Climate and Average Weather Year Round in Katmai National Park United StatesIn Katmai National Park, the summers are cool and mostly cloudy and the winters are long, freezing, snowy, windy, and partly cloudy. Over the course of the year, the temperature typically varies from 11°F to 64°F and is rarely below -19°F or above 73°F. Based on the tourism score, the best time of year to visit Katmai National Park for warm-weather activities is from mid July to mid August. Average Temperature in Katmai National ParkThe warm season lasts for 3.7 months, from May 23 to September 12, with an average daily high temperature above 57°F. The hottest month of the year in Katmai National Park is July, with an average high of 64°F and low of 48°F. The cold season lasts for 4.0 months, from November 11 to March 10, with an average daily high temperature below 33°F. The coldest month of the year in Katmai National Park is January, with an average low of 12°F and high of 26°F.
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. CloudsIn Katmai National Park, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year. The clearer part of the year in Katmai National Park begins around September 4 and lasts for 2.6 months, ending around November 21. The clearest month of the year in Katmai National Park is October, during which on average the sky is clear, mostly clear, or partly cloudy 45% of the time. The cloudier part of the year begins around November 21 and lasts for 9.4 months, ending around September 4. The cloudiest month of the year in Katmai National Park is July, during which on average the sky is overcast or mostly cloudy 64% of the time.
PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Katmai National Park varies throughout the year. The wetter season lasts 4.7 months, from July 2 to November 25, with a greater than 29% chance of a given day being a wet day. The month with the most wet days in Katmai National Park is September, with an average of 11.6 days with at least 0.04 inches of precipitation. The drier season lasts 7.3 months, from November 25 to July 2. The month with the fewest wet days in Katmai National Park is March, with an average of 5.8 days with at least 0.04 inches of precipitation. Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Katmai National Park is September, with an average of 11.5 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 41% on September 6.
RainfallTo 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. Katmai National Park experiences significant seasonal variation in monthly rainfall. Rain falls throughout the year in Katmai National Park. The month with the most rain in Katmai National Park is September, with an average rainfall of 3.1 inches. The month with the least rain in Katmai National Park is March, with an average rainfall of 0.6 inches.
SnowfallAs with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Katmai National Park experiences significant seasonal variation in monthly snowfall. The snowy period of the year lasts for 6.4 months, from October 8 to April 20, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Katmai National Park is January, with an average snowfall of 4.5 inches. The snowless period of the year lasts for 5.6 months, from April 20 to October 8. The least snow falls around July 21, with an average total accumulation of 0.0 inches.
SunThe length of the day in Katmai National Park varies extremely over the course of the year. In 2024, the shortest day is December 21, with 6 hours, 18 minutes of daylight; the longest day is June 20, with 18 hours, 22 minutes of daylight.
The earliest sunrise is at 5:10 AM on June 18, and the latest sunrise is 5 hours, 0 minutes later at 10:10 AM on December 26. The earliest sunset is at 4:25 PM on December 14, and the latest sunset is 7 hours, 7 minutes later at 11:32 PM on June 22. Daylight saving time (DST) is observed in Katmai National Park during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. HumidityWe 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 Katmai National Park, 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.
WindThis 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 Katmai National Park experiences significant seasonal variation over the course of the year. The windier part of the year lasts for 7.7 months, from September 4 to April 26, with average wind speeds of more than 10.5 miles per hour. The windiest month of the year in Katmai National Park is February, with an average hourly wind speed of 12.1 miles per hour. The calmer time of year lasts for 4.3 months, from April 26 to September 4. The calmest month of the year in Katmai National Park is June, with an average hourly wind speed of 9.0 miles per hour.
The predominant average hourly wind direction in Katmai National Park varies throughout the year. The wind is most often from the north for 1.3 months, from February 27 to April 5 and for 2.4 months, from September 19 to December 1, with a peak percentage of 41% on November 1. The wind is most often from the east for 2.0 months, from April 5 to June 6 and for 2.9 months, from December 1 to February 27, with a peak percentage of 34% on May 27. The wind is most often from the south for 2.3 months, from June 6 to August 16 and for 2.6 weeks, from September 1 to September 19, with a peak percentage of 38% on July 26. Water TemperatureKatmai National Park is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water. The average water temperature experiences significant seasonal variation over the course of the year. The time of year with warmer water lasts for 2.4 months, from July 11 to September 24, with an average temperature above 50°F. The month of the year in Katmai National Park with the warmest water is August, with an average temperature of 55°F. The time of year with cooler water lasts for 5.7 months, from November 15 to May 6, with an average temperature below 36°F. The month of the year in Katmai National Park with the coolest water is March, with an average temperature of 31°F.
Best Time of Year to VisitTo characterize how pleasant the weather is in Katmai National Park throughout the year, we compute two travel scores. The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Katmai National Park for general outdoor tourist activities is from mid July to mid August, with a peak score in the last week of July. Tourism Score in Katmai National ParkThe beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Katmai National Park for hot-weather activities is for the entire month of July, with a peak score in the third week of July. Beach/Pool Score in Katmai National ParkMethodologyFor each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed. Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies. Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more. Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter. Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter. Growing SeasonDefinitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere). The growing season in Katmai National Park typically lasts for 3.7 months (115 days), from around May 23 to around September 14, rarely starting before May 3 or after June 13, and rarely ending before August 24 or after October 3. Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F. Based on growing degree days alone, the first spring blooms in Katmai National Park should appear around June 13, only rarely appearing before May 29 or after July 5. Solar EnergyThis 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 3.1 months, from April 30 to August 1, with an average daily incident shortwave energy per square meter above 4.4 kWh. The brightest month of the year in Katmai National Park is June, with an average of 5.4 kWh. The darker period of the year lasts for 3.9 months, from October 21 to February 18, with an average daily incident shortwave energy per square meter below 1.3 kWh. The darkest month of the year in Katmai National Park is December, with an average of 0.3 kWh.
TopographyFor the purposes of this report, the geographical coordinates of Katmai National Park are 58.563 deg latitude, -154.979 deg longitude, and 0 ft elevation. The topography within 2 miles of Katmai National Park is essentially flat, with a maximum elevation change of 0 feet and an average elevation above sea level of 0 feet. Within 10 miles is also essentially flat (0 feet). Within 50 miles is also essentially flat (0 feet). The area within 2 miles of Katmai National Park is covered by shrubs (66%) and bare soil (24%), within 10 miles by shrubs (59%) and trees (12%), and within 50 miles by shrubs (50%) and water (19%). Data SourcesThis report illustrates the typical weather in Katmai National Park, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. The details of the data sources used for this report can be found on the King Salmon Airport page. DisclaimerThe information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site. We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands. We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader. Please review our full terms contained on our Terms of Service page. |