Decatur (AL) Temperature by Month
Decatur in Alabama, United States of America sees significant seasonal temperature differences, with daytime highs between 10°C (50°F) in January and 32°C (90°F) in August, averaging 22°C (72°F) annually. Explore the full monthly breakdown below.
Decatur Monthly Temperatures
The climate in Decatur is known for significant temperature differences throughout the year. At night, this contrast is just as clear, with lows ranging from 21°C (70°F) in August to -1°C (30°F) in January.
The chart below illustrates the average maximum day and minimum night temperatures in Decatur by month:
From around 4 AM to 6 AM temperatures are at their lowest; by 3 PM they've climbed to their daily peak.
The chart below shows the average temperature throughout the year:
Temperature: Decatur vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Decatur vs World: Temperature Compared
Decatur's average annual maximum temperature is 22°C (72°F). To put that in context, here's how it compares to a few well-known destinations:
Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.
Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.
San Francisco, USA averages 19°C (66°F) annually, but with little seasonal variation — summers are often cool and foggy, winters mild.
Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.
What Does the Temperature Feel Like in Decatur?
Temperature alone doesn't tell the whole story — humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.
In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.
In Decatur, January is the coolest month, with average highs of 10°C (50°F) and humidity around 72% — considered high. In August, the warmest month, temperatures average 32°C (90°F) with 73% humidity — conditions that feel high. For a full picture, see our humidity page.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Global average temperatures have risen by around 1.2°C since the pre-industrial era, and the effects are visible across many regions. Winters are milder on average, with fewer frost days and less snow in many parts of the world. Heatwaves are more frequent and more intense, and Europe's summers of 2018, 2019, and 2020 all set records.
Summers are also getting drier in some areas, while winter rainfall has increased in others. This contributies to higher river levels and more flooding. In many countries, spring arrives earlier and autumn lasts longer. It has knock-on effects for wildlife, agriculture, and local ecosystems.
For more on Decatur's weather — including monthly rainfall, sunshine hours, and humidity — visit our Decatur climate page.
