September weather forecast
Montana, USA

September marks the beginning of the transition from summer to autumn in Montana, with temperatures gradually declining and the weather showing signs of change. The variations between the western and eastern regions of the state continue to be influenced by the topography and geography.

The minimum temperature in September ranges from 40°F (4.4°C) to 50°F (10°C), while the maximum temperature generally falls between 65°F (18.3°C) and 75°F (23.9°C). The cooling trend becomes more apparent, especially towards the latter part of the month.

Snow is still unlikely in September, though the highest peaks may start to see early snowfall. Rain becomes more common, particularly in the western part of the state, and thunderstorms lessen in frequency.

Compared to August, September brings a noticeable shift in weather, with shorter days and cooling temperatures signaling the approach of autumn. The landscapes begin to change as well, with leaves starting to turn color and the lush greenery of summer giving way to the hues of fall.

Tourism remains active in September, though the numbers may start to decline compared to the peak summer months. The mild weather still permits a wide range of outdoor activities, and the changing scenery adds a unique charm to the state's natural beauty.

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• Billings - September »
  On the first day of September in Billings sunrise is at 6:35 am and sunset at 7:52 pm. In Billings, in September, during 9.1 rainfall days, 0.98" (25mm) of precipitation is typically accumulated.
• Missoula - September »
  The month of September in Missoula heralds the arrival of autumn, as temperatures dalliance towards lower measurements. In Missoula, during September, the rain falls for 4.2 days and regularly aggregates up to 0.24" (6mm) of precipitation.
• Great Falls - September »
  In Great Falls, during September, the rain falls for 5.3 days and regularly aggregates up to 0.31" (8mm) of precipitation. In Great Falls, during September, the rain falls for 5.3 days and regularly aggregates up to 0.31" (8mm) of precipitation.
• Bozeman - September »
  In Bozeman during September, the rain falls for 11.2 days and regularly aggregates up to 1.81" (46mm) of precipitation. In Bozeman in September, during 11.2 rainfall days, 1.81" (46mm) of precipitation is typically accumulated.
• Butte - September »
  In Butte, during September, the rain falls for 8.5 days and regularly aggregates up to 1.06" (27mm) of precipitation. In Butte in September, it is raining for 8.5 days, with typically 1.06" (27mm) of accumulated precipitation.
• Helena - September »
  In Helena in September, during 8.1 rainfall days, 0.94" (24mm) of precipitation is typically accumulated. In Helena in September, it is raining for 8.1 days, with typically 0.94" (24mm) of accumulated precipitation.
• Kalispell - September »
  In Kalispell in September, it is raining for 8.6 days, with typically 0.91" (23mm) of accumulated precipitation. In Kalispell in September, it is raining for 8.6 days, with typically 0.91" (23mm) of accumulated precipitation.
• Havre - September »
  On the first day of September in Havre sunrise is at 6:36 am and sunset at 8:01 pm. In Havre, in September, it is raining for 7 days, with typically 1.02" (26mm) of accumulated precipitation.
• Anaconda - September »
  In Anaconda, in September, during 9.9 rainfall days, 1.18" (30mm) of precipitation is typically accumulated. In Anaconda, during September, the rain falls for 9.9 days and regularly aggregates up to 1.18" (30mm) of precipitation.
• Miles City - September »
  On the last day of September, in Miles City sunrise is at 7:00 am and sunset at 6:45 pm MDT. In Miles City in September, during 6.7 rainfall days, 0.51" (13mm) of precipitation is typically accumulated.
• Belgrade - September »
  On the first day of September in Belgrade sunrise is at 6:45 am and sunset at 8:03 pm. In Belgrade, Montana, in September, during 10.7 rainfall days, 1.42" (36mm) of precipitation is typically accumulated.
• Livingston - September »
  On the first day of September in Livingston, Montana, sunrise is at 6:43 am and sunset at 8:00 pm. On the first day of September in Livingston, sunrise is at 6:43 am and sunset at 8:00 pm.