Climate Insights for Portland International Jetport

The climate in Portland International Jetport is cool. The average annual temperature is 9°C and approximately 1156mm of precipitation falls per year. Portland International Jetport receives a notable amount of rainfall throughout the year, including during its driest month. Portland International Jetport is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are January, February, December, when temperatures can drop to -7°C. Portland International Jetport experiences heavy snowfall, typically from January through December.

Temperatures in Portland International Jetport vary considerably across the year, with a 33°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 26°C and the mean temperature sits around 22°C. The coldest month is January, when overnight lows fall to -7°C and the daily average is -4°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows. The sharpest temperature change occurs between October and November, with a 7°C shift in average temperatures.

Portland International Jetport is a moderately rainy area, receiving approximately 1156mm of precipitation annually, which averages out to around 96mm per month. The wettest month is October, averaging 137mm of rainfall. December and April also tend to see above-average precipitation. The driest month is September, with just 49mm. That's 87mm less than October, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall. Portland International Jetport receives heavy snowfall, accumulating around 236cm annually from January through December. The snowiest month is December, with approximately 56cm. Winter travel should account for significant snow cover.

Portland International Jetport is relatively calm, with an average annual wind speed of 3km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is March, averaging 4km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 1km/h between the calmest and windiest months.

It is currently spring in Portland International Jetport, which began on March 20, 2026. Portland International Jetport is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 26°C, while the coldest stretch bottoms out in January near -7°C. Summer is next, beginning on June 21, 2026 — 4 days from now.

The best time to visit Portland International Jetport is during June, July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 74mm per month. By contrast, January can be quite cold with temperatures dropping to -7°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Portland International Jetport based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.