Portland Climate & Weather Averages
United States · Oceanic climate · Data averaged from 2020-01-01 to 2024-12-31 (5 years)
Best Time to Visit Portland
Based on temperature comfort, low rainfall, and sunshine hours, the best months to visit Portland are:
July, August, June
Scores based on ideal temperature (18-28°C), low precipitation, and high sunshine. July scores 90/100.
Portland has a Oceanic climate with mild summers and cold winters. The warmest month is August with an average temperature of 21.5°C (70.7°F), while February is the coldest at 4.8°C (40.6°F). Annual precipitation averages 1435.0mm spread across approximately 183.0 rainy days per year, with December being the wettest month at 247.2mm and July the driest at 5.1mm. The city receives an average of 3.5-13.5 hours of sunshine per day, with the sunniest months being July and August. Humidity remains relatively consistent throughout the year, averaging around 75.0% annually, while average wind speeds reach 17.3 km/h. The overall annual mean temperature is 11.9°C (53.4°F), reflecting the oceanic conditions shaped by Portland's latitude (45.52°) and surrounding geography. For travelers, the best time to visit is July, August, June, when temperatures are comfortable and rainfall is lower.
Portland's climate is similar to Seattle but with slightly warmer summers and cooler winters. I visited during the famous rose festival in June and found the weather ideal. The data shows that the best time to visit is June to September, when the rainfall is minimal and the city's famous outdoor culture thrives. The winter months are grey and wet but the city's coffee shop culture makes it cozy.
Seasonal Climate Overview
Spring (Mar-May)
Average temperature 9.8°C (49.6°F), rainfall 109.4mm, sunshine 8.7 hrs/day, humidity 76.8%. Mild transitional weather characterizes this period. Expect around 18.0 rainy days per month.
Summer (Jun-Aug)
Average temperature 20.0°C (68.0°F), rainfall 32.0mm, sunshine 12.4 hrs/day, humidity 61.9%. Mild transitional weather characterizes this period. Expect around 7.0 rainy days per month.
Autumn (Sep-Nov)
Average temperature 12.7°C (54.9°F), rainfall 132.6mm, sunshine 7.3 hrs/day, humidity 76.5%. Mild transitional weather characterizes this period. Expect around 14.6 rainy days per month.
Winter (Dec-Feb)
Average temperature 5.0°C (41.0°F), rainfall 204.3mm, sunshine 4.2 hrs/day, humidity 84.8%. Cold season conditions dominate. Expect around 21.5 rainy days per month.
Monthly Temperature Averages (°C / °F)
| Month | Avg High | Avg Low | Mean Temp |
|---|---|---|---|
| January | 8.2°C (46.8°F) | 2.4°C (36.3°F) | 5.1°C (41.2°F) |
| February | 8.7°C (47.7°F) | 1.6°C (34.9°F) | 4.8°C (40.6°F) |
| March | 11.5°C (52.7°F) | 2.6°C (36.7°F) | 6.6°C (43.9°F) |
| April | 14.7°C (58.5°F) | 4.6°C (40.3°F) | 9.4°C (48.9°F) |
| May | 18.9°C (66.0°F) | 8.4°C (47.1°F) | 13.3°C (55.9°F) |
| June | 23.3°C (73.9°F) | 11.6°C (52.9°F) | 17.1°C (62.8°F) |
| July | 29.2°C (84.6°F) | 14.8°C (58.6°F) | 21.3°C (70.3°F) |
| August | 29.2°C (84.6°F) | 15.3°C (59.5°F) | 21.5°C (70.7°F) |
| September | 25.1°C (77.2°F) | 12.9°C (55.2°F) | 18.3°C (64.9°F) |
| October | 17.7°C (63.9°F) | 8.7°C (47.7°F) | 12.7°C (54.9°F) |
| November | 10.5°C (50.9°F) | 4.3°C (39.7°F) | 7.1°C (44.8°F) |
| December | 7.9°C (46.2°F) | 2.6°C (36.7°F) | 5.1°C (41.2°F) |
Monthly Precipitation (mm)
| Month | Avg Rainfall | Bar |
|---|---|---|
| January | 238.0 mm | |
| February | 127.7 mm | |
| March | 121.4 mm | |
| April | 109.2 mm | |
| May | 97.6 mm | |
| June | 77.6 mm | |
| July | 5.1 mm | |
| August | 13.2 mm | |
| September | 65.2 mm | |
| October | 111.8 mm | |
| November | 220.8 mm | |
| December | 247.2 mm |
Monthly Rainy Days (avg days with rain > 0.1mm)
| Month | Avg Rainy Days | Bar |
|---|---|---|
| January | 23.0 | |
| February | 19.2 | |
| March | 18.8 | |
| April | 18.2 | |
| May | 17.0 | |
| June | 12.2 | |
| July | 4.0 | |
| August | 4.8 | |
| September | 9.4 | |
| October | 14.4 | |
| November | 20.0 | |
| December | 22.2 |
Monthly Humidity (%)
| Month | Avg Humidity | Bar |
|---|---|---|
| January | 85.8% | |
| February | 82.7% | |
| March | 81.2% | |
| April | 75.5% | |
| May | 73.8% | |
| June | 68.6% | |
| July | 58.2% | |
| August | 58.9% | |
| September | 66.4% | |
| October | 78.7% | |
| November | 84.4% | |
| December | 85.9% |
Monthly Wind Speed (avg max km/h)
| Month | Avg Max Wind | Bar |
|---|---|---|
| January | 21.1 km/h | |
| February | 18.4 km/h | |
| March | 16.4 km/h | |
| April | 16.7 km/h | |
| May | 16.0 km/h | |
| June | 16.2 km/h | |
| July | 16.4 km/h | |
| August | 15.9 km/h | |
| September | 15.3 km/h | |
| October | 15.6 km/h | |
| November | 19.1 km/h | |
| December | 20.7 km/h |
Monthly UV Index (avg max)
| Month | UV Index | Risk Level | Bar |
|---|---|---|---|
| January | — | — | |
| February | — | — | |
| March | — | — | |
| April | — | — | |
| May | — | — | |
| June | — | — | |
| July | — | — | |
| August | — | — | |
| September | — | — | |
| October | — | — | |
| November | — | — | |
| December | — | — |
Monthly Snowfall (cm)
| Month | Avg Snowfall | Bar |
|---|---|---|
| January | 5.5 cm | |
| February | 16.6 cm | |
| March | 6.8 cm | |
| April | 7.4 cm | |
| May | 0.0 cm | |
| June | 0.0 cm | |
| July | 0.0 cm | |
| August | 0.0 cm | |
| September | 0.0 cm | |
| October | 0.0 cm | |
| November | 1.5 cm | |
| December | 7.2 cm |
Monthly Sunshine Hours (daily average)
| Month | Avg Daily Sunshine | Bar |
|---|---|---|
| January | 3.6 hrs | |
| February | 5.4 hrs | |
| March | 7.1 hrs | |
| April | 8.9 hrs | |
| May | 10.1 hrs | |
| June | 11.7 hrs | |
| July | 13.5 hrs | |
| August | 11.9 hrs | |
| September | 10.0 hrs | |
| October | 7.0 hrs | |
| November | 4.8 hrs | |
| December | 3.5 hrs |
Frequently Asked Questions
What is the hottest month in Portland?
August is the hottest month with an average temperature of 21.5°C (70.7°F).
What is the coldest month in Portland?
February is the coldest month with an average temperature of 4.8°C (40.6°F).
What is the rainiest month in Portland?
December is the wettest month with an average of 247.2mm of precipitation. The city experiences about 183.0 rainy days per year.
When is the best time to visit Portland?
The best time to visit Portland is during July, August, June, when temperatures are comfortable and rainfall is lower.
Cities with Similar Climate (Oceanic)
Other Cities in United States
Data Source: Open-Meteo historical archive (2020-01-01 to 2024-12-31). Daily measurements aggregated into monthly climate normals. Coordinates: 45.52°, -122.68°. Timezone: America/Los_Angeles. Last updated: 2026-07-30.