Portland is at its most pleasant from late May to early October. For walking, go from mid March to early July. It is rarely warm enough for sunbathing.
When to go five ratings · thirty-six ten-day sections · click a cell to read it
Portland never quite rates Good for sun. It comes closest in early August, at 52, mostly because it is too cool. The weakest stretch is from October to early May, when it drops to 0, mostly because it is too cool. The clearest skies come in July, when the sky is typically 31% covered at midday (mostly clear).
For being outside, go from late May to early October. It peaks in early July, at 90. Avoid mid November to early March for this: it falls to 0, mostly because it is too cold.
The walking season here runs from mid March to early July, with a second spell from late August to early November. It peaks in late April, at 88. The weakest stretch is from December to mid January, when it drops to 19, mostly because it is too cold.
The year, measured
The average temperature in Portland over the whole year is 13°C. August is the hottest month, with highs of about 27°C; February is the coldest, with lows of about 4°C. The rainy (wet) season in Portland runs from October to April, peaking in January with a 25% chance of rain on a given day. The dry season is May to September; July is the driest month, at 3%. Winds in Portland are highest in January, averaging 3.6 m/s (13 km/h), and lightest in September, at 1.8 m/s (6 km/h). The prevailing wind is from the S. The clearest skies in Portland come in July, when the sky is typically 28% covered; February is the cloudiest month, at 73%.
Month by month Portland climate by month: average temperatures year round · click a month to read it
| Month | High | Low | Feels like | Chance of rain | Cloud | Wind | Being outside | Sun | Walking |
|---|---|---|---|---|---|---|---|---|---|
| January | 7°C | 4°C | 2°C | 25% | 72% | 3.6 m/s | 0 | 0 | 23 |
| February | 7°C | 4°C | 3°C | 22% | 73% | 3.0 m/s | 0 | 0 | 29 |
| March | 11°C | 5°C | 7°C | 21% | 65% | 2.7 m/s | 5 | 0 | 52 |
| April | 15°C | 7°C | 11°C | 17% | 58% | 2.5 m/s | 22 | 1 | 76 |
| May | 19°C | 11°C | 16°C | 12% | 53% | 2.2 m/s | 57 | 7 | 84 |
| June | 23°C | 14°C | 19°C | 9% | 47% | 2.2 m/s | 75 | 17 | 74 |
| July | 27°C | 16°C | 23°C | 3% | 28% | 2.2 m/s | 84 | 39 | 54 |
| August | 27°C | 15°C | 24°C | 3% | 31% | 1.9 m/s | 80 | 44 | 47 |
| September | 22°C | 13°C | 20°C | 9% | 46% | 1.8 m/s | 85 | 17 | 74 |
| October | 16°C | 9°C | 13°C | 18% | 55% | 2.1 m/s | 41 | 2 | 83 |
| November | 10°C | 7°C | 7°C | 25% | 69% | 2.8 m/s | 5 | 0 | 51 |
| December | 7°C | 4°C | 3°C | 24% | 72% | 3.3 m/s | 0 | 0 | 22 |
High and low are the warmest and coolest of four readings a day — midnight, 6am, noon and 6pm — so a true overnight low can sit a degree or two under them. Chance of rain, cloud and wind are the day’s average; feels-like and the three ratings (each out of 100: Good from 55, Ideal from 80) are read at midday.
Seasons, and the year in short Portland weather by season
Year round, Portland has days of about 7°C at their warmest in January, its coolest month, and 27°C in August, its warmest; the coolest hours of the day run from 4°C to 16°C through the year, and the average temperature over the year is 13°C around the clock. Rain is most likely around January and least likely around July. Every figure here is a decade of observations blended into one representative year, so it reads as what this date is usually like, not a forecast for one particular day.
Portland weather in winterDecember to February
Winter in Portland has typical daily highs of about 7°C and lows of about 4°C, with a 24% chance of rain on a given day.
Portland weather in springMarch to May
Spring in Portland has typical daily highs of about 15°C and lows of about 8°C, with a 17% chance of rain on a given day.
Portland weather in summerJune to August
Summer in Portland has typical daily highs of about 26°C and lows of about 15°C, with a 5% chance of rain on a given day.
Portland weather in autumnSeptember to November
Autumn in Portland has typical daily highs of about 16°C and lows of about 10°C, with a 17% chance of rain on a given day.
When is the rainy season in Portland?
The rainy (wet) season in Portland runs from October to April, peaking in January with a 25% chance of rain on a given day. The dry season is May to September; July is the driest month, at 3%.
What time of year is Portland windiest?
Winds in Portland are highest in January, averaging 3.6 m/s (13 km/h), and lightest in September, at 1.8 m/s (6 km/h). The prevailing wind is from the S.
What is the average temperature in Portland year round?
The average temperature in Portland over the whole year is 13°C. August is the hottest month, with highs of about 27°C; February is the coldest, with lows of about 4°C.
Where to go instead in early January, the weakest time here for being outside
How this is worked out
Every figure is a decade of weather-station observations blended into one typical year, in ten-day sections. The ratings, the chart and the feels-like column are read at midday local solar time. Being outside is the Easy outdoors rating, Sun is Sunbathing and Walking is Active outdoors, each out of 100: Good from 55, Ideal from 80. They describe what a time of year is usually like here, not a forecast. The dotted links open the map at that time of year; set its time of day to midday to see these numbers.