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Fall Weather in Bethany Beach Delaware, United States

Daily high temperatures decrease by 26°F, from 79°F to 53°F, rarely falling below 42°F or exceeding 86°F.

Daily low temperatures decrease by 28°F, from 67°F to 39°F, rarely falling below 28°F or exceeding 74°F.

For reference, on July 20, the hottest day of the year, temperatures in Bethany Beach typically range from 71°F to 83°F, while on January 31, the coldest day of the year, they range from 29°F to 43°F.

Average High and Low Temperature in the Fall in Bethany Beach

Average High and Low Temperature in the Fall in Bethany BeachSepOctNov20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°FSummerWinterSep 179°FSep 179°F67°F67°FNov 3053°FNov 3053°F39°F39°FOct 171°FOct 171°F58°F58°FNov 162°FNov 162°F47°F47°F
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 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.

Average Hourly Temperature in the Fall in Bethany Beach

Average Hourly Temperature in the Fall in Bethany BeachSepOctNov12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMSummerWintervery coldcoldcoolcomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.
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The fall in Bethany Beach experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 39% to 46%. The lowest chance of overcast or mostly cloudy conditions is 36% on October 11.

The clearest day of the fall is October 11, with clear, mostly clear, or partly cloudy conditions 64% of the time.

For reference, on January 5, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 51%, while on October 11, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 64%.

Cloud Cover Categories in the Fall in Bethany Beach

Cloud Cover Categories in the Fall in Bethany BeachSepOctNov0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SummerWinterJan 549%Jan 549%Sep 161%Sep 161%Nov 3054%Nov 3054%Oct 163%Oct 163%Nov 158%Nov 158%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Bethany Beach, the chance of a wet day over the course of the fall is essentially constant, remaining around 24% throughout.

For reference, the year's highest daily chance of a wet day is 39% on August 6, and its lowest chance is 21% on October 19.

Probability of Precipitation in the Fall in Bethany Beach

Probability of Precipitation in the Fall in Bethany BeachSepOctNov0%0%5%5%10%10%15%15%20%20%25%25%30%30%35%35%40%40%SummerWinterOct 1921%Oct 1921%Sep 127%Sep 127%Nov 3026%Nov 3026%Oct 125%Oct 125%Nov 123%Nov 123%rainmixed
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 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 Bethany Beach is essentially constant, remaining about 3.4 inches throughout, and rarely exceeding 6.6 inches or falling below 0.7 inches.

Average Monthly Rainfall in the Fall in Bethany Beach

Average Monthly Rainfall in the Fall in Bethany BeachSepOctNov0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 in7 in7 inSummerWinterSep 13.4 inSep 13.4 inNov 303.4 inNov 303.4 inOct 13.5 inOct 13.5 inNov 13.3 inNov 13.3 in
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 snowfall.

Over the course of the fall in Bethany Beach, 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, 18 minutes, implying an average daily decrease of 2 minutes, 12 seconds, and weekly decrease of 15 minutes, 25 seconds.

The shortest day of the fall is November 30, with 9 hours, 41 minutes of daylight and the longest day is September 1, with 12 hours, 59 minutes of daylight.

Hours of Daylight and Twilight in the Fall in Bethany Beach

Hours of Daylight and Twilight in the Fall in Bethany BeachSepOctNov0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrSummerWinterSep 2212 hr, 10 minSep 2212 hr, 10 minnightnightdaydayNov 309 hr, 41 minNov 309 hr, 41 minNov 110 hr, 32 minNov 110 hr, 32 min
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 latest sunrise of the fall in Bethany Beach is 7:28 AM on November 2 and the earliest sunrise is 59 minutes earlier at 6:29 AM on November 3.

The latest sunset is 7:29 PM on September 1 and the earliest sunset is 2 hours, 50 minutes earlier at 4:39 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 5:36 AM and sets 14 hours, 52 minutes later, at 8:27 PM, while on December 21, the shortest day of the year, it rises at 7:14 AM and sets 9 hours, 28 minutes later, at 4:42 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in the Fall in Bethany Beach

Sunrise & Sunset with Twilight and Daylight Saving Time in the Fall in Bethany BeachSepOctNov12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMSummerWinter6:29 AM6:29 AMNov 34:57 PMNov 34:57 PM6:30 AM6:30 AMSep 17:29 PMSep 17:29 PM6:58 AM6:58 AMNov 304:39 PMNov 304:39 PM6:56 AM6:56 AMOct 16:42 PMOct 16:42 PMDSTNov 3DSTNov 3SolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day in the fall. 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.

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.

Solar Elevation and Azimuth in the Fall in Bethany Beach

Solar Elevation and Azimuth in the Fall in Bethany BeachSepOctNov12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMSummerWinter0102020304050600010203040
northeastsouthwest
Solar elevation and azimuth in the the fall of 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The 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.

Moon Rise, Set & Phases in the Fall in Bethany Beach

Moon Rise, Set & Phases in the Fall in Bethany BeachSepOctNov12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMSummerWinterAug 47:14 AMAug 47:14 AMAug 192:26 PMAug 192:26 PMSep 29:56 PMSep 29:56 PMSep 1710:35 PMSep 1710:35 PMOct 22:50 PMOct 22:50 PMOct 177:27 AMOct 177:27 AMNov 18:48 AMNov 18:48 AMNov 154:29 PMNov 154:29 PMDec 11:22 AMDec 11:22 AMDec 154:02 AMDec 154:02 AMDec 305:28 PMDec 305:28 PM8:38 PM8:38 PM8:06 PM8:06 PM7:08 AM7:08 AM7:31 PM7:31 PM7:00 PM7:00 PM7:13 AM7:13 AM6:38 PM6:38 PM5:51 PM5:51 PM7:18 AM7:18 AM7:34 AM7:34 AM5:52 PM5:52 PM4:23 PM4:23 PM7:45 AM7:45 AM7:35 AM7:35 AM7:45 AM7:45 AM7:23 AM7:23 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

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 Bethany Beach is very rapidly decreasing during the fall, falling from 54% to 0% over the course of the season.

For reference, on August 1, the muggiest day of the year, there are muggy conditions 78% of the time, while on January 9, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in the Fall in Bethany Beach

Humidity Comfort Levels in the Fall in Bethany BeachSepOctNov0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%SummerWinterSep 154%Sep 154%Nov 300%Nov 300%Oct 121%Oct 121%Nov 13%Nov 13%oppressiveoppressivemuggymuggyhumidhumiddrydrymiserablemiserablecomfortablecomfortable
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

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 Bethany Beach is very rapidly increasing during the fall, increasing from 10.2 miles per hour to 14.5 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 15.0 miles per hour, while on July 25, the calmest day of the year, the daily average wind speed is 9.1 miles per hour.

Average Wind Speed in the Fall in Bethany Beach

Average Wind Speed in the Fall in Bethany BeachSepOctNov0 mph0 mph5 mph5 mph10 mph10 mph15 mph15 mph20 mph20 mphSummerWinterSep 110.2 mphSep 110.2 mphNov 3014.5 mphNov 3014.5 mphOct 112.1 mphOct 112.1 mphNov 113.8 mphNov 113.8 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The wind direction in Bethany Beach during the fall is predominantly out of the south from September 1 to October 8, the north from October 8 to November 14, and the west from November 14 to November 30.

Wind Direction in the Fall in Bethany Beach

Wind Direction in the Fall in Bethany BeachSNWSepOctNov0%100%20%80%40%60%60%40%80%20%100%0%SummerWinterwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Bethany Beach 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 Bethany Beach is very rapidly decreasing during the fall, falling by 21°F, from 74°F to 52°F, over the course of the season.

Average Water Temperature in the Fall in Bethany Beach

Average Water Temperature in the Fall in Bethany BeachSepOctNov40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F80°F80°FSummerWinterSep 174°FSep 174°FNov 3052°FNov 3052°FOct 169°FOct 169°FNov 160°FNov 160°F
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

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 Bethany Beach typically lasts for 7.7 months (235 days), from around March 26 to around November 16, rarely starting before March 9 or after April 11, and rarely ending before October 31 or after December 3.

During the fall in Bethany Beach, the chance that a given day is within the growing season is very rapidly decreasing falling from 100% to 15% over the course of the season.

Time Spent in Various Temperature Bands and the Growing Season in the Fall in Bethany Beach

Time Spent in Various Temperature Bands and the Growing Season in the Fall in Bethany Beachgrowing seasonSepOctNov0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SummerWinter100%Sep 1100%Sep 1Nov 3015%Nov 3015%100%Oct 1100%Oct 188%Nov 188%Nov 1freezingvery coldcoldcoolcomfortablewarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing 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 Bethany Beach are very rapidly increasing during the fall, increasing by 992°F, from 2,885°F to 3,877°F, over the course of the season.

Growing Degree Days in the Fall in Bethany Beach

Growing Degree Days in the Fall in Bethany BeachSepOctNov2,800°F2,800°F3,000°F3,000°F3,200°F3,200°F3,400°F3,400°F3,600°F3,600°F3,800°F3,800°F4,000°F4,000°FSummerWinterSep 12,885°FSep 12,885°FNov 303,877°FNov 303,877°FOct 13,454°FOct 13,454°FNov 13,766°FNov 13,766°F
The average growing degree days accumulated over the course of the fall, with 25th to 75th and 10th to 90th percentile bands.

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 Bethany Beach is very rapidly decreasing during the fall, falling by 3.3 kWh, from 5.6 kWh to 2.3 kWh, over the course of the season.

Average Daily Incident Shortwave Solar Energy in the Fall in Bethany Beach

Average Daily Incident Shortwave Solar Energy in the Fall in Bethany BeachSepOctNov0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhSummerWinterSep 15.6 kWhSep 15.6 kWhNov 302.3 kWhNov 302.3 kWhOct 14.5 kWhOct 14.5 kWhNov 13.2 kWhNov 13.2 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.

For the purposes of this report, the geographical coordinates of Bethany Beach are 38.540 deg latitude, -75.055 deg longitude, and 7 ft elevation.

The topography within 2 miles of Bethany Beach is essentially flat, with a maximum elevation change of 13 feet and an average elevation above sea level of 2 feet. Within 10 miles is also essentially flat (39 feet). Within 50 miles is essentially flat (128 feet).

The area within 2 miles of Bethany Beach is covered by water (48%), artificial surfaces (31%), and herbaceous vegetation (10%), within 10 miles by water (66%) and cropland (16%), and within 50 miles by water (61%) and cropland (19%).

This report illustrates the typical weather in Bethany Beach, 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Bethany Beach.

For each station, the records are corrected for the elevation difference between that station and Bethany Beach 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 Bethany Beach is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Bethany Beach and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of Bethany Beach and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The 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.

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