Gainesville weather in September

In September, Gainesville sees average daytime highs of 86°F and overnight lows near 67°F, with 3.3 in of rain across 6.8 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 90°F in the first days to 82°F by the end. The sky is clear or mostly clear about 54% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Gainesville's 3rd-clearest and 11th-windiest month. For the whole year in context, see Gainesville's year-round climate.

Daytime high
86°
4th warmest
Overnight low
67°
9th coldest
Rainfall
3.3 in
6.8 wet days
Daylight
12 h 12 min
6:17 AM – 6:29 PM
Cloud cover
40%
3rd clearest
Wind
6 mph
11th windiest
Solar energy
5.13 kWh/m²
Travel score
5.7
out of 10

Gainesville is city in Texas, United States.

Density
330/km²
people per km²

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 90°F in the first days to 82°F by the end.

A typical September day in Gainesville reaches about 86°F in the afternoon and slips back to 67°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 77°F and 94°F. Set against its neighbours, September runs about 7°F cooler than August and about 10°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
19072
29071
39071
48971
58970
68970
78870
88869
98869
108769
118769
128768
138668
148668
158667
168567
178567
188566
198566
208465
218465
228465
238364
248364
258363
268363
278262
288262
298262
308161

How September really feels in Gainesville

Once humidity and wind are folded in, September averages 7 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
7
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Gainesville weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan54° / 35°2.35.80.8103.6
Feb58° / 39°2.56.80.710.84.7
Mar66° / 46°3.78.30.311.76.4
Apr73° / 54°3.98.1012.87.2
May81° / 63°5.311.4013.76.2
Jun89° / 71°3.78.3014.24.5
Jul93° / 75°2.05.90143.4
Aug93° / 74°2.06.2013.23.5
Sep86° / 67°3.36.8012.25.7
Oct75° / 55°4.07.8011.27.5
Nov64° / 45°2.76.40.210.36.4
Dec55° / 37°2.76.10.59.83.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 54% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 29%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17327
27228
37228
47129
57129
66931
76931
86832
96832
106832
116733
126733
136733
146733
156832
166832
176832
186931
196931
207129
217129
227228
237327
247426
257426
267525
277525
287525
297426
307426

Chance of precipitation in September

Any precipitation

Gainesville gets around 3.3 in of rain over 6.8 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 23% and peaks near 26% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
123
223
324
424
524
625
725
825
926
1026
1126
1226
1326
1426
1526
1626
1726
1825
1925
2024
2123
2222
2321
2420
2519
2618
2718
2818
2918
3019

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 33% of days. Sticky, muggy-or-worse air turns up on roughly 47% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1410254220
2511254119
3611244019
4612243918
5712243918
6812233818
7913233817
81013223817
91113223817
101213213817
111213203817
121313203816
131413193716
141513193716
151613193715
161713193615
171913183614
182013183513
192214193313
202314193212
212514193111
222714192910
23291519289
24311519269
25331520258
26341520237
27361520226
28381621206
29391621195
30401621185

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 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 60 minutes over September. Sunrise moves from 6:06 AM to 6:27 AM, and sunset from 6:50 PM to 6:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.76:066:50
212.76:076:49
312.76:086:47
412.66:086:46
512.66:096:45
612.66:106:43
712.56:106:42
812.56:116:40
912.56:126:39
1012.46:136:38
1112.46:136:36
1212.36:146:35
1312.36:156:33
1412.36:156:32
1512.26:166:30
1612.26:176:29
1712.26:176:28
1812.16:186:26
1912.16:196:25
2012.16:196:23
2112.06:206:22
2212.06:216:20
2312.06:226:19
2411.96:226:18
2511.96:236:16
2611.86:246:15
2711.86:246:13
2811.86:256:12
2911.76:266:10
3011.76:276:09

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.13 kWh/m².

For context, solar energy here swings from a low near 2.57 kWh/m² to a high of 6.86 kWh/m² in July across the year — September's 5.13 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.7Bright
25.6Bright
35.6Bright
45.5Bright
55.5Bright
65.5Bright
75.4Bright
85.3Bright
95.3Bright
105.3Bright
115.2Bright
125.2Bright
135.1Bright
145.1Bright
155.1Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
274.8Bright
284.8Bright
294.8Bright
304.8Bright
Planning a trip in September

Is September a good time to visit Gainesville?

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

5.7
Sightseeing
6th-best month of the year
7.5
Beach & pool
1st-best month of the year

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

What to pack for Gainesville in September

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

In September, Gainesville sees daytime highs around 86°F and nights near 67°F. Pack light clothes. Worth having: sun protection. About 7 days see rain.

light clothessun protection

UV index in Gainesville 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 Gainesville peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highExtremeVery highHighModerateJun 23UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr9Very high
May9Very high
Jun10Extreme
Jul10Extreme
Aug10Very high
Sep7Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Gainesville 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 Gainesville is worst in July — around 17 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (November, 5 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1616 µg/m³Nov 235 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb7Good
Mar9Good
Apr9Good
May12Good
Jun14Moderate
Jul17Moderate
Aug13Moderate
Sep9Good
Oct6Good
Nov5Good
Dec5Good
Location & terrain

Where is Gainesville?

Gainesville sits at 33.6°N, 97.1°W, 751 ft above sea level, in United States. The nearest listed city is Denton, 29 mi away.

Topography around Gainesville

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

Within 2 miles, the terrain around Gainesville has only modest variations in elevation — a maximum elevation change of 161 ft around an average of 751 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 384 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 896 ft.

The land around Gainesville is covered by trees (38%) and grassland (38%) within 2 miles, grassland (57%) and trees (30%) within 10 miles, and grassland (53%) and trees (30%) within 50 miles.

2 miles
161 ft
10 miles
384 ft
50 miles
896 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Denton 29 mi · Celina 29 mi · Sherman 30 mi · Corinth 33 mi · Prosper 33 mi · Little Elm 34 mi · Denison 35 mi · The Trails of Frisco 35 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 Gainesville (33.6259°, -97.1333°, elevation 751 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. 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).