Mercer, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mercer, a community in Iron County, Wisconsin.
Tonight
46°F
Cloudy then Slight Chance Drizzle
A slight chance of drizzle after 1am. Cloudy, with a low around 46. Southeast wind around 5 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Mercer
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 46°F | Cloudy then Slight Chance Drizzle | 5 mph SE | 17% |
| Saturday | 64°F | Slight Chance Drizzle then Patchy Fog | 5 mph E | 17% |
| Saturday Night | 44°F | Mostly Cloudy | 0 to 5 mph NE | 9% |
| Sunday | 63°F | Mostly Cloudy | 5 to 10 mph NE | 0% |
| Sunday Night | 35°F | Mostly Cloudy | 5 to 10 mph NE | 0% |
| Monday | 63°F | Partly Sunny | 5 mph E | 0% |
| Monday Night | 36°F | Partly Cloudy | 0 to 5 mph E | 0% |
| Tuesday | 65°F | Mostly Sunny | 0 to 5 mph E | 1% |
| Tuesday Night | 36°F | Mostly Clear | 0 to 5 mph E | 2% |
| Wednesday | 67°F | Sunny | 0 to 5 mph SE | 2% |
| Wednesday Night | 40°F | Partly Cloudy | 0 to 5 mph SE | 1% |
| Thursday | 70°F | Mostly Sunny | 0 to 5 mph SW | 5% |
| Thursday Night | 42°F | Partly Cloudy | 0 to 5 mph SW | 6% |
| Friday | 72°F | Mostly Sunny | 0 to 5 mph NW | 3% |
Forecast source: National Weather Service (api.weather.gov) for Mercer (46.161, -90.042). Updated through the day.
Growing snapshot for Mercer
Last spring frost
May 25
First fall frost
Sep 21
Growing season
117 days
Hardiness zone
4a
More local growing data for Mercer: nearby ZIP 54547 weather · frost dates · planting calendar · Wisconsin frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Rest Lake, Wi (12.6 mi from Mercer). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.