Portland, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Portland, a community in Cerro Gordo County, Iowa.
Overnight
65°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Mostly cloudy, with a low around 65. South southwest wind around 8 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Portland
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 65°F | Chance Showers And Thunderstorms | 8 mph SSW | 28% |
| Tuesday | 73°F | Showers And Thunderstorms Likely | 9 mph NW | 66% |
| Tuesday Night | 56°F | Chance Showers And Thunderstorms | 2 to 7 mph NNW | 48% |
| Wednesday | 73°F | Mostly Sunny | 3 mph NNE | 3% |
| Wednesday Night | 53°F | Mostly Clear | 1 mph NW | 2% |
| Thursday | 78°F | Sunny | 0 to 5 mph S | 1% |
| Thursday Night | 59°F | Mostly Clear | 5 mph S | 1% |
| Friday | 81°F | Sunny | 3 to 12 mph S | 8% |
| Friday Night | 64°F | Slight Chance Showers And Thunderstorms | 6 to 9 mph S | 18% |
| Saturday | 84°F | Slight Chance Showers And Thunderstorms then Sunny | 5 to 9 mph S | 15% |
| Saturday Night | 68°F | Chance Showers And Thunderstorms | 8 to 12 mph SSW | 34% |
| Sunday | 85°F | Chance Showers And Thunderstorms | 9 mph SSE | 34% |
| Sunday Night | 67°F | Slight Chance Showers And Thunderstorms | 8 mph SSE | 33% |
| Monday | 83°F | Chance Showers And Thunderstorms | 10 mph ESE | 33% |
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 Aug 4, 2026.