Hillsboro, OR weather in August
August in Hillsboro: warm and mostly dry. Highs 82°F, lows 54°F, about 3 wet days. This is the peak of the warm season in Hillsboro. A good month for most outdoor plans.
- Normal high
- 82°F
- Normal low
- 54°F
- Wet days
- 3
- 0.5 in total
- Muggy days
- 0
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 84°F | 80°F |
| Normal low | 55°F | 52°F |
| Chance of a wet day | 8% | 15% |
| Sunrise / sunset | 5:56 am / 8:40 pm | 6:32 am / 7:52 pm |
| Daylight | 14.7 h | 13.3 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical August day
- 6 am55°Fdew point 51°F
- 9 am66°Fdew point 54°F
- Noon75°Fdew point 54°F
- 3 pm80°Fdew point 53°F
- 6 pm78°Fdew point 54°F
- 9 pm67°Fdew point 54°F
NOAA hourly normals (local standard time) from Portland-Hillsboro Airport (2 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F12 of 31
- Hot dayshigh 90°F or more8 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow3 of 31
- Notable rainat least 0.10 in1 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 0.5 in; a dry August brings about 0.08 in and a wet one about 0.7 in (25th and 75th percentiles). Days with half an inch or more are rare.
How August varies from year to year
- Warmest August, 1991-20201992: average high 89°F
- Coolest August2007: average high 79°F
- Wettest August2004: 1.7 in
- Driest August1998: no measurable precipitation
- Highest reading105°F (August 13, 2002)
- Lowest reading40°F (August 18, 1995)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 81°F | 82°F | 76°F |
| Normal low | 54°F | 54°F | 49°F |
| Wet days | 3 | 3 | 6 |
| Comfortable days | 13 | 12 | 16 |
| Daylight | 15.3 h | 14.1 h | 12.5 h |
Highs change by +1°F from July and -6°F into September.
Nearby alternatives in August
- Cooler: Cannon Beach, OR53 mi · high 69°F · 6 wet days
How Hillsboro ranks in August
- Normal high267th warmest of 378 cities; 4th of 6 in Oregon
- Wet days71st driest of 378
- Comfortable days50th most of 341
What to pack for Hillsboro in August
- Layers – afternoons near 82°F but nights near 54°F
- Sunglasses and sunscreen – about 14.1 hours of daylight and highs near 82°F
Heating and cooling
August has 35 heating degree days and 123 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Hillsboro in August?
The normal high is 82°F and the normal low is 54°F. From 1991 to 2020 the hottest August reading was 105°F (August 13, 2002).
Does it rain a lot in Hillsboro in August?
About 3 days in August have at least 0.01 in of precipitation, and the normal total is 0.5 in. The wettest August in 1991-2020 was in 2004 (1.7 in); the driest was in 1998, with no measurable precipitation.
Is August a good time to visit Hillsboro?
August ranks 5th of 12 months on our comfort score for Hillsboro (67 out of 100). It has about 12 comfortable days and about 8 days at 90°F or hotter. The best month is June.
Where the numbers come from
- Temperature and snow depth: Forest Grove (USC00352997), 5.5 mi W of the city center, 180 ft . NOAA normals and daily records, 1991-2020.
- Rain and snowfall: Dilley 2 S (USC00352325), 7.3 mi SW of the city center, 194 ft . NOAA normals and daily records, 1991-2020.
- Frost dates and humidity and wind by hour: Portland-Hillsboro Airport (USW00094261), 2.3 mi ENE of the city center, 204 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Portland International Airport (726980-24229), 19 mi ENE of the city center, 22 ft (173 ft lower than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).