September weather forecast and climate
Flagstaff, AZ

The brown iconic clock tower in the city of Flagstaff, Arizona, with the street signs of Birch Avenue and San Francisco Street
The brown iconic clock tower in the city of Flagstaff, Arizona, with the street signs of Birch Avenue and San Francisco Street

Weather in September

September, the first month of the autumn, in Flagstaff, is also a moderately hot month, with temperature in the range of an average low of 53.8°F (12.1°C) and an average high of 75.2°F (24°C).

Temperature

In Flagstaff, the average high-temperature in September marginally drops, from 81°F (27.2°C) in August, to a still warm 75.2°F (24°C). In September, the average low-temperature is 53.8°F (12.1°C).

Humidity

The average relative humidity in Flagstaff is 44%.

Rainfall

In September, in Flagstaff, the rain falls for 9 days. Throughout September, 0.98" (25mm) of precipitation is accumulated. Throughout the year, in Flagstaff, there are 74.8 rainfall days, and 12.56" (319mm) of precipitation is accumulated.

Snowfall

In Flagstaff snow does not fall in June through September.

Daylight

In Flagstaff, the average length of the day is 12.4h.

Sunshine

In Flagstaff, Arizona, the average sunshine in September is 9.7h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health hazard from the exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the temperature in September in Flagstaff?

In September, the average high-temperature is 75.2°F (24°C), and the average low-temperature is 53.8°F (12.1°C).

What is the average humidity in September in Flagstaff?

In Flagstaff, Arizona, the average relative humidity in September is 44%.

How much does it rain in Flagstaff in September?

In Flagstaff, Arizona, during September, the rain falls for 9 days and regularly aggregates up to 0.98" (25mm) of precipitation.

Does it snow in Flagstaff in September?

In Flagstaff, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in Flagstaff?

In Flagstaff, Arizona, snow does not fall in June through September.

What is the average length of the day in September in Flagstaff?

In Flagstaff, the average length of the day in September is 12.4h.

How long on average sun shines in September in Flagstaff?

In Flagstaff, the average sunshine in September is 9.7h.

What is the UV index intensity in September in Flagstaff?

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from unprotected exposure to the UV radiation.

Average temperature in September
Flagstaff, AZ

Average temperature in September - Flagstaff, AZ
  • Average high temperature in September: 75.2°F

The warmest month (with the highest average high temperature) is July (82.8°F).
Months with the lowest average high temperature are January and December (42.6°F).

  • Average low temperature in September: 53.8°F

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is December (24.8°F).

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Average pressure in September
Flagstaff, AZ

Average pressure in September - Flagstaff, AZ
  • Average pressure in September: 29.94"

The month with the highest atmospheric pressure is January (30.14").
The month with the lowest atmospheric pressure is June (29.86").

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Average wind speed in September
Flagstaff, AZ

Average wind speed in September - Flagstaff, AZ
  • Average wind speed in September: 6.5mph

The windiest month (with the highest average wind speed) is April (9.6mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).

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Average humidity in September
Flagstaff, AZ

Average humidity in September - Flagstaff, AZ
  • Average humidity in September: 44%

The month with the highest relative humidity is January (66%).
The month with the lowest relative humidity is June (24%).

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Average rainfall in September
Flagstaff, AZ

Average rainfall in September - Flagstaff, AZ
  • Average rainfall in September: 0.98"

The wettest month (with the highest rainfall) is July (2.56").
The driest month (with the least rainfall) is June (0.24").

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Average rainfall days in September
Flagstaff, AZ

Average rainfall days in September - Flagstaff, AZ
  • Average rainfall days in September: 9 days

The month with the highest number of rainy days is July (16.2 days).
Months with the least rainy days are February and November (2.5 days).

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Average snowfall in September
Flagstaff, AZ

Average snowfall in September - Flagstaff, AZ
  • Average snowfall in September: 0"

The month with the highest snowfall is December (7.36").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Flagstaff, AZ

Average snowfall days in September - Flagstaff, AZ
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (7.4 days).
Months with the least snowfall days are June, July and August (0 days).

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Average daylight in September /
Average sunshine in September
Flagstaff, AZ

Average daylight in September / Average sunshine in September - Flagstaff, AZ
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.5h).
The month with the shortest days is December (Average daylight: 9.8h).

  • Average sunshine in September: 9.7h

Months with the most sunshine are June and August (Average sunshine: 12.2h).
The month with the least sunshine is December (Average sunshine: 6.8h).

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Average sunshine days in September
Flagstaff, AZ

Average sunshine days in September - Flagstaff, AZ
  • Average sunshine days in September: 17.8 days

The month with the most sunshine days is June (25.8 days).
The month with the least sunshine days is July (11.4 days).

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Average UV index in September
Flagstaff, AZ

Average UV index in September - Flagstaff, AZ
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in September
Flagstaff, AZ

Average cloud cover in September - Flagstaff, AZ
  • Average cloud cover in September: 11

The month with the most cloud cover is December (Cloud cover 24).
The month with the least cloud cover is June (Cloud cover 7).

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Average visibility in September
Flagstaff, AZ

Average visibility in September - Flagstaff, AZ
  • Average visibility in September: 6mi

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

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