Average Weather in Demopolis Alabama, United States

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2. United States
3. Alabama
4. Marengo County
5. Demopolis

In Demopolis, the summers are long, hot, and oppressive; the winters are short and cold; and it is wet and partly cloudy year round. Over the course of the year, the temperature typically varies from 38°F to 91°F and is rarely below 24°F or above 97°F.

The hot season lasts for 4.1 months, from May 19 to September 23, with an average daily high temperature above 84°F. The hottest day of the year is July 23, with an average high of 91°F and low of 73°F.

The cool season lasts for 2.8 months, from November 29 to February 23, with an average daily high temperature below 64°F. The coldest day of the year is January 17, with an average low of 38°F and high of 58°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.

In Demopolis, 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 Demopolis begins around July 29 and lasts for 3.9 months, ending around November 25. On October 8, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 68% of the time, and overcast or mostly cloudy 32% of the time.

The cloudier part of the year begins around November 25 and lasts for 8.1 months, ending around July 29. On January 3, the cloudiest day of the year, the sky is overcast or mostly cloudy 53% of the time, and clear, mostly clear, or partly cloudy 47% of the time.

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

The wetter season lasts 3.2 months, from May 18 to August 24, with a greater than 34% chance of a given day being a wet day. The chance of a wet day peaks at 47% on July 9.

The drier season lasts 8.8 months, from August 24 to May 18. The smallest chance of a wet day is 20% on October 8.

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 throughout the year is rain alone, with a peak probability of 47% on July 9.

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. Demopolis experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Demopolis. The most rain falls during the 31 days centered around February 16, with an average total accumulation of 5.4 inches.

The least rain falls around September 9, with and average total accumulation of 3.0 inches.

The length of the day in Demopolis varies significantly over the course of the year. In 2017, the shortest day is December 21, with 10 hours, 1 minute of daylight; the longest day is June 21, with 14 hours, 17 minutes of daylight.

The earliest sunrise is at 5:43 AM on June 12, and the latest sunrise is 1 hour, 28 minutes later at 7:11 AM on November 4. The earliest sunset is at 4:45 PM on December 4, and the latest sunset is 3 hours, 17 minutes later at 8:02 PM on June 29.

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

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.

Demopolis experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.2 months, from May 5 to October 10, during which time the comfort level is muggy, oppressive, or miserable at least 24% of the time. The muggiest day of the year is July 23, with muggy conditions 96% of the time.

The least muggy day of the year is January 29, when muggy conditions are essentially unheard of.

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 Demopolis experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 7.5 months, from October 1 to May 16, with average wind speeds of more than 2.2 miles per hour. The windiest day of the year is February 25, with an average hourly wind speed of 2.8 miles per hour.

The calmer time of year lasts for 4.5 months, from May 16 to October 1. The calmest day of the year is July 28, with an average hourly wind speed of 1.7 miles per hour.

The predominant average hourly wind direction in Demopolis varies throughout the year.

The wind is most often from the south for 5.5 months, from February 26 to August 11, with a peak percentage of 45% on May 4. The wind is most often from the east for 2.3 months, from August 11 to October 21, with a peak percentage of 41% on September 9. The wind is most often from the north for 4.2 months, from October 21 to February 26, with a peak percentage of 36% on January 1.

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 significant seasonal variation over the course of the year.

The brighter period of the year lasts for 4.6 months, from April 6 to August 26, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is May 20, with an average of 6.7 kWh.

The darker period of the year lasts for 2.6 months, from November 14 to February 3, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 24, with an average of 2.7 kWh.

For the purposes of this report, the geographical coordinates of Demopolis are 32.518 deg latitude, -87.836 deg longitude, and 82 ft elevation.

The topography within 2 miles of Demopolis contains only modest variations in elevation, with a maximum elevation change of 105 feet and an average elevation above sea level of 104 feet. Within 10 miles also contains only modest variations in elevation (312 feet). Within 50 miles contains only modest variations in elevation (653 feet).

The area within 2 miles of Demopolis is covered by artificial surfaces (43%), herbaceous vegetation (29%), and cropland (17%), within 10 miles by trees (39%) and cropland (31%), and within 50 miles by trees (62%) and herbaceous vegetation (20%).

This report illustrates the typical weather in Demopolis, 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 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Demopolis.

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

The stations contributing to this reconstruction are: Topton Air Estates Airport (29%, 69 kilometers, west); Centreville (28%, 69 kilometers, northeast); Tuscaloosa Municipal Airport (23%, 80 kilometers, north); Mac Crenshaw Memorial Airport (10%, 138 kilometers, southeast); and Middleton Field (10%, 144 kilometers, southeast).

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.