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Flathead River

Flathead River Current Water Temperature and Forecast

On this page, you will find comprehensive information about the water temperature in Flathead River, including current readings, historical data and trends, monthly averages, as well as weather forecasts and upcoming temperature predictions. We find every spot where you can swim and tell you what the water temperature is there today and throughout the year.

Current Water Temperature in Flathead River

0.9°C

TODAY

0.9°C

YESTERDAY

1.1°C

A WEEK AGO

As of today, the minimum water temperature in the Flathead River ranges less than 41°F (5°C). Such water is extremely cold and not recommended for swimming without proper preparation. In these conditions, the risk of hypothermia is very high, and prolonged exposure to the water can be hazardous to your health. If you decide to swim, it is important to have the appropriate gear, such as a wetsuit. Typically, only experienced swimmers or those who practice winter swimming venture into such waters.

It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.

Analysis, Historical Data, and Forecast of Water Temperature

Water Temperature Chart for Flathead River Over the Last 30 Days

Today the water temperature in Flathead River is lower than the same day in previous years. The water temperature range here in March is from 0°C to 11°C. The water temperature is trending downward, and it has decreased both over the past 30 days and the past week.

The forecasted water temperature values for Flathead River are presented in the table below.

The actual water temperature values near the shore may differ by a few degrees from the stated values. For the development of the forecast, we use our own mathematical model that takes into account the current water temperature changes, historical data, and key weather trends, including wind strength and direction, and air temperature in each specific region.

Daily Water Temperature Chart

DateCurrentAverageForecast
Mar 221.1°C5.5°C
Mar 231.0°C5.5°C
Mar 240.0°C5.5°C
Mar 250.0°C5.5°C
Mar 260.7°C5.5°C
Mar 270.9°C5.5°C
Mar 280.9°C5.5°C
Mar 290.9°C5.5°C
Mar 305.5°C1.2°C
Mar 315.5°C1.5°C
Apr 19.9°C2.0°C
Apr 29.9°C2.5°C
Apr 39.9°C3.0°C
Apr 49.9°C3.4°C
Apr 59.9°C3.8°C
Apr 69.9°C4.2°C
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast

Water Temperature Ranges in Flathead River by Month

January

MinimumAverageMaximum
1°C5°C9°C

February

MinimumAverageMaximum
1°C5°C9°C

March

MinimumAverageMaximum
0°C5.5°C11°C

April

MinimumAverageMaximum
5°C9.9°C16°C

May

MinimumAverageMaximum
8°C13.4°C21°C

June

MinimumAverageMaximum
14°C18.5°C22°C

July

MinimumAverageMaximum
17°C20°C24°C

August

MinimumAverageMaximum
17°C21.4°C23°C

September

MinimumAverageMaximum
11°C17.6°C19°C

October

MinimumAverageMaximum
8°C13.3°C16°C

November

MinimumAverageMaximum
3°C8.1°C16°C

December

MinimumAverageMaximum
3°C4.7°C8°C

Monthly Water Temperature Histogram for Flathead River

Water Temperature in Cities and Towns on Flathead River

Columbia Falls
United States (Montana)
2.2°C
Kalispell
United States (Montana)
1.9°C
Polson
United States (Montana)
2.6°C

Flathead River Weather

MARCH 30

2°C / 10°C
slight snow shower

rain: 26% | wind: 11 km/h

MARCH 31

0°C / 11°C
overcast

rain: 40% | wind: 7 km/h

APRIL 1

2°C / 11°C
light drizzle

rain: 40% | wind: 18 km/h

APRIL 2

0°C / 8°C
light drizzle

rain: 15% | wind: 17 km/h

Water Temperature in Flathead River: General Trends and Swimming Opportunities

Source Confluence of North Fork and Middle Fork Flathead River
• location Rocky Mountains
• elevation 3,120 ft (950 m)
Mouth Clark Fork
• location Montana
• elevation 2,484 ft (757 m)
Length 158 mi (254 km)

The Flathead River, located in northwestern Montana, is a pristine waterway known for its clear waters and stunning surroundings, including Glacier National Park. Its water temperature is significantly influenced by snowmelt from nearby mountains, keeping the river cold for much of the year. During spring and early summer, temperatures often hover between 40°F and 50°F (4°C–10°C), making the water brisk and refreshing. By mid to late summer, in slower sections or areas exposed to the sun, water temperatures can reach up to 60°F–70°F (15°C–21°C), providing more comfortable conditions for recreational activities.

Swimming in the Flathead River is possible during the warmer months, especially in calmer areas like river bends or designated swimming spots near campgrounds and parks. However, the river’s strong currents and cold water make it more suited for activities like floating, kayaking, and paddleboarding. For those looking to swim, it’s best to stick to shallow, still sections and always exercise caution due to the river’s varying depths and flow rates. The Flathead River offers a unique opportunity to enjoy Montana’s natural beauty while cooling off in its refreshing waters.

Geographical Location of Flathead River

Nearby Rivers

Frequently Asked Questions About Flathead River and its Water Temperatures

What is the current water temperature in Flathead River?

The water temperature today in Flathead River ranges from 35°F (1.9°C) to 37°F (2.6°C).

What is the water temperature in Flathead River during the summer months?

The average water temperature in Flathead River during the summer months is typically between 65°F to 71°F (19°C to 21°C), and it can reach up to 75°F (24°C) at its warmest. However, in some years, the temperature may exceed this range.

What is the water temperature in Flathead River in May?

The average water temperature in Flathead River in May ranges from 46°F to 70°F (8°C to 21°C).

What is the water temperature in Flathead River in September?

The average water temperature in Flathead River in September is typically between 52°F to 66°F (11°C to 19°C).

Where does Flathead River flow?

Flathead River flows through United States (Montana), Canada (British Columbia).

Is it possible to swim in the Flathead River?

Yes, it is possible to swim in the Flathead River. However, one should always be mindful of the river's current and potential wildlife.