Portland climate

Portland Weather in May

NOAA 1991-2020 normals for Portland 1 Sw, 2.3 km from Portland

Average highs run from 67°F on May 1 to 76°F on May 31, and lows from 44°F to 55°F. Normal precipitation for the month is 4.31 in over about 12 wet days.

May day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Portland, in °F, with the record for each date.20406080100151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

May at a glance

Average high
72°F
Average low
49°F
Precipitation
4.31 in
Record high
92°FMay 28, 2012
Record low
26°FMay 8, 2020
Chance of a freeze
41%
Daylight
13 h 57 min to 14 h 51 min
Cloud cover
65%
Humidity
77%
Dew point
53°F
Wind
10.3 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
May 167°F44°F83°F 200127°F 197938%0%
May 268°F44°F83°F 199231°F 199438%0%
May 368°F44°F84°F 202430°F 197838%0%
May 468°F45°F86°F 200128°F 200538%0%
May 569°F45°F86°F 200130°F 197937%0%
May 669°F46°F85°F 198235°F 198737%0%
May 769°F46°F87°F 200429°F 198937%0%
May 870°F46°F85°F 201526°F 202037%0%
May 970°F47°F86°F 201427°F 202037%0%
May 1070°F47°F86°F 199330°F 197737%0%
May 1170°F48°F86°F 197929°F 202037%0%
May 1271°F48°F88°F 201129°F 202037%0%
May 1371°F48°F86°F 198229°F 199637%0%
May 1471°F49°F86°F 198231°F 199637%0%
May 1571°F49°F88°F 198235°F 198037%0%
May 1672°F49°F89°F 198835°F 197937%0%
May 1772°F50°F89°F 199138°F 201437%0%
May 1872°F50°F88°F 198735°F 202337%0%
May 1973°F50°F89°F 197735°F 202337%0%
May 2073°F51°F90°F 197734°F 199337%0%
May 2173°F51°F90°F 197737°F 201537%0%
May 2273°F51°F89°F 197735°F 199737%0%
May 2374°F52°F88°F 202439°F 199737%0%
May 2474°F52°F88°F 202439°F 202537%0%
May 2574°F52°F90°F 197739°F 197637%0%
May 2675°F53°F90°F 201236°F 198337%0%
May 2775°F53°F91°F 201233°F 198337%0%
May 2875°F54°F92°F 201235°F 199236%0%
May 2975°F54°F92°F 201238°F 202136%0%
May 3076°F54°F90°F 198738°F 202136%0%
May 3176°F55°F89°F 199140°F 198436%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Portland, in percent, and of at least 0.1 inch of snowfall.0102030401102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (EDT).

May 1
sunrise 6:39 AM, sunset 8:36 PM
May 31
sunrise 6:12 AM, sunset 9:03 PM

Every day of May: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00127069 (Portland 1 Sw), public domain. Records: NOAA GHCN-Daily, station USC00127069, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.