September weather forecast
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 still a warm month, with an average temperature ranging between max 75.2°F (24°C) and min 53.8°F (12.1°C).

Temperature

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

Humidity

The average relative humidity in September is 44%.

Rainfall

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

Snowfall

June through September are months without snowfall.

Daylight

In September, the average length of the day in Flagstaff is 12h and 23min.
On the first day of September, sunrise is at 5:59 am and sunset at 6:54 pm. On the last day of the month, sunrise is at 6:20 am and sunset at 6:12 pm MST.

Sunshine

The average sunshine in September in Flagstaff is 9.7h.

UV index

In Flagstaff, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 5 in September transform into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. 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 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). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in August is evaluated at 80.6°F (27°C).

What is the average humidity in September in Flagstaff?

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

How many days does it rain in September in Flagstaff?

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

When it does not snow in Flagstaff?

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

Does it snow in Flagstaff in September?

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

How many hours of daylight does Flagstaff have in September?

In September, the average day length in Flagstaff is 12h and 23min.

What time are sunrise and sunset in September in Flagstaff?

In September, on the first day of the month, sunrise is at 5:59 am and sunset at 6:54 pm. On the last day of the month, sunrise is at 6:20 am and sunset at 6:12 pm MST.

How long on average sun shines in September in Flagstaff?

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

What is the UV index intensity in September in Flagstaff?

The average daily maximum UV index in September in Flagstaff is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

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).
The 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"Hg

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

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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).
The 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").
The 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).
The 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: 12h and 23min

The month with the longest days is June (Average daylight: 14h and 29min).
The month with the shortest days is December (Average daylight: 9h and 50min).

  • Average sunshine in September: 9h and 42min

The months with the most sunshine are June and August (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 48min).

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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

The months with the highest UV index are June, July and August (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 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

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).

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