Climate averages 1991–2020
Hillsboro weather
in May.
A mild, moderately wet month: the 5th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Hillsboro: daytime highs average 18.6°C and nights cool to about 8.4°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 69 mm of rain on roughly 11 days, which makes May a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 52 min on an average May day.
The nearest other city in this atlas is Beaverton (15 km away). In May its highs average 18.5°C, about as warm as Hillsboro, with 70 mm of rain.
Among the 498 cities listed in the United States, Hillsboro ranks joint 458th of 498 for the warmest May highs and joint 180th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; Hillsboro is 5.2°C cooler than that mean.
From May to June, average highs rise by 2.9°C to 21.5°C, and monthly rainfall falls from 69 mm to 40 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Hillsboro climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.9°C1.8°C | 1.8°C | 172 | 17.1 | 9.19 h |
| February | 9.7°C2.1°C | 2.1°C | 133 | 14.4 | 10.310 h |
| March | 12.1°C3.5°C | 3.5°C | 151 | 17.3 | 11.912 h |
| April | 14.6°C5.2°C | 5.2°C | 115 | 15.6 | 13.513 h |
| May, selected | 18.6°C8.4°C | 8.4°C | 69 | 10.6 | 14.915 h |
| June | 21.5°C11.0°C | 11.0°C | 40 | 7.2 | 15.616 h |
| July | 26.6°C13.8°C | 13.8°C | 11 | 2.2 | 15.315 h |
| August | 27.1°C14.4°C | 14.4°C | 13 | 2.5 | 14.114 h |
| September | 23.7°C12.2°C | 12.2°C | 43 | 6.0 | 12.613 h |
| October | 16.7°C8.0°C | 8.0°C | 107 | 11.5 | 11.011 h |
| November | 10.7°C4.2°C | 4.2°C | 179 | 17.3 | 9.610 h |
| December | 7.4°C1.7°C | 1.7°C | 204 | 17.5 | 8.89 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Beaverton in MayUnited States · 15 kmHigh 18.5°C · Low 8.3°C · 70 mm rain
- Portland in MayUnited States · 24 kmHigh 18.8°C · Low 8.8°C · 70 mm rain
- Vancouver, United States in MayUnited States · 29 kmHigh 18.5°C · Low 8.5°C · 89 mm rain
- Gresham in MayUnited States · 44 kmHigh 17.8°C · Low 7.9°C · 89 mm rain
- Salem, United States in MayUnited States · 65 kmHigh 18.6°C · Low 8.2°C · 56 mm rain
- Eugene in MayUnited States · 164 kmHigh 18.0°C · Low 7.8°C · 82 mm rain
- Tacoma in MayUnited States · 197 kmHigh 17.2°C · Low 8.4°C · 61 mm rain
- Federal Way in MayUnited States · 207 kmHigh 16.7°C · Low 7.7°C · 78 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Hillsboro) is explained once on the Hillsboro year overview and on the Sources, method and limits page.