Climate and monthly weather forecast
Great Falls, MT

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A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana
A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana

The climate of Great Falls

Great Falls, located in Montana, USA, is primarily characterized by a mid-latitude steppe climate, designated by the Köppen climate classification as BSk. This climate type typically includes a temperature range that fluctuates widely, both throughout the year and even within single days, coupled with sparse precipitation levels.

Investigating the provided weather data, it becomes evident that there are significant shifts in temperature as the year progresses, with highs soaring to 83.1°F (28.4°C) in July and lows plummeting to 18.3°F (-7.6°C) in December and February. It underlines a climate that is markedly seasonal, shifting from chilled winters to warm summers. The majority of rainfall occurs in May and June, with amounts reaching 0.63" (16mm) and 0.87" (22mm) respectively. Notably, July is distinguished by the lowest rainfall of 0.2" (5mm), indicating a dry summer period consistent with the BSk classification.

Relative humidity shows a very mild fluctuation through the year, with the highest reading of 77% in January and the lowest of 40% in August. Similarly, cloud coverage follows a roughly analogous trend, with percentage hovering between 41% in January and 13% in July. The UV index peaks slightly at 6 during summer, specifically in the month of July, yet maintains a lower value of 2 for the rest of the year.

The best time to visit Great Falls

Given the weather data, the best time to visit Great Falls would arguably be from May to June. Within this period, visitors can enjoy warmer temperatures (ranging from 52.3°F (11.3°C) to 72.1°F (22.3°C)), alongside more daylight hours (from 13.7 to 15.9 hours). Specifically, June offers the longest daylight hours, with an impressive 15.9 hours per day. Furthermore, these months are characterized by higher levels of precipitation, contributing to a more vibrant and verdant local environment.

The worst time to visit Great Falls

Contrarily, the months of December, January, and February stand out as perhaps the least inviting times to venture to Great Falls. Winters in this region are notably cold, with temperatures dipping to a frigid low of 18.3°F (-7.6°C) in both December and February. Moreover, these months report the least daylight hours, averaging between 8.5 hours and 9 hours per day. On top of that, snowfall is considerably frequent; particularly in December, with an average of 1.06" (27mm) falling across 7.9 days.

Spring weather in Great Falls

From February to April, the weather in Great Falls begins to transition into spring. As this seasonal change occurs, the temperature gradually rises from 31.6°F (-0.2°C) to a more comfortable 52.3°F (11.3°C), while rainfall increases significantly from a mere 0.31" (8mm) to 0.55" (14mm). Additionally, daylight averages between 10.3 hours and 13.7 hours, indicating longer and brighter days.

Summer weather in Great Falls

The summer months, from May to August, are recognizable as the warmest period of the year in Great Falls. Average temperatures escalate steadily, from a comfortable 63°F (17.2°C) in May to a peak of 83.1°F (28.4°C) in July before falling slightly to 81.9°F (27.7°C) in August. During this period, the most significant level of rainfall is observed, yet July, the hottest month, records the least amount of precipitation, with just 0.2" (5mm).

Autumn weather in Great Falls

Moving into the autumn months of September to November, temperatures begin to cool, falling from 71.2°F (21.8°C) in September to a chillier 40.8°F (4.9°C) in November. Simultaneously, rainfall remains within a narrow band, fluctuating from 0.31" (8mm) in September to 0.35" (9mm) in November, which is a slight increase. The daylight gradually shortens from 12.5 hours to 9.3 hours per day during these months.

Winter weather in Great Falls

The winter period in Great Falls, spanning December through February, is hallmarked by the coldest temperatures. On average, temperatures range from 19.8°F (-6.8°C) to 31.6°F (-0.2°C), with December exhibiting the lowest readings. It is also the time when the most snowfall is accounted, with December showing the heaviest amount, averaging 1.06" (27mm) over 7.9 days.

Weather in January

In January, Great Falls, Montana sees particularly cold temperatures and notable snowfall. With a high of only 32.4°F (0.2°C), it's the chilliest month of the year. Those venturing outside should bundle up to combat the 77% relative humidity. Weather in January »

Weather in February

While February continues the winter vibes, it brings a slight increase in daylight hours when compared to January. The temperatures fluctuate between 18.3°F (-7.6°C) to 31.6°F (-0.2°C), while a record 2.09" (53mm) of snowfall blankets the town. Weather in February »

Weather in March

Transitioning from winter, March brings the onset of spring to Great Falls. Among the clear indicators of this is a substantial rise in temperature, reaching upto 43.3°F (6.3°C). This period sees a relative decrease in snowfall, while the rain tends to prevail with 0.35" (9mm) precipitated. Weather in March »

Weather in April

April is characterized by an increased interval of sunshine and warm temperatures. Temperatures rise substantially, with the mercury touching a higher 52.3°F (11.3°C). The weather in this month shifts positively compared to March with more daylight hours providing ample opportunity for outdoor activities. Weather in April »

Weather in May

May sees a noticeable increase in humidity and rainfall. The bout of precipitation is highest in this month accumulating as much as 0.63" (16mm) of rain. A comparative analysis of the declining period from May to June reveals a continued escalation in temperature, but a decrease in rainfall. Weather in May »

Weather in June

The month of June manifests the onset of the warm summer season with long sunny days. Extending sunshine hours to approximately 15.9 hours marks the apex, standing out as the month with the most daylight in Great Falls. With the approach of July, residents can anticipate the persistence of warm weather coupled with a gradual fall in humidity. Weather in June »

Weather in July

In July, Great Falls experiences its warmest weather. The city’s climate peaks with high temperatures reaching up to 83.1°F (28.4°C). Known as the apex of summer, it's the hottest period within Montana’s weather cycle. Transitioning from July to August, the temperature stays relatively steady, providing a seamless transition. Weather in July »

Weather in August

August hosts classic summer weather, albeit with a slight dip in temperature compared to July. Equipped with long hours of sunshine, reaching upto 81.9°F (27.7°C), it is a great period for water sports and beach activities. The expected weather transition from August to September is represented by a significant temperature drop and a rising trend of rainfall. Weather in August »

Weather in September

As the summer ebbs away, September brings forth fall in Great Falls. The cold snap kicks off, with the temperature taking a sharp plunge to 71.2°F (21.8°C). This month signifies a transitional phase from the dry and hot August to the wetter and cooler October. Weather in September »

Weather in October

October captures the essence of fall, accompanied by dropping temperatures and beautiful foliage. Though no significant snowfall is recorded in October, the temperature dip sets the tone for upcoming winter conditions. As the month concludes and November arrives, locals brace for lower temperatures and possible snowfall. Weather in October »

Weather in November

November welcomes the onset of winter. Citizens should be ready for a temperature drop to 40.8°F (4.9°C) compared to the previous month. As December approaches, the temperatures continue to take a dive, with heavy snowfall becoming a significant possibility. Weather in November »

Weather in December

December brings in the cold winter weather and frigid temperatures. Reaching only 30°F (-1.1°C), it's one of the chilliest periods in Great Falls, Montana. The anticipated weather shift signifies a further drop in temperature as the new year approaches. Weather in December »

Frequently asked questions

What is the most humid month?

With an average relative humidity of 77%, January is the most humid month.

How many days does it rain?

Throughout the year, there are 68.2 rainfall days, and 4.49" (114mm) of precipitation is accumulated.

When does it snow?

January through May, September through December are months with snowfall.

How much does it snow?

In Great Falls, Montana, during the entire year, snow falls for 45.4 days and aggregates up to 11.61" (295mm) of snow.

What are the months with the least sunshine?

The months with the least sunshine are January, February and December, with an average of 5.5h of sunshine.

What is the month with the lowest UV index?

The months with the lowest UV index are January through March, October through December, with an average maximum UV index of 2.

When does it snow the most?

February is the month with the most snowfall. Snow falls for 10 days and accumulates 2.09" (53mm) of snow.

When is Daylight Saving Time (DST) in Great Falls?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from MDT to MST.

What is the rainiest month?

The month with the most rainfall in Great Falls is June, when the rain falls for 8.6 days and typically aggregates up to 0.87" (22mm) of precipitation.

When it does not snow in Great Falls?

June through August are months without snowfall.

When are the longest days?

The month with the longest days is June, with an average of 15h and 54min of daylight.

What time of the year is the hottest?

Great Falls notes the warmest temperatures in July, with a average high of 83.1°F (28.4°C) and a low of 56.3°F (13.5°C).

What month has the most sunshine?

The month with the most sunshine is July, with an average of 12.1h of sunshine.

When is the highest UV index?

July is the month with the highest UV index, with an average maximum UV index of 6.

What is the least humid month in Great Falls?

With an average relative humidity of 40%, August is the least humid month in Great Falls.

What is the coldest month?

Great Falls, Montana, records the coldest temperatures in December, averaging a high of 30°F (-1.1°C) and a low of 18.3°F (-7.6°C).

What is the driest month?

December is the month with the least rainfall. Rain falls for 2.7 days and accumulates 0.16" (4mm) of precipitation.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 8h and 30min of daylight.

Average temperature
Great Falls, MT

Average temperature - Great Falls, MT

The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is December (30°F).

The month with the highest average low temperature is August (57.7°F).
The coldest months (with the lowest average low temperature) are February and December (18.3°F).

Average pressure
Great Falls, MT

Average pressure - Great Falls, MT

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed
Great Falls, MT

Average wind speed - Great Falls, MT

The windiest month (with the highest average wind speed) is November (11.4mph).
The calmest month (with the lowest average wind speed) is August (7.7mph).

Average humidity
Great Falls, MT

Average humidity - Great Falls, MT

The month with the highest relative humidity is January (77%).
The month with the lowest relative humidity is August (40%).

Average rainfall
Great Falls, MT

Average rainfall - Great Falls, MT

The wettest month (with the highest rainfall) is June (0.87").
The driest month (with the least rainfall) is December (0.16").

Average rainfall days
Great Falls, MT

Average rainfall days - Great Falls, MT

The month with the highest number of rainy days is April (9.9 days).
The month with the least rainy days is December (2.7 days).

Average snowfall
Great Falls, MT

Average snowfall - Great Falls, MT

The month with the highest snowfall is February (2.09").
The months with the least snowfall are June, July and August (0").

Average snowfall days
Great Falls, MT

Average snowfall days - Great Falls, MT

The month with the highest number of snowfall days is February (10 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight / Average sunshine
Great Falls, MT

Average daylight / Average sunshine - Great Falls, MT

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 30min).

Average sunshine days
Great Falls, MT

Average sunshine days - Great Falls, MT

The month with the most sunshine days is July (26.1 days).
The months with the least sunshine days are February and April (16.2 days).

Average UV index
Great Falls, MT

Average UV index - Great Falls, MT

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average visibility
Great Falls, MT

Average visibility - Great Falls, MT

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).

Great Falls, Montana, USA

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