September weather forecast
Pomona Heights, WA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Pomona Heights, Washington, with temperature in the range of an average low of 51.8°F (11°C) and an average high of 74.1°F (23.4°C).

Temperature

The average high-temperature drops in September, from August's 85.1°F (29.5°C) to a still moderately hot 74.1°F (23.4°C). September is characterized by a distinct thermal shift, with nighttime lows averaging at a cool 51.8°F (11°C).

Humidity

In Pomona Heights, the average relative humidity in September is 50%.

Rainfall

In Pomona Heights, during September, the rain falls for 4.8 days and regularly aggregates up to 0.28" (7mm) of precipitation. Throughout the year, there are 87.6 rainfall days, and 5.94" (151mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, September, November and December. September is the first month it typically snows in Pomona Heights. Throughout September, in the average 0.1 snowfall days, it receives 0.12" (3mm) of snow. Throughout the year, there are 19.9 snowfall days, and 8.62" (219mm) of snow is accumulated.

Daylight

In Pomona Heights, the average length of the day in September is 12h and 32min.
On the first day of September, sunrise is at 6:22 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:42 pm PDT.

Sunshine

The average sunshine in September is 11.1h.

UV index

In Pomona Heights, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the average person.
Note: In September, an average UV index of 4 transforms into the following instructions:
Be vigilant - Suggestions to stave off sun damage are provided. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.

Frequently asked questions

What is the temperature in September?

The average high-temperature and low-temperature during September are 74.1°F (23.4°C) and 51.8°F (11°C) respectively. In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is estimated at 84.2°F (29°C).

What is the average humidity in September?

In Pomona Heights, the average relative humidity in September is 50%.

How much does it rain in September?

In Pomona Heights, in September, it is raining for 4.8 days, with typically 0.28" (7mm) of accumulated precipitation.

When does it start to snow in Pomona Heights?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.12" (3mm) of snow.

What is the average length of the day in September?

The average day length in September is 12h and 32min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:22 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:42 pm PDT.

How long on average sun shines in September?

In September, the average sunshine duration is 11.1h.

How high is the UV index in September?

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health risk from unprotected exposure to UV radiation.
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 September
Pomona Heights, WA

Average temperature in September - Pomona Heights, WA
  • Average high temperature in September: 74.1°F

The warmest month (with the highest average high temperature) is August (85.1°F).
The month with the lowest average high temperature is December (36°F).

  • Average low temperature in September: 51.8°F

The month with the highest average low temperature is August (58.8°F).
The coldest month (with the lowest average low temperature) is December (23.9°F).

Average pressure in September
Pomona Heights, WA

Average pressure in September - Pomona Heights, WA
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.93"Hg).

Average wind speed in September
Pomona Heights, WA

Average wind speed in September - Pomona Heights, WA
  • Average wind speed in September: 6.1mph

The windiest month (with the highest average wind speed) is June (7.4mph).
The calmest month (with the lowest average wind speed) is December (4.2mph).

Average humidity in September
Pomona Heights, WA

Average humidity in September - Pomona Heights, WA
  • Average humidity in September: 50%

The month with the highest relative humidity is January (83%).
The months with the lowest relative humidity are July and August (41%).

Average rainfall in September
Pomona Heights, WA

Average rainfall in September - Pomona Heights, WA
  • Average rainfall in September: 0.28"

The wettest month (with the highest rainfall) is December (0.87").
The driest month (with the least rainfall) is July (0.08").

Average rainfall days in September
Pomona Heights, WA

Average rainfall days in September - Pomona Heights, WA
  • Average rainfall days in September: 4.8 days

The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is July (2.3 days).

Average snowfall in September
Pomona Heights, WA

Average snowfall in September - Pomona Heights, WA
  • Average snowfall in September: 0.12"

The month with the highest snowfall is December (3.07").
The months with the least snowfall are May, June, July, August and October (0").

Average snowfall days in September
Pomona Heights, WA

Average snowfall days in September - Pomona Heights, WA
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (5.7 days).
The months with the least snowfall days are May, June, July, August and October (0 days).

Average daylight in September /
Average sunshine in September
Pomona Heights, WA

Average daylight in September / Average sunshine in September - Pomona Heights, WA
  • Average daylight in September: 12h and 3min

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

  • Average sunshine in September: 11h and 1min

The months with the most sunshine are July and August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 30min).

Average sunshine days in September
Pomona Heights, WA

Average sunshine days in September - Pomona Heights, WA
  • Average sunshine days in September: 23.2 days

The month with the most sunshine days is July (27.6 days).
The month with the least sunshine days is February (15.5 days).

Average UV index in September
Pomona Heights, WA

Average UV index in September - Pomona Heights, WA
  • 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
Pomona Heights, WA

Average cloud cover in September - Pomona Heights, WA
  • Average cloud cover in September: 15

The month with the most cloud cover is January (Cloud cover 40).
The months with the least cloud cover are July and August (Cloud cover 9).

Average visibility in September
Pomona Heights, WA

Average visibility in September - Pomona Heights, WA
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Pomona Heights, Washington, USA

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