Portland weather in May: Portland, Oregon: normal highs, lows, rain and records for May
Portland in May has a normal high of 69°F and a normal low of 49°F, a daily mean of 59°F, rising from 66°F on the 1st to 72°F by the 31st. Measurable precipitation falls on 13 days in a normal May, 2.51 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 21°C and low of 10°C, 64 mm of precipitation in May.
- NOAA stationPortland International Airport
- Station IDUSW00024229
- Location45.59°N 122.60°W
- Elevation19 ft (6 m)
- From the center4 miles
- Population635,749
- Jan 48° 36°
- Feb 52° 37°
- Mar 57° 40°
- Apr 62° 44°
- May 69° 49°
- Jun 74° 54°
- Jul 82° 59°
- Aug 82° 59°
- Sep 77° 54°
- Oct 64° 47°
- Nov 54° 41°
- Dec 47° 36°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Portland in May?
The normal high is 69°F and the normal low 49°F, for a daily mean of 59.4°F. May is 6.6°F warmer than April and 4.8°F cooler than June. May is the 5th warmest month of the year in Portland and the 8th wettest. Across the month the normal high rises 6°F, from 66°F on May 1 to 72°F on May 31. From one year to the next May's mean temperature typically moves about 2.7°F either way (NOAA's standard deviation), so roughly two Mays in three average between 57°F and 62°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 50%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 66°F | 46°F | 50% | 26% |
| May 8 | 68°F | 48°F | 46% | 24% |
| May 15 | 69°F | 49°F | 44% | 24% |
| May 22 | 71°F | 51°F | 42% | 22% |
| May 31 | 72°F | 52°F | 38% | 20% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 66°F | 46°F | 50% | 26% | 14 h 20 min |
| May 2 | 66°F | 47°F | 50% | 26% | 14 h 20 min |
| May 3 | 67°F | 47°F | 49% | 26% | 14 h 20 min |
| May 4 | 67°F | 47°F | 49% | 25% | 14 h 20 min |
| May 5 | 67°F | 47°F | 48% | 25% | 14 h 30 min |
| May 6 | 67°F | 47°F | 47% | 25% | 14 h 30 min |
| May 7 | 68°F | 48°F | 47% | 25% | 14 h 30 min |
| May 8 | 68°F | 48°F | 46% | 24% | 14 h 30 min |
| May 9 | 68°F | 48°F | 46% | 24% | 14 h 40 min |
| May 10 | 68°F | 48°F | 46% | 24% | 14 h 40 min |
| May 11 | 69°F | 49°F | 45% | 24% | 14 h 40 min |
| May 12 | 69°F | 49°F | 45% | 24% | 14 h 40 min |
| May 13 | 69°F | 49°F | 45% | 24% | 14 h 50 min |
| May 14 | 69°F | 49°F | 44% | 24% | 14 h 50 min |
| May 15 | 69°F | 49°F | 44% | 24% | 14 h 50 min |
| May 16 | 70°F | 50°F | 44% | 23% | 14 h 50 min |
| May 17 | 70°F | 50°F | 43% | 23% | 15 h |
| May 18 | 70°F | 50°F | 43% | 23% | 15 h |
| May 19 | 70°F | 50°F | 43% | 23% | 15 h |
| May 20 | 70°F | 50°F | 42% | 23% | 15 h |
| May 21 | 70°F | 51°F | 42% | 23% | 15 h 10 min |
| May 22 | 71°F | 51°F | 42% | 22% | 15 h 10 min |
| May 23 | 71°F | 51°F | 41% | 22% | 15 h 10 min |
| May 24 | 71°F | 51°F | 41% | 22% | 15 h 10 min |
| May 25 | 71°F | 51°F | 41% | 22% | 15 h 10 min |
| May 26 | 71°F | 51°F | 40% | 21% | 15 h 20 min |
| May 27 | 71°F | 52°F | 40% | 21% | 15 h 20 min |
| May 28 | 71°F | 52°F | 39% | 21% | 15 h 20 min |
| May 29 | 71°F | 52°F | 39% | 21% | 15 h 20 min |
| May 30 | 72°F | 52°F | 39% | 20% | 15 h 20 min |
| May 31 | 72°F | 52°F | 38% | 20% | 15 h 20 min |
- Normal high
- 69°FMay average
- Normal low
- 49°FMay average
- Precipitation
- 2.51 inmonth total
- Days with precipitation
- 130.01 inch or more
- Daylight
- 14 h 20 min to 15 h 20 minMay 1 to May 31
- Days at 70°F or more
- 13
- Days at 80°F or more
- 5
- Sunshine
- 68%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024229; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Portland in May?
On a given May day the chance of 0.01 inch or more is 44% on average, highest around May 1 (50%). In all, 2.51 in falls on 13 days of a normal May.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024229.
How humid and windy is Portland in May?
At 3 p.m. the normal temperature is 70°F with 47% relative humidity and a dew point of 49°F; at 6 a.m. it is 54°F with 82% humidity. The wind averages 6.6 mph, most often from the west-northwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 54°F | 49°F | 82% | 4.7 mph | – |
| 9 a.m. | 59°F | 49°F | 69% | 5.6 mph | – |
| noon | 66°F | 49°F | 55% | 7.5 mph | 25% |
| 3 p.m. | 70°F | 49°F | 47% | 8.6 mph | 22% |
| 6 p.m. | 68°F | 49°F | 51% | 8.9 mph | 23% |
| 9 p.m. | 61°F | 49°F | 65% | 7.4 mph | 32% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024229. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in Portland?
The warmest May temperature on Portland's official record (since 1940) is 100°F, on May 28, 1983; the coldest is 29°F, on May 1, 1954. The wettest May brought 5.55 in (1998).
The May mean against the 1991-2020 normal of 59.4°F: 2021 60.1°F (+0.7), 2022 56.9°F (−2.5), 2023 64.3°F (+4.9), 2024 59.3°F (−0.1), 2025 60.1°F (+0.7), 2026 61.6°F (+2.3). 4 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.1°F | +0.7°F | 0.58 in |
| 2022 | 56.9°F | −2.5°F | 3.78 in |
| 2023 | 64.3°F | +4.9°F | 0.91 in |
| 2024 | 59.3°F | −0.1°F | 2.44 in |
| 2025 | 60.1°F | +0.7°F | 1.92 in |
| 2026 | 61.6°F | +2.3°F | 0.65 in |
Source: records: ACIS, NWS threaded record PDXthr; recent months: ACIS, station USW00024229. Records and recent months use complete months only.
How does May in Portland compare across Oregon?
Across the 105 places PlainClimate covers in Oregon, May normal highs run from 54°F in Government Camp to 76°F in Ontario; Portland's is 69°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.