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March Weather in Portland, United States

Last updated: June 24, 2025

In March, the average temperature in Portland, United States hovers around 4°C (40°F), with temperatures ranging from a bone-chilling -19°C (-2°F) to a balmy 24°C (76°F). Expect 90 mm (3.6 in) of precipitation over approximately 10 days, accompanied by an average humidity level of 81%. Whether you're dressing for the cold or braving the wet weather, be prepared for a diverse climate this month!

March Temperature in Portland

In March in Portland, the average temperature is 4°C (40°F). Maximums can reach 24°C (76°F) while minimums can drop to as low as -19°C (-2°F). Travelers should be prepared for a wide range of weather conditions, from chilly temperatures to warmer days.

March Weather in Portland: Daily Temperature Highs, Lows, and Averages

The chart illustrates March temperature patterns in Portland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portland, March typically has an average temperature of 4°C (40°F), with highs reaching up to 24°C (76°F) and lows dropping to around -19°C (-2°F).
JanFebMarAprMayJunJulAugSepOctNovDec323439495969757467574436
Data source: Temperature data for Portland generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

March Precipitation in Portland

In Portland in March, the precipitation amount is 90 mm (3.6 in) spread over the course of 10 days.

March Precipitation Trends in Portland

The chart displays monthly precipitation patterns in Portland, with values for each month alongside March’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how March’s conditions compare to those of other months. In Portland, March typically receives around 90 mm (3.6 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec67909012611194156969913090127
Data source: Precipitation data for March generated using information from the Copernicus Climate Change Service.
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March Humidity in Portland

In Portland in March humidity is 81%. With an average temperature of 4°C (40°F), this humidity feels like a damp chill that can make traveling quite uncomfortable, as the cold air clings uncomfortably to your skin and the moisture can quickly sap your body heat.

March Average Humidity in Portland

This chart illustrates the average monthly humidity levels in Portland, with March’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In March, average humidity in Portland is approximately 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for March generated using information from the Copernicus Climate Change Service.

March UV Index in Portland

In Portland in March, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Portland, you can refer to this Hourly UV Index in Portland.

Maximum UV Index Levels in Portland for March

The chart shows the monthly maximum UV Index (UVI) for Portland in March, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In March, the maximum UV index in Portland typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35681010998642
Data source: Portland March UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How March Weather in Portland Compares to Other Months

Weather in Portland varies notably across the year, with each month offering distinct climate conditions. This page compares March’s weather to other months in Portland, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Portland, showing how March’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)67 mm (2.6 inches)84%moderate
February Weather1°C (34°F)89 mm (3.5 inches)82%moderate
March Weather4°C (40°F)90 mm (3.6 inches)81%high
April Weather10°C (49°F)126 mm (5.0 inches)78%very high
May Weather15°C (60°F)111 mm (4.4 inches)69%very high
June Weather20°C (69°F)94 mm (3.7 inches)69%very high
July Weather24°C (75°F)156 mm (6.1 inches)62%very high
August Weather23°C (74°F)96 mm (3.8 inches)65%very high
September Weather20°C (67°F)99 mm (3.9 inches)68%very high
October Weather14°C (58°F)130 mm (5.1 inches)74%high
November Weather7°C (44°F)90 mm (3.6 inches)82%moderate
December Weather2°C (36°F)127 mm (5.0 inches)80%low

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