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Average Weather in Missoula Montana, United States

In Missoula, the summers are short, warm, and mostly clear; the winters are freezing and partly cloudy; and it is dry year round. Over the course of the year, the temperature typically varies from 18°F to 87°F and is rarely below 2°F or above 96°F.

The hot season lasts for 2.7 months, from June 18 to September 10, with an average daily high temperature above 75°F. The hottest day of the year is July 27, with an average high of 87°F and low of 54°F.

The cold season lasts for 3.4 months, from November 14 to February 24, with an average daily high temperature below 41°F. The coldest day of the year is January 1, with an average low of 18°F and high of 30°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature in Missoula12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDecfreezingfreezingchillychillycoldcoldcoolcoolcomfortablecomfortablewarmwarm
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In Missoula, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Missoula begins around June 14 and lasts for 3.9 months, ending around October 10. On July 23, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 78% of the time, and overcast or mostly cloudy 22% of the time.

The cloudier part of the year begins around October 10 and lasts for 8.1 months, ending around June 14. On January 10, the cloudiest day of the year, the sky is overcast or mostly cloudy 66% of the time, and clear, mostly clear, or partly cloudy 34% of the time.

Cloud Cover

Cloud Cover in Missoulaclearerclearercloudiercloudiercloudiercloudier0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 1066%Jan 1066%Jul 2322%Jul 2322%Jun 1445%Jun 1445%Oct 1045%Oct 1045%overcastovercastpartly cloudypartly cloudymostly clearmostly clearclearclear
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Missoula varies throughout the year.

The wetter season lasts 7.5 months, from November 10 to June 25, with a greater than 26% chance of a given day being a wet day. The chance of a wet day peaks at 36% on June 4.

The drier season lasts 4.5 months, from June 25 to November 10. The smallest chance of a wet day is 15% on July 26.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Missoula changes throughout the year.

Rain alone is the most common for 11 months, from January 11 to December 9. The highest chance of a day with rain alone is 36% on June 4.

Snow alone is the most common for 1.1 months, from December 9 to January 11. The highest chance of a day with snow alone is 11% on December 24.

Daily Chance of Precipitation

Daily Chance of Precipitation in Missoularainrainsnowsnow0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJun 436%Jun 436%Jul 2615%Jul 2615%Jan 1126%Jan 1126%Dec 925%Dec 925%Nov 1026%Nov 1026%snowsnowrainrain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Missoula experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Missoula. The most rain falls during the 31 days centered around June 1, with an average total accumulation of 2.3 inches.

The least rain falls around January 22, with and average total accumulation of 0.6 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Missoula experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 4.8 months, from October 31 to March 24, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 1, with an average total liquid-equivalent accumulation of 0.7 inches.

The snowless period of the year lasts for 7.2 months, from March 24 to October 31. The least snow falls around July 30, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in Missoulasnowsnowsnowsnow0.0 in0.5 in1.0 in1.5 in2.0 in2.5 inJanFebMarAprMayJunJulAugSepOctNovDecJan 10.7 inJan 10.7 inJul 300.0 inJul 300.0 inOct 310.1 inOct 310.1 inMar 240.1 inMar 240.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Missoula varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 32 minutes of daylight; the longest day is June 21, with 15 hours, 53 minutes of daylight.

Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:40 AM on June 15, and the latest sunrise is 2 hours, 43 minutes later at 8:23 AM on November 4. The earliest sunset is at 4:47 PM on December 10, and the latest sunset is 4 hours, 47 minutes later at 9:34 PM on June 25.

Daylight saving time (DST) is observed in Missoula during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in Missoula2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDecJun 155:40 AMJun 155:40 AM9:34 PMJun 259:34 PMJun 25Dec 104:47 PMDec 104:47 PM8:23 AMNov 48:23 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daydaynightnightnightnight
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Missoula, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

Humidity Comfort Levels

Humidity Comfort Levels in Missoula0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 140%Jan 140%Jul 300%Jul 300%drydry
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Missoula does not vary significantly over the course of the year, remaining within 0.2 miles per hour of 2.3 miles per hour throughout.

Average Wind Speed

Average Wind Speed in Missoula0.0 mph0.5 mph1.0 mph1.5 mph2.0 mph2.5 mph3.0 mph3.5 mph4.0 mphJanFebMarAprMayJunJulAugSepOctNovDecJan 182.5 mphJan 182.5 mphAug 122.1 mphAug 122.1 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Missoula is from the west throughout the year.

Wind Direction

Wind Direction in Missoula0%20%40%60%80%100%JanFebMarAprMayJunJulAugSepOctNovDecwestwestsouthsoutheasteastnorthnorth
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.2 months, from May 15 to August 21, with an average daily incident shortwave energy per square meter above 6.3 kWh. The brightest day of the year is July 8, with an average of 7.6 kWh.

The darker period of the year lasts for 3.5 months, from October 28 to February 14, with an average daily incident shortwave energy per square meter below 2.6 kWh. The darkest day of the year is December 24, with an average of 1.3 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in Missoulabrightbrightdarkdarkdarkdark0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJanFebMarAprMayJunJulAugSepOctNovDecJul 87.6 kWhJul 87.6 kWhDec 241.3 kWhDec 241.3 kWhMay 156.3 kWhMay 156.3 kWhAug 216.3 kWhAug 216.3 kWhOct 282.6 kWhOct 282.6 kWhFeb 142.6 kWhFeb 142.6 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Missoula are 46.872 deg latitude, -113.994 deg longitude, and 3,264 ft elevation.

The topography within 2 miles of Missoula contains very significant variations in elevation, with a maximum elevation change of 1,870 feet and an average elevation above sea level of 3,393 feet. Within 10 miles contains very significant variations in elevation (4,846 feet). Within 50 miles also contains extreme variations in elevation (7,244 feet).

The area within 2 miles of Missoula is covered by artificial surfaces (44%), sparse vegetation (34%), and grassland (12%), within 10 miles by sparse vegetation (27%) and shrubs (27%), and within 50 miles by trees (43%) and sparse vegetation (23%).

Data Sources

This report illustrates the typical weather in Missoula, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Missoula.

For each station, the records are corrected for the elevation difference between that station and Missoula according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Missoula is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Missoula and a given station.

The stations contributing to this reconstruction are: Missoula International Airport (96%, 9 kilometers, northwest), Bert Mooney Airport (1.3%, 153 kilometers, southeast), Helena Regional Airport (1.4%, 158 kilometers, east), and Lemhi County Airport (1.0%, 196 kilometers, south).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.