Decatur weather in September

In September, Decatur sees average daytime highs of 83°F and overnight lows near 65°F, with 3.5 in of rain across 7.7 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 86°F in the first days to 79°F by the end. The sky is clear or mostly clear about 42% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Decatur's 2nd-clearest and 9th-windiest month. For the whole year in context, see Decatur's year-round climate.

Daytime high
83°
4th warmest
Overnight low
65°
9th coldest
Rainfall
3.5 in
7.7 wet days
Daylight
12 h 12 min
5:36 AM – 5:49 PM
Cloud cover
49%
2nd clearest
Wind
5 mph
9th windiest
Solar energy
4.84 kWh/m²
Travel score
6.3
out of 10

Decatur is city in Morgan and Limestone counties, Alabama, United States.

Density
354/km²
people per km²
Founded
1821

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 86°F in the first days to 79°F by the end.

A typical September day in Decatur reaches about 83°F in the afternoon and slips back to 65°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 90°F. Set against its neighbours, September runs about 5°F cooler than August and about 10°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18669
28669
38669
48668
58568
68568
78567
88567
98567
108467
118466
128466
138466
148365
158365
168365
178364
188264
198264
208263
218163
228163
238162
248062
258061
268061
277960
287960
297860
307859

How September really feels in Decatur

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Decatur weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan51° / 35°4.99.90.69.92.4
Feb55° / 38°4.710.40.610.73.4
Mar63° / 45°5.511.40.211.75.4
Apr71° / 53°5.010.1012.86.6
May79° / 62°4.210.9013.86.5
Jun86° / 69°4.312.6014.34.8
Jul88° / 72°4.213.1014.14.2
Aug88° / 71°3.111.5013.34.4
Sep83° / 65°3.57.7012.26.3
Oct73° / 53°3.47.4011.17.3
Nov61° / 43°4.08.50.110.25.4
Dec53° / 37°5.210.70.39.73.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 39%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15941
26139
36139
46139
56238
66238
76238
86337
96337
106238
116238
126238
136238
146238
156139
166040
176040
185941
195941
205941
215941
226040
236040
246139
256139
266238
276337
286436
296436
306535

Chance of precipitation in September

Any precipitation

Decatur gets around 3.5 in of rain over 7.7 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 26% and peaks near 30% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
130
229
329
428
528
627
727
826
926
1025
1125
1225
1326
1426
1526
1627
1727
1827
1927
2027
2127
2226
2326
2425
2524
2624
2723
2823
2922
3022

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the muggy band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 44% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
127194130
238204128
338214027
449224025
5410233924
6511243822
7511253721
8612263619
9713273518
10714273417
11815283317
12915283216
131016283116
141117283015
151117282915
161218282815
171318282714
181418282614
191619282513
201719272413
211919272412
222119272311
232319262210
24241926219
25262025218
26282024207
27302024207
28322123196
29332122195
30352122184

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 5:25 AM to 5:46 AM, and sunset from 6:10 PM to 5:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:256:10
212.75:266:09
312.75:266:08
412.75:276:06
512.65:286:05
612.65:296:03
712.55:296:02
812.55:306:00
912.55:315:59
1012.45:315:58
1112.45:325:56
1212.45:335:55
1312.35:345:53
1412.35:345:52
1512.35:355:50
1612.25:365:49
1712.25:375:47
1812.15:375:46
1912.15:385:44
2012.15:395:43
2112.05:405:41
2212.05:405:40
2312.05:415:38
2411.95:425:37
2511.95:435:35
2611.85:435:34
2711.85:445:32
2811.85:455:31
2911.75:465:30
3011.75:465:28

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.84 kWh/m².

For context, solar energy here swings from a low near 2.2 kWh/m² to a high of 6.2 kWh/m² in June across the year — September's 4.84 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.2Bright
35.2Bright
45.2Bright
55.2Bright
65.1Bright
75.1Bright
85.1Bright
95.1Bright
105.0Bright
115.0Bright
125.0Bright
134.9Bright
144.9Bright
154.9Bright
164.8Bright
174.8Bright
184.8Bright
194.7Bright
204.7Bright
214.7Bright
224.6Bright
234.6Bright
244.6Bright
254.5Bright
264.5Bright
274.5Bright
284.5Bright
294.4Bright
304.4Bright
Planning a trip in September

Hazard calendar for Decatur

In seasonPeak

In September, Decatur sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Decatur sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Decatur?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.3
Sightseeing
4th-best month of the year
7.2
Beach & pool
1st-best month of the year

September is a reasonable time to visit Decatur for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Decatur in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Decatur sees daytime highs around 83°F and nights near 65°F. Pack light clothes. Worth having: sun protection. About 8 days see rain.

light clothessun protection

UV index in Decatur in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Decatur peaks around July 12 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highHighModerateJul 12UV 10Dec 19UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May8Very high
Jun10Very high
Jul10Extreme
Aug9Very high
Sep7Very high
Oct5High
Nov4Moderate
Dec2Moderate

Air quality in Decatur in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Decatur is worst in July — around 19 µg/m³ PM2.5 (moderate), about 3.3× the cleanest month (January, 6 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1719 µg/m³Jan 116 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb8Good
Mar10Good
Apr10Good
May13Moderate
Jun16Moderate
Jul19Moderate
Aug16Moderate
Sep11Good
Oct8Good
Nov7Good
Dec6Good
Location & terrain

Where is Decatur?

Decatur sits at 34.6°N, 87.0°W, 561 ft above sea level, in United States. The nearest listed city is Athens, 14 mi away.

Topography around Decatur

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Decatur.

Within 2 miles, the terrain around Decatur has only modest variations in elevation — a maximum elevation change of 138 ft around an average of 571 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 505 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,621 ft.

The land around Decatur is covered by trees (31%), water (30%) and artificial surfaces (22%) within 2 miles, trees (43%) and cropland (23%) within 10 miles, and trees (62%) and grassland (23%) within 50 miles.

2 miles
138 ft
10 miles
505 ft
50 miles
1,621 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Athens 14 mi · Madison 15 mi · Huntsville 24 mi · Cullman 31 mi · East Florence 40 mi · Florence 42 mi · Albertville 50 mi · Dixiana 63 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Decatur (34.6059°, -86.9833°, elevation 561 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).