Portland, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Portland, a community in Cerro Gordo County, Iowa.
Overnight
45°F
Chance Rain Showers
A chance of rain showers. Cloudy. Low around 45, with temperatures rising to around 48 overnight. West northwest wind around 10 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Portland
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 45°F | Chance Rain Showers | 10 mph WNW | 51% |
| Wednesday | 51°F | Chance Rain Showers | 12 to 15 mph W | 51% |
| Wednesday Night | 42°F | Rain Showers Likely | 9 to 13 mph WNW | 66% |
| Thursday | 50°F | Chance Rain Showers then Cloudy | 10 to 14 mph NNW | 43% |
| Thursday Night | 33°F | Mostly Cloudy | 5 to 9 mph N | 5% |
| Friday | 47°F | Mostly Sunny | 2 to 6 mph NNE | 1% |
| Friday Night | 26°F | Partly Cloudy | 1 mph N | 0% |
| Saturday | 50°F | Mostly Sunny | 0 to 5 mph SW | 0% |
| Saturday Night | 33°F | Mostly Clear | 5 mph W | 2% |
| Sunday | 56°F | Sunny | 3 to 7 mph W | 2% |
| Sunday Night | 34°F | Mostly Clear | 3 mph SW | 0% |
| Monday | 62°F | Sunny | 3 to 9 mph SW | 0% |
| Monday Night | 37°F | Mostly Clear | 5 mph WNW | 0% |
| Tuesday | 59°F | Mostly Sunny | 3 mph NW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Portland (43.123, -93.137). Updated through the day.
Growing snapshot for Portland
Last spring frost
Apr 29
First fall frost
Oct 7
Growing season
161 days
Hardiness zone
5a
More local growing data for Portland: nearby ZIP 50401 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mason City, Ia (0.7 mi from Portland). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.