Winter Weather in Decatur Alabama, United States

Daily high temperatures are around 54°F, rarely falling below 35°F or exceeding 72°F. The lowest daily average high temperature is 50°F on January 9.

Daily low temperatures are around 36°F, rarely falling below 19°F or exceeding 54°F. The lowest daily average low temperature is 33°F on January 18.

For reference, on July 22, the hottest day of the year, temperatures in Decatur typically range from 70°F to 89°F, while on January 17, the coldest day of the year, they range from 33°F to 50°F.

The figure below shows you a compact characterization of the hourly average winter 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.

Bir el Ater, Algeria (5,166 miles away); Kafr Takhārīm, Syria (6,353 miles); and Yangzhong, China (7,872 miles) are the far-away foreign places with temperatures most similar to Decatur (view comparison).

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The winter in Decatur experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 52% throughout the season. The highest chance of overcast or mostly cloudy conditions is 56% on January 6.

The clearest day of the winter is December 1, with clear, mostly clear, or partly cloudy conditions 52% of the time.

For reference, on January 5, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 56%, while on October 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 67%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Decatur, the chance of a wet day over the course of the winter is essentially constant, remaining around 30% throughout.

For reference, the year's highest daily chance of a wet day is 42% on July 9, and its lowest chance is 22% on October 15.

Over the course of the winter in Decatur, the chance of a day with only rain remains an essentially constant 28% throughout, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 1% throughout.

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 winter in Decatur is gradually decreasing, starting the season at 5.1 inches, when it rarely exceeds 8.8 inches or falls below 2.3 inches, and ending the season at 4.7 inches, when it rarely exceeds 7.8 inches or falls below 2.1 inches.

The highest average 31-day accumulation is 5.1 inches on December 4.

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 winter in Decatur is gradually increasing, starting the season at 0.2 inches, when it rarely exceeds 0.4 inches or falls below -0.0 inches, and ending the season at 0.6 inches, when it rarely exceeds 1.6 inches or falls below -0.0 inches.

The highest average 31-day accumulation is 1.6 inches on February 2.

Over the course of the winter in Decatur, the length of the day is rapidly increasing. From the start to the end of the season, the length of the day increases by 1 hour, 25 minutes, implying an average daily increase of 57 seconds, and weekly increase of 6 minutes, 39 seconds.

The shortest day of the winter is December 21, with 9 hours, 50 minutes of daylight and the longest day is February 28, with 11 hours, 25 minutes of daylight.

The latest sunrise of the winter in Decatur is 6:55 AM on January 7 and the earliest sunrise is 37 minutes earlier at 6:18 AM on February 28.

The earliest sunset is 4:37 PM on December 4 and the latest sunset is 1 hour, 6 minutes later at 5:43 PM on February 28.

Daylight saving time is observed in Decatur during 2025, but it neither starts nor ends during the winter, so the entire season is in standard time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:35 AM and sets 14 hours, 29 minutes later, at 8:04 PM, while on December 21, the shortest day of the year, it rises at 6:51 AM and sets 9 hours, 50 minutes later, at 4:41 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 winter of 2025. 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 Decatur is essentially constant during the winter, remaining around 0% throughout.

The lowest chance of a muggy day during the winter is 0% on February 6.

For reference, on July 22, the muggiest day of the year, there are muggy conditions 89% of the time, while on January 28, 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 Decatur is gradually increasing during the winter, increasing from 6.5 miles per hour to 7.4 miles per hour over the course of the season.

For reference, on February 25, the windiest day of the year, the daily average wind speed is 7.4 miles per hour, while on July 28, the calmest day of the year, the daily average wind speed is 4.2 miles per hour.

The highest daily average wind speed during the winter is 7.4 miles per hour on February 27.

The wind direction in Decatur during the winter is predominantly out of the south from December 1 to January 18 and from February 26 to February 28 and the north from January 18 to February 26.

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 Decatur typically lasts for 7.3 months (225 days), from around March 25 to around November 4, rarely starting before March 3 or after April 13, and rarely ending before October 17 or after November 24.

The winter in Decatur is very likely fully outside of the growing season, with the chance that a given day is in the growing season reaching a low of -0% on December 25.

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 Decatur are very rapidly decreasing during the winter, decreasing by 4,796°F, from 4,921°F to 125°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 Decatur is increasing during the winter, rising by 1.3 kWh, from 2.7 kWh to 4.0 kWh, over the course of the season.

The lowest average daily incident shortwave solar energy during the winter is 2.4 kWh on December 25.

For the purposes of this report, the geographical coordinates of Decatur are 34.606 deg latitude, -86.983 deg longitude, and 558 ft elevation.

The topography within 2 miles of Decatur is essentially flat, with a maximum elevation change of 66 feet and an average elevation above sea level of 569 feet. Within 10 miles is essentially flat (341 feet). Within 50 miles contains only modest variations in elevation (1,608 feet).

The area within 2 miles of Decatur is covered by artificial surfaces (66%) and water (30%), within 10 miles by cropland (53%) and trees (18%), and within 50 miles by cropland (49%) and trees (44%).