PlainClimate
NOAA 1991–2020 normals 58°F annual avg Public-domain federal data

Decatur, TN Climate

Explore average temperature, rainfall, and comfort score sourced from NOAA NCEI's 1991–2020 climate normals →

58°F
Avg annual temp
73/100
Comfort score
57.6"
Annual precip
200d
Growing season

30-year climate normals from 1 weather station (1991-2020).

The climate verdict for Decatur

Decatur, Tennessee averages 58°F a year and scores 73/100 on the comfort index - good, milder than 68% of U.S. cities.

58°F
average temperature, NOAA 1991-2020 normal
73/100
comfort score, milder than 68% of U.S. cities
57.6"
annual precipitation · 3" snow
200 days
growing season, frost-free days

Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.

Avg Temperature

58°F (15°C)

Avg High

70°F

Avg Low

46°F

Annual Precip

57.6"

Annual Snow

3.3"

Comfort Score

73/100

Good

Climate Comfort Score

73/100

Good

Avg Annual Temperature

58°F

30-year mean (NOAA NCEI)

Annual Precipitation

57.6"

Plus 3.3" of snow

Comfort score vs national 100-point ceiling (Decatur) 73.0%
National median (63)

PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the Decatur area.

How Decatur compares to every U.S. city

Decatur's comfort score vs. all U.S. cities

PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals

73 Top 32% higher than 68% of 6,915 US cities

0–10: 0 US cities (0%). Below this entry. 10–20: 0 US cities (0%). Below this entry. 20–30: 58 US cities (1%). Below this entry. 30–40: 439 US cities (6%). Below this entry. 40–50: 1,302 US cities (19%). Below this entry. 50–60: 1,433 US cities (21%). Below this entry. 60–70: 1,357 US cities (20%). Below this entry. 70–80: 1,102 US cities (16%). This entry sits in this band. 80–90: 778 US cities (11%). Above this entry. 90–100: 420 US cities (6%). Above this entry. This city 0 100 every U.S. city, bucketed by value

Each bar is a band; taller bars hold more US cities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020

Warming context for Decatur

Methodology

Zooming out from Decatur's own normal, the chart below shows how the U.S. land temperature anomaly has tracked the global mean since 1900 - the most recent decade sits warmer than the 30-year mean shown here.

Warming context, U.S. vs global, with Paris reference lines Anomaly chart from 1900 to 2024. Local series shows warming of 0.11 °C per decade versus a global rate of 0.11 °C per decade (ratio 1.00). Paris Agreement thresholds at 1.5 and 2.0 °C are dashed. -1.0°C -0.5°C +0.0°C +0.5°C +1.0°C +1.5°C +2.0°C +2.5°C Paris 1.5°C Paris 2.0°C 1900192019401960198020002020
  • United States land mean (NOAA NCEI) +0.11 °C/decade
  • Global anomaly (NASA GISTEMP) +0.11 °C/decade
  • Paris Agreement thresholds 1.5°C / 2.0°C
Sources: NOAA NCEI, NASA GISTEMP. Paris thresholds per IPCC AR6 WG1.

Monthly Temperatures

Average daily high and low temperatures by month

Month Avg High Avg Low Mean
January 48°F (9°C) 28°F (-2°C) 38°F (3°C)
February 53°F (11°C) 30°F (-1°C) 41°F (5°C)
March 62°F (16°C) 36°F (2°C) 49°F (9°C)
April 71°F (22°C) 44°F (7°C) 58°F (14°C)
May 79°F (26°C) 54°F (12°C) 66°F (19°C)
June 86°F (30°C) 63°F (17°C) 74°F (24°C)
July 89°F (32°C) 67°F (19°C) 78°F (26°C)
August 89°F (32°C) 66°F (19°C) 77°F (25°C)
September 84°F (29°C) 59°F (15°C) 71°F (22°C)
October 73°F (23°C) 46°F (8°C) 59°F (15°C)
November 61°F (16°C) 35°F (1°C) 48°F (9°C)
December 51°F (11°C) 30°F (-1°C) 41°F (5°C)

Monthly Precipitation

Average monthly rainfall and snowfall

January 5.6"

Snow: 0.9"

10.6 days with precipitation

February 5.2"

Snow: 1.7"

11.4 days with precipitation

March 5.3"

Snow: 0.1"

11.1 days with precipitation

April 5.4"

10.6 days with precipitation

May 4.6"

11.6 days with precipitation

June 4.8"

11.4 days with precipitation

July 5.4"

12.5 days with precipitation

August 3.3"

9.6 days with precipitation

September 4.3"

7.1 days with precipitation

October 3.2"

7.8 days with precipitation

November 4.7"

8.5 days with precipitation

December 5.7"

Snow: 0.6"

11.0 days with precipitation

Frost Dates & Growing Season

First Fall Freeze

October 27

50% probability date

Last Spring Freeze

April 10

50% probability date

Growing Season

200 days

Heating & Cooling Degree Days

Annual totals indicate energy demand for heating and cooling

Heating Degree Days

3,840

Higher = more heating needed

Cooling Degree Days

1,450

Higher = more cooling needed

Warmest Month

July

Coldest Month

January

What Decatur's climate means for you

Decatur runs 58°F a year - peaking in July, coldest in January.

  • Gardeners get about 200 frost-free days, with the last spring freeze near April 10 - plan the planting calendar around it, not the regional average.
  • Energy bills track 3,840 heating and 1,450 cooling degree days a year, higher means the furnace or AC runs more.
  • Comparing places to live? Line this city up against nearby cities and the national rankings. See rankings

These are 30-year NOAA normals (1991–2020) - the typical year, not a forecast for any specific season.

Climate Guides

Climate Insight: Decatur, TN

Decatur, Tennessee runs an annual average of 58°F, ranging from a mean daily high of 70°F to a mean daily low of 46°F, per NOAA's 1991–2020 climate normals. July is typically the warmest month of the year, while January is the coldest. Drawn from station USC00402388, these thirty-year averages smooth out year-to-year swings into a baseline for what a typical month looks like here.

Beyond temperature, Decatur averages 57.6 inches of precipitation annually, with 3.3 inches typically falling as snow - a real factor for anyone planning to live, garden, or travel here. The frost-free season averages 200 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 10 and the first fall freeze near October 27. Turning to energy use, 3,840 heating degree days and 1,450 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Decatur scores 73/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. The monthly tables above turn that into a planning tool: expect the mildest highs and lows in the shoulder seasons, July-driven heat at the peak of summer, and January-driven cold at the depth of winter. Every number here is a thirty-year average, not a forecast, so any given year can and does run warmer, cooler, wetter, or drier than the normal.

Frequently Asked Questions

What is the average temperature in Decatur, TN?
The average annual temperature in Decatur, Tennessee is 58°F. The warmest month averages 89°F (32°C) and the coldest averages 28°F (-2°C).
How much rain does Decatur get?
Decatur receives 57.6 inches of precipitation annually, including 3.3 inches of snow. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Decatur?
Decatur has a climate comfort score of 73/100 (Good), milder than 68% of U.S. cities in the PlainClimate database.
When is the growing season in Decatur?
Decatur has approximately 200 frost-free days per year, with the last spring freeze around April 10 and the first fall freeze around October 27.
How much energy does heating and cooling require in Decatur?
Decatur has 3,840 heating degree days and 1,450 cooling degree days annually, a heating-dominated climate. See our <a href="/guides/reading-weather-data/" class="underline hover:text-brand-600">guide to reading weather data</a> for what these figures mean.
Where does this Decatur climate data come from?
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00402388 near Decatur.

Data Sources

Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00402388. For informational purposes only.

Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate Editorial

Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. This page draws directly on NOAA 1991-2020 U.S. Climate Normals data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.