Fall Weather in Cape Cod United StatesDaily high temperatures decrease by 26°F, from 73°F to 48°F, rarely falling below 38°F or exceeding 81°F. Daily low temperatures decrease by 24°F, from 60°F to 36°F, rarely falling below 26°F or exceeding 67°F. For reference, on July 20, the hottest day of the year, temperatures in Cape Cod typically range from 65°F to 78°F, while on January 30, the coldest day of the year, they range from 26°F to 37°F. The figure below shows you a compact characterization of the hourly average fall temperatures. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day. CloudsThe fall in Cape Cod experiences rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 37% to 50%. The lowest chance of overcast or mostly cloudy conditions is 37% on September 5. The clearest day of the fall is September 5, with clear, mostly clear, or partly cloudy conditions 63% of the time. For reference, on May 23, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on September 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 63%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Cape Cod, the chance of a wet day over the course of the fall is rapidly increasing, starting the season at 24% and ending it at 32%. For reference, the year's highest daily chance of a wet day is 33% on December 15, and its lowest chance is 24% on September 3. Over the course of the fall in Cape Cod, the chance of a day with only rain increases from 24% to 29%, the chance of a day with mixed snow and rain increases from 0% to 2%, and the chance of a day with only snow remains an essentially constant 0% throughout. RainfallTo show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day rainfall during the fall in Cape Cod is rapidly increasing, starting the season at 3.2 inches, when it rarely exceeds 5.4 inches or falls below 1.2 inches, and ending the season at 4.2 inches, when it rarely exceeds 6.8 inches or falls below 1.9 inches. The highest average 31-day accumulation is 4.2 inches on November 26. SnowfallAs with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day snowfall during the fall in Cape Cod is increasing, starting the season at -0.0 inches, when it rarely exceeds 0.0 inches or falls below -0.0 inches, and ending the season at 1.0 inches, when it rarely exceeds 3.3 inches or falls below -0.0 inches. SunOver the course of the fall in Cape Cod, the length of the day is very rapidly decreasing. From the start to the end of the season, the length of the day decreases by 3 hours, 42 minutes, implying an average daily decrease of 2 minutes, 28 seconds, and weekly decrease of 17 minutes, 18 seconds. The shortest day of the fall is November 30, with 9 hours, 24 minutes of daylight and the longest day is September 1, with 13 hours, 6 minutes of daylight. The earliest sunrise of the fall in Cape Cod is 6:07 AM on September 1 and the latest sunrise is 1 hour, 7 minutes later at 7:14 AM on November 2. The latest sunset is 7:13 PM on September 1 and the earliest sunset is 3 hours, 2 minutes earlier at 4:11 PM on November 30. Daylight saving time (DST) starts at 1:00 AM on November 3, 2024, shifting sunrise and sunset to be an hour later. For reference, on June 20, the longest day of the year, the Sun rises at 5:06 AM and sets 15 hours, 12 minutes later, at 8:18 PM, while on December 21, the shortest day of the year, it rises at 7:04 AM and sets 9 hours, 9 minutes later, at 4:13 PM. 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 the fall of 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon. 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 chance that a given day will be muggy in Cape Cod is rapidly decreasing during the fall, falling from 19% to 0% over the course of the season. For reference, on August 1, the muggiest day of the year, there are muggy conditions 41% of the time, while on December 12, the least muggy day of the year, there are muggy conditions 0% of the time. 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 Cape Cod is very rapidly increasing during the fall, increasing from 10.4 miles per hour to 15.5 miles per hour over the course of the season. For reference, on January 13, the windiest day of the year, the daily average wind speed is 16.7 miles per hour, while on July 24, the calmest day of the year, the daily average wind speed is 9.5 miles per hour. The wind direction in Cape Cod during the fall is predominantly out of the south from September 1 to October 6 and the west from October 6 to November 30. Water TemperatureCape Cod 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 surface water temperature in Cape Cod is very rapidly decreasing during the fall, falling by 17°F, from 65°F to 48°F, over the course of the season. 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 Cape Cod typically lasts for 6.9 months (210 days), from around April 14 to around November 10, rarely starting before March 25 or after May 2, and rarely ending before October 21 or after November 29. During the fall in Cape Cod, the chance that a given day is within the growing season is very rapidly decreasing falling from 100% to 8% over the course of the season. 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. The average accumulated growing degree days in Cape Cod are rapidly increasing during the fall, increasing by 625°F, from 1,863°F to 2,488°F, over the course of the season. 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 in Cape Cod is very rapidly decreasing during the fall, falling by 3.7 kWh, from 5.5 kWh to 1.8 kWh, over the course of the season. TopographyFor the purposes of this report, the geographical coordinates of Cape Cod are 41.686 deg latitude, -70.243 deg longitude, and 0 ft elevation. The topography within 2 miles of Cape Cod 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 Cape Cod is covered by artificial surfaces (53%) and trees (41%), within 10 miles by water (61%) and artificial surfaces (21%), and within 50 miles by water (80%) and trees (12%). Data SourcesThis report illustrates the typical weather in Cape Cod, 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 Provincetown Municipal 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. |