Portland, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Portland, a community in Cerro Gordo County, Iowa.
Overnight
63°F
Patchy Fog
Patchy fog and a chance of showers and thunderstorms. Cloudy, with a low around 63. East southeast wind around 9 mph. Chance of precipitation is 50%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Portland
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 63°F | Patchy Fog | 9 mph ESE | 50% |
| Saturday | 72°F | Patchy Fog | 6 to 9 mph N | 52% |
| Saturday Night | 56°F | Slight Chance Showers And Thunderstorms | 10 mph NNE | 22% |
| Sunday | 66°F | Mostly Cloudy | 14 mph NE | 10% |
| Sunday Night | 50°F | Mostly Cloudy then Chance Rain Showers | 12 mph ENE | 25% |
| Monday | 61°F | Chance Rain Showers | 12 mph ENE | 39% |
| Monday Night | 45°F | Chance Rain Showers | 5 to 8 mph ENE | 30% |
| Tuesday | 61°F | Mostly Sunny | 5 to 8 mph ENE | 12% |
| Tuesday Night | 42°F | Partly Cloudy | 5 mph E | 1% |
| Wednesday | 64°F | Sunny | 5 mph E | 1% |
| Wednesday Night | 46°F | Partly Cloudy | 3 mph ESE | 6% |
| Thursday | 65°F | Partly Sunny | 1 to 5 mph SE | 10% |
| Thursday Night | 50°F | Partly Cloudy | 2 mph ESE | 4% |
| Friday | 68°F | Mostly Sunny | 1 to 6 mph ESE | 4% |
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 Sep 19, 2026.