorms | 10 mph SW | 19% |
| Tonight | 63°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 6 mph NNW | 79% |
| Sunday | 66°F | Chance Showers And Thunderstorms then Chance Drizzle | 7 to 12 mph NNE | 50% |
| Sunday Night | 57°F | Showers And Thunderstorms Likely | 10 mph NE | 63% |
| Monday | 59°F | Rain Showers | 10 mph NE | 81% |
| Monday Night | 53°F | Rain Showers | 9 mph NNE | 79% |
| Tuesday | 58°F | Slight Chance Rain Showers | 8 mph NE | 15% |
| Tuesday Night | 47°F | Partly Cloudy | 3 to 7 mph NE | 3% |
| Wednesday | 61°F | Mostly Sunny | 5 mph NE | 0% |
| Wednesday Night | 51°F | Partly Cloudy | 3 mph E | 2% |
| Thursday | 65°F | Slight Chance Rain Showers | 3 mph SE | 17% |
| Thursday Night | 57°F | Chance Rain Showers | 2 mph ESE | 25% |
| Friday | 68°F | Chance Rain Showers | 1 to 5 mph E | 25% |
| Friday Night | 58°F | Mostly Cloudy | 3 mph E | 8% |
Forecast source: National Weather Service (api.weather.gov) for Williamson (41.088, -93.257). Updated through the day.
Growing snapshot for Williamson
Last spring frost
May 5
First fall frost
Oct 5
Growing season
151 days
Hardiness zone
5b
More local growing data for Williamson: nearby ZIP 50272 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Chariton 1 E, Ia (5.1 mi from Williamson). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.