Spring Weather in Cape Cod United States

Daily high temperatures increase by 26°F, from 41°F to 67°F, rarely falling below 32°F or exceeding 76°F.

Daily low temperatures increase by 24°F, from 29°F to 53°F, rarely falling below 19°F or exceeding 59°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 spring 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.

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The spring in Cape Cod experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 53% throughout the season. The highest chance of overcast or mostly cloudy conditions is 55% on May 23.

The clearest day of the spring is March 30, with clear, mostly clear, or partly cloudy conditions 48% 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%.

A 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 spring is essentially constant, remaining around 30% throughout.

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 spring in Cape Cod, the chance of a day with only rain increases from 23% to 32%, the chance of a day with mixed snow and rain decreases from 7% to 0%, and the chance of a day with only snow decreases from 2% to 0%.

Rainfall

To 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 spring in Cape Cod is essentially constant, remaining about 3.6 inches throughout, and rarely exceeding 6.5 inches or falling below 1.5 inches.

The highest average 31-day accumulation is 4.1 inches on March 29.

Snowfall

As 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 spring in Cape Cod is rapidly decreasing, starting the season at 3.9 inches, when it rarely exceeds 9.7 inches or falls below 0.1 inches, and ending the season at -0.0 inches, when it rarely exceeds 0.0 inches or falls below -0.0 inches.

Over the course of the spring in Cape Cod, the length of the day is very rapidly increasing. From the start to the end of the season, the length of the day increases by 3 hours, 42 minutes, implying an average daily increase of 2 minutes, 27 seconds, and weekly increase of 17 minutes, 7 seconds.

The shortest day of the spring is March 1, with 11 hours, 17 minutes of daylight and the longest day is May 31, with 15 hours, 0 minutes of daylight.

The latest sunrise of the spring in Cape Cod is 7:00 AM on March 10 and the earliest sunrise is 1 hour, 51 minutes earlier at 5:09 AM on May 31.

The earliest sunset is 5:32 PM on March 1 and the latest sunset is 2 hours, 37 minutes later at 8:08 PM on May 31.

Daylight saving time (DST) ends at 3:00 AM on March 10, 2024, shifting sunrise and sunset to be an hour earlier.

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.

The figure below presents a compact representation of key lunar data for the spring 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.

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 chance that a given day will be muggy in Cape Cod is essentially constant during the spring, remaining within 1% of 1% throughout.

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.

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 Cape Cod is very rapidly decreasing during the spring, decreasing from 15.9 miles per hour to 10.7 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 spring is predominantly out of the west from March 1 to March 13, the north from March 13 to April 15, and the south from April 15 to May 31.

Cape 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 increasing during the spring, rising by 14°F, from 39°F to 53°F, over the course of the season.

The lowest average surface water temperature during the spring is 39°F on March 4.

Definitions 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 spring in Cape Cod, the chance that a given day is within the growing season is very rapidly increasing rising from 0% to 100% 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 increasing during the spring, increasing by 220°F, from 3°F to 223°F, over the course of the season.

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 in Cape Cod is very rapidly increasing during the spring, rising by 3.3 kWh, from 3.3 kWh to 6.5 kWh, over the course of the season.

For 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%).