Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Hillsboro's weather in September involves a mild decrease in the average high-temperature, moving down slightly from August's 81.5°F (27.5°C) to a still warm 73.9°F (23.3°C). Despite soaring daytime temperatures, Hillsboro registers a consistent average low-temperature of 51.4°F (10.8°C) in September.Humidity
In September, the average relative humidity is 70%.Rainfall
In Hillsboro, in September, it is raining for 10.1 days, with typically 1.46" (37mm) of accumulated precipitation. Throughout the year, there are 173 rainfall days, and 29.49" (749mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 31min.On the first day of the month, sunrise is at 6:34 am and sunset at 7:48 pm. On the last day of September, sunrise is at 7:10 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
In September, the average daily maximum UV index in Hillsboro is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The daily high UV index of 4 in September translates into this advice:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. Minimize direct exposure to the Sun during midday when its radiation is at its peak. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September in Hillsboro?
When it does not snow?
How many hours of daylight does Hillsboro have in September?
When are sunrise and sunset in September in Hillsboro?
How many hours of sunshine does Hillsboro have in September?
How high is the UV index in September?
Average temperature in September
Hillsboro, OR
- Average high temperature in September: 73.9°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 September: 51.4°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).
Average pressure in September
Hillsboro, OR
- Average pressure in September: 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).
Average wind speed in September
Hillsboro, OR
- Average wind speed in September: 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).
Average humidity in September
Hillsboro, OR
- Average humidity in September: 70%
The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is August (64%).
Average rainfall in September
Hillsboro, OR
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is January (4.57").
The driest month (with the least rainfall) is August (0.31").
Average rainfall days in September
Hillsboro, OR
- Average rainfall days in September: 10.1 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).
Average snowfall in September
Hillsboro, OR
- Average snowfall in September: 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").
Average snowfall days in September
Hillsboro, OR
- Average snowfall days in September: 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).
Average daylight in September /
Average sunshine in September
Hillsboro, OR
- Average daylight in September: 12h and 3min
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 September: 8h and 5min
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).
Average sunshine days in September
Hillsboro, OR
- Average sunshine days in September: 17.2 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).
Average UV index in September
Hillsboro, OR
- Average UV index in September: 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).
Average cloud cover in September
Hillsboro, OR
- Average cloud cover in September: 36
The month with the most cloud cover is February (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Hillsboro, OR
- Average visibility in September: 6mi
The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January and February (4mi).
Hillsboro, Oregon, USA
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