August weather forecast
Hillsboro, OR

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The red tree colors of the fall along a road and amid trees in this tranquil neighborhood in Hillsboro, Oregon
The red tree colors of the fall along a road and amid trees in this tranquil neighborhood in Hillsboro, Oregon

Weather in August

August extends Hillsboro’s warm temperatures, from July, with high averages around 81.5°F (27.5°C). However, the dryness in the atmosphere begins to give way to increasing humidity. The rain remains rare as cloudy days become slightly more frequent compared to July, but sunshine still prevails. Meanwhile, as the city heads towards autumn, daylight hours start to gradually decrease from their peak in June and July. August signifies the end of peak summer, with relatively stable weather and a slight cooling trend setting in towards the end of the month.

Temperature

August, with an average high of 81.5°F (27.5°C) and a low of 55.4°F (13°C), signifies the warmest month of the year.

Heat index

For August, the heat index is calculated to be 84.2°F (29°C). Prolonged activity during exposure might result in a state of fatigue and cause heat cramps.
Note that heat index values are valued for light wind and location in the shade. Heat index values might soar by up to 15 Fahrenheit (8 Celsius) degrees with exposure to direct sunshine.
Note: The heat index, also known as 'feels like' or 'real feel', reflects the feeling of heat when considering both air temperature and humidity. An individual's perception of weather can be influenced by a variety of factors including metabolic differences, being pregnant, and their degree of physical exertion. Consider the fact that direct sun exposure can influence how hot one feels, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Young ones often underestimate the need for rest and rehydration. Thirst appears late in dehydration - hence, it is important to keep hydrated, particularly during prolonged physical activities.

Humidity

August is the least humid month, with an average relative humidity of 64%.

Rainfall

August is the month with the least rainfall in Hillsboro. Rain falls for 4.4 days and accumulates 0.31" (8mm) of precipitation.

Snowfall

April through October are months without snowfall.

Daylight

The average length of the day in August is 14h and 3min.
On the first day of August, sunrise is at 5:56 am and sunset at 8:39 pm. On the last day of the month, sunrise is at 6:33 am and sunset at 7:50 pm PDT.

Sunshine

The month with the most sunshine is August, with an average of 10.6h of sunshine.

UV index

In Hillsboro, Oregon, the average daily maximum UV index in August is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.
Note: A maximum UV index of 4 in August translates into the following recommendations:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
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Frequently asked questions

What month is the hottest in Hillsboro?

August, on average, is the warmest month in Hillsboro, registering a high temperature of 81.5°F (27.5°C) and a low of 55.4°F (13°C).

What is the usual temperature for Hillsboro in August?

The high-temperature, in August, in Hillsboro, records 81.5°F (27.5°C), while the low-temperature is 55.4°F (13°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, in August is calculated to be 84.2°F (29°C).

What is the least humid month in Hillsboro?

August is the least humid month in Hillsboro, with an average relative humidity of 64%.

What is the average humidity in August in Hillsboro?

In August, the average relative humidity in Hillsboro, Oregon, is 64%.

What is the driest month in Hillsboro?

The month with the least rainfall is August, when the rain falls for 4.4 days and typically collects 0.31" (8mm) of precipitation.

How many days does it rain in August in Hillsboro?

In Hillsboro, Oregon, during August, the rain falls for 4.4 days and regularly aggregates up to 0.31" (8mm) of precipitation.

When it does not snow in Hillsboro?

April through October are months without snowfall.

How many hours of daylight does Hillsboro have in August?

In August, the average day length in Hillsboro, Oregon, is 14h and 3min.

When are sunrise and sunset in August in Hillsboro?

On the first day of August in Hillsboro, sunrise is at 5:56 am and sunset at 8:39 pm. On the last day of the month, sunrise is at 6:33 am and sunset at 7:50 pm PDT.

What month has the most sunshine in Hillsboro?

With an average of 10.6h of sunshine, August has the most sunshine of the year in Hillsboro.

How long on average sun shines in August in Hillsboro?

In Hillsboro, Oregon, the average sunshine duration in August is 10.6h.

What is the UV index reading in August in Hillsboro?

In Hillsboro, Oregon, the average daily maximum UV index in August is 4. A UV Index reading of 3 to 5 represents a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Hillsboro, OR

Average temperature in August - Hillsboro, OR
  • Average high temperature in August: 81.5°F

The warmest month (with the highest average high temperature) is August (81.5°F).
The month with the lowest average high temperature is December (43.9°F).

  • Average low temperature in August: 55.4°F

The month with the highest average low temperature is August (55.4°F).
The coldest month (with the lowest average low temperature) is December (34°F).

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Average pressure in August
Hillsboro, OR

Average pressure in August - Hillsboro, OR
  • Average pressure in August: 30.01"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

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Average wind speed in August
Hillsboro, OR

Average wind speed in August - Hillsboro, OR
  • Average wind speed in August: 4.3mph

The windiest month (with the highest average wind speed) is March (5mph).
The calmest months (with the lowest average wind speed) are June, August and September (4.3mph).

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Average humidity in August
Hillsboro, OR

Average humidity in August - Hillsboro, OR
  • Average humidity in August: 64%

The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is August (64%).

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Average rainfall in August
Hillsboro, OR

Average rainfall in August - Hillsboro, OR
  • Average rainfall in August: 0.31"

The wettest month (with the highest rainfall) is January (4.57").
The driest month (with the least rainfall) is August (0.31").

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Average rainfall days in August
Hillsboro, OR

Average rainfall days in August - Hillsboro, OR
  • Average rainfall days in August: 4.4 days

The month with the highest number of rainy days is March (20.8 days).
The month with the least rainy days is August (4.4 days).

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Average snowfall in August
Hillsboro, OR

Average snowfall in August - Hillsboro, OR
  • Average snowfall in August: 0"

The month with the highest snowfall is February (1.81").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in August
Hillsboro, OR

Average snowfall days in August - Hillsboro, OR
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is February (2.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in August /
Average sunshine in August
Hillsboro, OR

Average daylight in August / Average sunshine in August - Hillsboro, OR
  • Average daylight in August: 14h and 1min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in August: 10h and 4min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).

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Average sunshine days in August
Hillsboro, OR

Average sunshine days in August - Hillsboro, OR
  • Average sunshine days in August: 24.3 days

The month with the most sunshine days is July (24.4 days).
The month with the least sunshine days is March (8.5 days).

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Average UV index in August
Hillsboro, OR

Average UV index in August - Hillsboro, OR
  • Average UV index in August: 4

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in August
Hillsboro, OR

Average cloud cover in August - Hillsboro, OR
  • Average cloud cover in August: 25

The month with the most cloud cover is February (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in August
Hillsboro, OR

Average visibility in August - Hillsboro, OR
  • Average visibility in August: 6mi

The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January and February (4mi).

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Hillsboro, Oregon, USA

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