Galveston weather in September

In September, Galveston sees average daytime highs of 83°F and overnight lows near 78°F, with 6.3 in of rain across 12.5 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 84°F in the first days to 81°F by the end. The sky is clear or mostly clear about 51% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 36 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Galveston's 4th-clearest and 10th-windiest month. For the whole year in context, see Galveston's year-round climate.

Daytime high
83°
4th warmest
Overnight low
78°
9th coldest
Rainfall
6.3 in
12.5 wet days
Daylight
12 h 12 min
6:08 AM – 6:19 PM
Cloud cover
46%
4th clearest
Wind
11 mph
10th windiest
Solar energy
5.12 kWh/m²
Travel score
5.8
out of 10

Galveston is city in and county seat of Galveston County, Texas, United States; port and coastal city.

Density
93/km²
people per km²
Founded
1785

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 84°F in the first days to 81°F by the end.

A typical September day in Galveston reaches about 83°F in the afternoon and slips back to 78°F overnight — a 5°F spread between the day's warmth and the night's chill. On most days the high lands between 80°F and 85°F. Set against its neighbours, September runs about 2°F cooler than August and about 6°F warmer than October.

70°80°90°151015202530
Avg high (°F)Avg low (°F)
18480
28480
38480
48480
58480
68480
78479
88479
98379
108379
118379
128379
138379
148378
158378
168378
178378
188278
198278
208277
218277
228277
238277
248277
258176
268176
278176
288176
298175
308075

How September really feels in Galveston

Once humidity and wind are folded in, September averages 13 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
13
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.

Galveston weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan60° / 53°4.810.410.34.7
Feb61° / 55°3.58.710.95.2
Mar66° / 61°3.47.911.86.4
Apr72° / 67°3.57.212.77.3
May78° / 74°3.07.613.47.4
Jun83° / 79°4.310.713.86.1
Jul84° / 81°3.711.613.75.4
Aug85° / 81°4.513.113.15.0
Sep83° / 78°6.312.512.25.8
Oct77° / 71°4.78.611.37.4
Nov69° / 62°4.48.210.56.8
Dec62° / 55°4.510.110.25.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 51% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 12% of September, with mostly cloudy or overcast conditions the remaining 37%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15842
25842
35842
45842
55842
65842
75842
85842
95842
105842
115941
125941
135941
145941
156040
166139
176238
186238
196337
206535
216634
226733
236931
247030
257030
267228
277327
287327
297327
307426

Chance of precipitation in September

Any precipitation

Galveston gets around 6.3 in of rain over 12.5 wet days in September, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 41% and peaks near 50% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
150
250
350
450
549
649
748
848
947
1047
1146
1245
1345
1444
1544
1643
1742
1841
1940
2038
2137
2236
2335
2434
2533
2632
2731
2830
2929
3029

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 39% of days. Sticky, muggy-or-worse air turns up on roughly 89% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
101263457
201263556
301273654
401273753
501373851
601373950
701383949
801384048
901384047
1002494045
1102494145
1202494143
13024104142
14025104241
15025114240
16125124239
17126124237
18136134136
19146144134
20147144133
21257154031
22268164029
23278163927
24288173926
25389183824
26399183822
2741010183821
2841010183819
2941111183718
3051111183717

Wind in September

Winds average 11 mph in September.

Across September, daily wind ranges from about 10 mph on the calmest days to 11 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
110light breeze
210light breeze
310light breeze
410light breeze
510light breeze
610light breeze
710light breeze
810light breeze
910light breeze
1010light breeze
1111light breeze
1211light breeze
1311light breeze
1411light breeze
1511light breeze
1611light breeze
1711light breeze
1811light breeze
1911light breeze
2011light breeze
2111light breeze
2211light breeze
2311light breeze
2411light breeze
2511light breeze
2611light breeze
2711light breeze
2811light breeze
2911light breeze
3011light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 36 min at the start of September to 11 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 48 minutes over September. Sunrise moves from 6:00 AM to 6:16 AM, and sunset from 6:37 PM to 6:01 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.66:006:37
212.66:016:36
312.66:016:35
412.56:026:34
512.56:026:33
612.56:036:31
712.46:046:30
812.46:046:29
912.46:056:28
1012.46:056:26
1112.36:066:25
1212.36:066:24
1312.36:076:23
1412.26:076:21
1512.26:086:20
1612.26:086:19
1712.16:096:17
1812.16:096:16
1912.16:106:15
2012.16:106:14
2112.06:116:12
2212.06:126:11
2312.06:126:10
2411.96:136:09
2511.96:136:07
2611.96:146:06
2711.86:146:05
2811.86:156:04
2911.86:156:02
3011.86:166:01

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.12 kWh/m².

For context, solar energy here swings from a low near 2.75 kWh/m² to a high of 6.42 kWh/m² in July across the year — September's 5.12 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.4Bright
45.3Bright
55.3Bright
65.3Bright
75.3Bright
85.2Bright
95.2Bright
105.2Bright
115.2Bright
125.1Bright
135.1Bright
145.1Bright
155.1Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
265.0Bright
275.0Bright
285.0Bright
294.9Bright
304.9Bright
Planning a trip in September

Hazard calendar for Galveston

In seasonPeak

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

Galveston 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 Galveston?

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

5.8
Sightseeing
7th-best month of the year
6.6
Beach & pool
4th-best month of the year

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

What to pack for Galveston in September

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

In September, Galveston sees daytime highs around 83°F and nights near 78°F. Pack light clothes. Worth having: rain gear and sun protection. About 13 days see rain.

light clothesrain gearsun protection

Sea temperature near Galveston in September

The nearest coast averages about 84°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 12 mi away) is warmest in August at about 86°F and coldest in January near 58°F.

It's comfortable for a long swim from Apr 4 to Nov 21 — about 7.6 months when the water holds above 68°F.

60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan58Bracing
Feb59Cool
Mar64Cool
Apr71Refreshing
May78Warm
Jun83Tropical
Jul85Tropical
Aug86Tropical
Sep84Tropical
Oct78Warm
Nov69Refreshing
Dec62Cool

UV index in Galveston in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Galveston peaks around July 18 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 4 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 18UV 11Dec 21UV 4
UV index (midday)Level
Jan4Moderate
Feb6High
Mar7High
Apr10Extreme
May10Extreme
Jun11Extreme
Jul11Extreme
Aug11Extreme
Sep9Very high
Oct6High
Nov5High
Dec4Moderate

Air quality in Galveston 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 Galveston is worst in July — around 19 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (December, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1519 µg/m³Dec 176 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb7Good
Mar8Good
Apr9Good
May12Good
Jun16Moderate
Jul19Moderate
Aug13Moderate
Sep10Good
Oct6Good
Nov6Good
Dec6Good
Location & terrain

Where is Galveston?

Galveston sits at 29.3°N, 94.8°W, 7 ft above sea level, in United States. The nearest listed city is Texas City, 8.7 mi away.

Topography around Galveston

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

Within 2 miles, the terrain around Galveston has only modest variations in elevation — a maximum elevation change of 43 ft around an average of 7 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 62 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 236 ft.

The land around Galveston is covered by artificial surfaces (41%) and water (32%) within 2 miles, water (80%) within 10 miles, and water (45%) within 50 miles.

2 miles
43 ft
10 miles
62 ft
50 miles
236 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Texas City 8.7 mi · La Marque 11 mi · Dickinson 19 mi · League City 23 mi · Alvin 28 mi · La Porte 29 mi · Friendswood 29 mi · Baytown 32 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 Galveston (29.3013°, -94.7977°, elevation 7 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). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).