September weather forecast
Mountain View, HI

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Weather in September

September, the first month of the autumn in Mountain View, is also a moderately hot month, with an average temperature fluctuating between 70°F (21.1°C) and 75.2°F (24°C).

Temperature

With the arrival of September, Mountain View's average high-temperature registers at a still warm 75.2°F (24°C), indicating a subtle variation from the previous month. Mountain View's nights throughout September are marked by an average low temperature of 70°F (21.1°C), a minor drop from the day's high.

Humidity

In Mountain View, Hawaii, the average relative humidity in September is 79%.

Rainfall

In September, the rain falls for 19.2 days. Throughout September, 1.81" (46mm) of precipitation is accumulated. In Mountain View, during the entire year, the rain falls for 227.7 days and collects up to 27.83" (707mm) of precipitation.

Daylight

In Mountain View, the average length of the day in September is 12h and 14min.
On the first day of September, sunrise is at 6:05 am and sunset at 6:34 pm. On the last day of the month, sunrise is at 6:11 am and sunset at 6:09 pm HST.

Sunshine

The average sunshine in September is 8.8h.

UV index

The months with the highest UV index are May through December, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the average person.
Note: In September, an average UV index of 6 transforms into the following instructions:
Guard against overexposure. Protection from sun-induced harm is essential. Make an effort to avoid direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation, and note that objects like parasols or canopies might not offer full sun protection. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Updated: Jul 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

In Mountain View, 75.2°F (24°C) is the average high-temperature and 70°F (21.1°C) is the average low-temperature during September.

What is the average humidity in September?

The average relative humidity in September is 79%.

How many days does it rain in September?

In Mountain View, in September, during 19.2 rainfall days, 1.81" (46mm) of precipitation is typically accumulated.

What is the average length of the day in September?

The average day length in September is 12h and 14min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:05 am and sunset at 6:34 pm. On the last day of the month, sunrise is at 6:11 am and sunset at 6:09 pm HST.

How long on average sun shines in September?

In Mountain View, Hawaii, the average sunshine duration in September is 8.8h.

What is the month with the highest UV index?

The months with the highest UV index are May through December, with an average maximum UV index of 6.

What is the UV index reading in September?

The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Mountain View, HI

Average temperature in September - Mountain View, HI
  • Average high temperature in September: 75.2°F

The warmest month (with the highest average high temperature) is August (75.4°F).
The month with the lowest average high temperature is March (69.6°F).

  • Average low temperature in September: 70°F

The month with the highest average low temperature is September (70°F).
The coldest month (with the lowest average low temperature) is March (64°F).

Average pressure in September
Mountain View, HI

Average pressure in September - Mountain View, HI
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is April (30.05"Hg).
The months with the lowest atmospheric pressure are September and October (29.97"Hg).

Average wind speed in September
Mountain View, HI

Average wind speed in September - Mountain View, HI
  • Average wind speed in September: 7mph

The windiest month (with the highest average wind speed) is August (7.6mph).
The calmest month (with the lowest average wind speed) is October (6.7mph).

Average humidity in September
Mountain View, HI

Average humidity in September - Mountain View, HI
  • Average humidity in September: 79%

The month with the highest relative humidity is March (80%).
The months with the lowest relative humidity are January, May, June and July (78%).

Average rainfall in September
Mountain View, HI

Average rainfall in September - Mountain View, HI
  • Average rainfall in September: 1.81"

The wettest month (with the highest rainfall) is February (3.78").
The driest month (with the least rainfall) is June (1.1").

Average rainfall days in September
Mountain View, HI

Average rainfall days in September - Mountain View, HI
  • Average rainfall days in September: 19.2 days

The month with the highest number of rainy days is March (22.9 days).
The month with the least rainy days is January (13.3 days).

Average daylight in September /
Average sunshine in September
Mountain View, HI

Average daylight in September / Average sunshine in September - Mountain View, HI
  • Average daylight in September: 12h and 1min

The month with the longest days is June (Average daylight: 13h and 18min).
The month with the shortest days is December (Average daylight: 11h and 0min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is June (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).

Average sunshine days in September
Mountain View, HI

Average sunshine days in September - Mountain View, HI
  • Average sunshine days in September: 2.5 days

The month with the most sunshine days is January (12.1 days).
The month with the least sunshine days is August (1.8 days).

Average UV index in September
Mountain View, HI

Average UV index in September - Mountain View, HI
  • Average UV index in September: 6

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

Average cloud cover in September
Mountain View, HI

Average cloud cover in September - Mountain View, HI
  • Average cloud cover in September: 29

The month with the most cloud cover is March (Cloud cover 42).
The month with the least cloud cover is January (Cloud cover 26).

Average visibility in September
Mountain View, HI

Average visibility in September - Mountain View, HI
  • Average visibility in September: 6mi

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

Mountain View, Hawaii, USA

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