September weather forecast and climate
Gallatin Gateway, MT

The first month of the autumn, September, is still a comfortable month in Gallatin Gateway, Montana, with average temperature ranging between max 65.3°F (18.5°C) and min 40.5°F (4.7°C).

Temperature

In Gallatin Gateway, Montana, the average high-temperature drops, from a warm 75.6°F (24.2°C) in August, to a comfortable 65.3°F (18.5°C). In September, the average low-temperature is 40.5°F (4.7°C).

Humidity

The average relative humidity in Gallatin Gateway is 56%.

Rainfall

In September, the rain falls for 11.2 days. Throughout September, 1.81" (46mm) of precipitation is accumulated. Throughout the year, there are 131 rainfall days, and 23.15" (588mm) of precipitation is accumulated.

Snowfall

January through June, September through December are months with snowfall in Gallatin Gateway, Montana. September is the first month it typically snows. Throughout September, in the average 1.5 snowfall days, it receives 2.05" (52mm) of snow. Throughout the year, in Gallatin Gateway, there are 122.8 snowfall days, and 91.1" (2314mm) of snow is accumulated.

Daylight

In Gallatin Gateway, the average length of the day in September is 12.5h.

Sunshine

The average sunshine in Gallatin Gateway, Montana, is 9.6h.

UV index

The average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to the UV radiation for the average person.
Note: The daily maximum UV index of 3 interpret into the following advice:
Take precautions - Protection against the 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.

What is the temperature in September in Gallatin Gateway?

In September, in Gallatin Gateway, the average high-temperature is 65.3°F (18.5°C), and the average low-temperature is 40.5°F (4.7°C).

What is the average humidity in September in Gallatin Gateway?

The average relative humidity in September is 56%.

How much does it rain in Gallatin Gateway in September?

In September, in Gallatin Gateway, Montana, the rain falls for 11.2 days. Throughout September, 1.81" (46mm) of precipitation is accumulated.

When does it start to snow in Gallatin Gateway?

September is the first month it typically snows in Gallatin Gateway, Montana. Throughout September, in the average 1.5 snowfall days, it receives 2.05" (52mm) of snow.

What is the average length of the day in September in Gallatin Gateway?

In September, the average length of the day is 12.5h.

How many hours of sunshine does Gallatin Gateway have in September?

The average sunshine in September in Gallatin Gateway, Montana, is 9.6h.

What is the UV index intensity in September in Gallatin Gateway?

In Gallatin Gateway, Montana, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate health threat from unsafe exposure to the Sun's UV rays.
Average temperature in September - Gallatin Gateway, MT
  • Average high temperature in September: 18.5°C

The warmest month (with the highest average high temperature) is July (25°C).
The month with the lowest average high temperature is December (-4°C).

  • Average low temperature in September: 4.7°C

Months with the highest average low temperature are July and August (8.3°C).
The coldest month (with the lowest average low temperature) is December (-12°C).

Average pressure in September - Gallatin Gateway, MT
  • Average pressure in September: 1015.3mbar

The month with the highest atmospheric pressure is January (1022.4mbar).
The month with the lowest atmospheric pressure is June (1012.6mbar).

Average wind speed in September - Gallatin Gateway, MT
  • Average wind speed in September: 7.9km/h

The windiest month (with the highest average wind speed) is January (9.9km/h).
The calmest month (with the lowest average wind speed) is August (7.5km/h).

Average humidity in September - Gallatin Gateway, MT
  • Average humidity in September: 56%

The month with the highest relative humidity is February (90%).
The month with the lowest relative humidity is August (51%).

Average rainfall in September - Gallatin Gateway, MT
  • Average rainfall in September: 46mm

The wettest month (with the highest rainfall) is May (72mm).
The driest month (with the least rainfall) is August (33mm).

Average rainfall days in September - Gallatin Gateway, MT
  • Average rainfall days in September: 11.2 days

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is January (4.4 days).

Average snowfall in September - Gallatin Gateway, MT
  • Average snowfall in September: 52mm

The month with the highest snowfall is February (394mm).
Months with the least snowfall are July and August (0mm).

Average snowfall days in September - Gallatin Gateway, MT
  • Average snowfall days in September: 1.5 days

The month with the highest number of snowfall days is February (20.3 days).
The month with the least snowfall days is July (0 days).

Average daylight in September / Average sunshine in September - Gallatin Gateway, MT
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.6h).
The month with the shortest days is December (Average daylight: 8.8h).

  • Average sunshine in September: 9.6h

The month with the most sunshine is July (Average sunshine: 11.5h).
Months with the least sunshine are January and February (Average sunshine: 4.5).

Average sunshine days in September - Gallatin Gateway, MT
  • Average sunshine days in September: 16.3 days

The month with the most sunshine days is September (16.3 days).
The month with the least sunshine days is April (7 days).

Average UV index in September - Gallatin Gateway, MT
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
Months with the lowest UV index are January, February, March, November and December (UV index 1).

Average cloud cover in September - Gallatin Gateway, MT
  • Average cloud cover in September: 24

The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 17).

Average visibility in September - Gallatin Gateway, MT
  • Average visibility in September: 9km

Months with the highest visibility are July and August (10km).
Months with the lowest visibility are January and February (6km).