Hillsboro weather in May: Hillsboro, Oregon: normal highs, lows, rain and records for May
Hillsboro in May has a normal high of 69°F and a normal low of 45°F, a daily mean of 57°F, rising from 65°F on the 1st to 71°F by the 31st. Measurable precipitation falls on 12 days in a normal May, 2.02 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 20°C and low of 7°C, 51 mm of precipitation in May.
- NOAA stationPortland-Hillsboro Airport
- Station IDUSW00094261
- Location45.54°N 122.95°W
- Elevation204 ft (62 m)
- Population110,337
- Jan 47° 34°
- Feb 51° 34°
- Mar 56° 37°
- Apr 61° 39°
- May 69° 45°
- Jun 74° 49°
- Jul 82° 52°
- Aug 82° 52°
- Sep 76° 48°
- Oct 64° 41°
- Nov 53° 37°
- Dec 46° 33°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Hillsboro in May?
The normal high is 69°F and the normal low 45°F, for a daily mean of 56.7°F. May is 6.6°F warmer than April and 4.3°F cooler than June. May is the 5th warmest month of the year in Hillsboro and the 8th wettest. Across the month the normal high rises 6°F, from 65°F on May 1 to 71°F on May 31. From one year to the next May's mean temperature typically moves about 2.5°F either way (NOAA's standard deviation), so roughly two Mays in three average between 54°F and 59°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 45%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 65°F | 42°F | 45% | 22% |
| May 8 | 67°F | 43°F | 41% | 21% |
| May 15 | 69°F | 45°F | 39% | 20% |
| May 22 | 70°F | 46°F | 38% | 19% |
| May 31 | 71°F | 47°F | 35% | 18% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 30, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 65°F | 42°F | 45% | 22% | 14 h 20 min |
| May 2 | 66°F | 42°F | 44% | 22% | 14 h 20 min |
| May 3 | 66°F | 42°F | 44% | 22% | 14 h 20 min |
| May 4 | 66°F | 42°F | 43% | 22% | 14 h 20 min |
| May 5 | 67°F | 42°F | 43% | 21% | 14 h 30 min |
| May 6 | 67°F | 43°F | 42% | 21% | 14 h 30 min |
| May 7 | 67°F | 43°F | 42% | 21% | 14 h 30 min |
| May 8 | 67°F | 43°F | 41% | 21% | 14 h 30 min |
| May 9 | 68°F | 43°F | 41% | 21% | 14 h 40 min |
| May 10 | 68°F | 44°F | 41% | 21% | 14 h 40 min |
| May 11 | 68°F | 44°F | 40% | 20% | 14 h 40 min |
| May 12 | 68°F | 44°F | 40% | 20% | 14 h 40 min |
| May 13 | 69°F | 44°F | 40% | 20% | 14 h 50 min |
| May 14 | 69°F | 45°F | 40% | 20% | 14 h 50 min |
| May 15 | 69°F | 45°F | 39% | 20% | 14 h 50 min |
| May 16 | 69°F | 45°F | 39% | 20% | 14 h 50 min |
| May 17 | 69°F | 45°F | 39% | 20% | 15 h |
| May 18 | 69°F | 45°F | 39% | 20% | 15 h |
| May 19 | 70°F | 46°F | 39% | 20% | 15 h |
| May 20 | 70°F | 46°F | 38% | 20% | 15 h |
| May 21 | 70°F | 46°F | 38% | 20% | 15 h 10 min |
| May 22 | 70°F | 46°F | 38% | 19% | 15 h 10 min |
| May 23 | 70°F | 46°F | 38% | 19% | 15 h 10 min |
| May 24 | 70°F | 46°F | 37% | 19% | 15 h 10 min |
| May 25 | 70°F | 47°F | 37% | 19% | 15 h 10 min |
| May 26 | 70°F | 47°F | 37% | 19% | 15 h 20 min |
| May 27 | 70°F | 47°F | 36% | 19% | 15 h 20 min |
| May 28 | 71°F | 47°F | 36% | 18% | 15 h 20 min |
| May 29 | 71°F | 47°F | 36% | 18% | 15 h 20 min |
| May 30 | 71°F | 47°F | 35% | 18% | 15 h 20 min |
| May 31 | 71°F | 47°F | 35% | 18% | 15 h 20 min |
- Normal high
- 69°FMay average
- Normal low
- 45°FMay average
- Precipitation
- 2.02 inmonth total
- Days with precipitation
- 120.01 inch or more
- Nights at 32°F or colder
- 1
- Daylight
- 14 h 20 min to 15 h 20 minMay 1 to May 31
- Days at 70°F or more
- 12
- Days at 80°F or more
- 4
- Sunshine
- 68%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094261; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Hillsboro in May?
On a given May day the chance of 0.01 inch or more is 39% on average, highest around May 1 (45%). In all, 2.02 in falls on 12 days of a normal May.
In a normal May in Hillsboro, 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094261.
How humid and windy is Hillsboro in May?
At 3 p.m. the normal temperature is 69°F with 49% relative humidity and a dew point of 50°F; at 6 a.m. it is 52°F with 87% humidity. The wind averages 5.0 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. | 52°F | 48°F | 87% | 2.0 mph | 44% |
| 9 a.m. | 60°F | 49°F | 67% | 3.9 mph | 42% |
| noon | 66°F | 49°F | 55% | 5.3 mph | 43% |
| 3 p.m. | 69°F | 50°F | 49% | 7.0 mph | 48% |
| 6 p.m. | 67°F | 49°F | 53% | 8.5 mph | 50% |
| 9 p.m. | 58°F | 49°F | 70% | 6.2 mph | 57% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094261. 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 Hillsboro?
The warmest May temperature on Hillsboro's official record (since 1929) is 100°F, on May 29, 1983; the coldest is 26°F, on May 8, 1935. The wettest May brought 4.77 in (1998).
The May mean against the 1991-2020 normal of 56.7°F: 2021 56.8°F (+0.1), 2022 53.2°F (−3.5), 2023 61.1°F (+4.4), 2024 55.2°F (−1.5), 2025 56.9°F (+0.2), 2026 59.2°F (+2.5). 4 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 56.8°F | +0.1°F | 0.49 in |
| 2022 | 53.2°F | −3.5°F | 4.05 in |
| 2023 | 61.1°F | +4.4°F | 0.89 in |
| 2024 | 55.2°F | −1.5°F | 2.46 in |
| 2025 | 56.9°F | +0.2°F | 0.76 in |
| 2026 | 59.2°F | +2.5°F | 0.71 in |
Source: records: ACIS, NWS threaded record HIOthr; recent months: ACIS, station USW00094261. Records and recent months use complete months only.
How does May in Hillsboro 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; Hillsboro's is 69°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.