Bay City weather in September

In September, Bay City sees average daytime highs of 88°F and overnight lows near 72°F, with 4.5 in of rain across 13.1 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 90°F in the first days to 86°F by the end. The sky is clear or mostly clear about 43% 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 Bay City's 4th-clearest and 11th-windiest month. For the whole year in context, see Bay City's year-round climate.

Daytime high
88°
4th warmest
Overnight low
72°
9th coldest
Rainfall
4.5 in
13.1 wet days
Daylight
12 h 12 min
6:13 AM – 6:23 PM
Cloud cover
51%
4th clearest
Wind
6 mph
11th windiest
Solar energy
5.03 kWh/m²
Travel score
4.2
out of 10

Bay City is city in and the county seat of Matagorda County, Texas, United States.

Density
772/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 86°F by the end.

A typical September day in Bay City reaches about 88°F in the afternoon and slips back to 72°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 82°F and 93°F. Set against its neighbours, September runs about 4°F cooler than August and about 6°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
19175
29074
39074
49074
59074
69074
79074
88974
98973
108973
118973
128973
138973
148973
158872
168872
178872
188872
198871
208771
218771
228770
238770
248770
258769
268769
278669
288668
298668
308668

How September really feels in Bay City

Once humidity and wind are folded in, September averages 25 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
25
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.

Bay City 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
Jan64° / 47°3.59.310.46.0
Feb68° / 50°2.68.3116.4
Mar73° / 56°3.27.711.87.1
Apr79° / 62°3.38.512.76.9
May85° / 70°3.49.513.45.3
Jun90° / 75°4.012.213.83.8
Jul91° / 76°3.312.313.73.4
Aug92° / 76°3.612.4133.2
Sep88° / 72°4.513.112.24.2
Oct82° / 63°3.89.211.36.5
Nov73° / 55°3.58.710.67.1
Dec66° / 48°3.48.910.26.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 43% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% 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 (%)
15545
25545
35545
45545
55644
65644
75743
85743
95743
105743
115743
125743
135842
145842
155842
165941
176040
186139
196238
206337
216436
226535
236634
246832
256931
267030
277129
287129
297228
307228

Chance of precipitation in September

Any precipitation

Bay City gets around 4.5 in of rain over 13.1 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 44% and peaks near 51% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
149
249
350
450
550
651
751
850
950
1050
1149
1249
1348
1448
1547
1646
1745
1844
1943
2041
2140
2238
2337
2436
2535
2634
2732
2832
2931
3030

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 47% of days. Sticky, muggy-or-worse air turns up on roughly 84% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1114105529
2114115528
3114115627
4114115726
5115115626
6115115725
7125115724
8125115724
9125125624
10126125524
11136125523
12136135423
13136135423
14147145123
15247145023
16247154923
17248164722
18358174622
19458184421
20559184221
21669194120
227610203919
238710203818
249711203617
2510711213616
2611711213514
2712812213413
2813812213412
2914812213311
3014813213310

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 6 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
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

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 6:05 AM to 6:21 AM, and sunset from 6:42 PM to 6:06 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.66:056:42
212.66:066:41
312.66:066:39
412.56:076:38
512.56:076:37
612.56:086:36
712.46:086:35
812.46:096:33
912.46:096:32
1012.36:106:31
1112.36:106:30
1212.36:116:28
1312.36:126:27
1412.26:126:26
1512.26:136:25
1612.26:136:23
1712.16:146:22
1812.16:146:21
1912.16:156:20
2012.16:156:18
2112.06:166:17
2212.06:166:16
2312.06:176:15
2411.96:176:13
2511.96:186:12
2611.96:186:11
2711.86:196:10
2811.86:196:08
2911.86:206:07
3011.86:216:06

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.03 kWh/m².

For context, solar energy here swings from a low near 2.72 kWh/m² to a high of 6.3 kWh/m² in July across the year — September's 5.03 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.2Bright
55.2Bright
65.2Bright
75.2Bright
85.1Bright
95.1Bright
105.1Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.0Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
274.9Bright
284.9Bright
294.9Bright
304.9Bright
Planning a trip in September

Hazard calendar for Bay City

In seasonPeak

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

Bay City 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 Bay City?

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

4.2
Sightseeing
9th-best month of the year
6.2
Beach & pool
4th-best month of the year

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

What to pack for Bay City in September

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

In September, Bay City sees daytime highs around 88°F and nights near 72°F. Pack light clothes. Worth having: rain gear and sun protection. About 13 days see rain.

light clothesrain gearsun protection

Sea temperature near Bay City 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 25 mi away) is warmest in August at about 85°F and coldest in February near 62°F.

It's comfortable for a long swim from Apr 1 to Dec 5 — about 8.2 months when the water holds above 68°F.

60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan62Cool
Feb62Cool
Mar65Cool
Apr71Refreshing
May77Warm
Jun83Tropical
Jul85Tropical
Aug85Tropical
Sep84Tropical
Oct79Warm
Nov72Refreshing
Dec66Cool

UV index in Bay City 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 Bay City peaks around August 11 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 highHighModerateAug 11UV 11Dec 21UV 4
UV index (midday)Level
Jan4Moderate
Feb6High
Mar7High
Apr10Very high
May10Extreme
Jun11Extreme
Jul11Extreme
Aug11Extreme
Sep9Very high
Oct7High
Nov5High
Dec4Moderate

Air quality in Bay City 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 Bay City is worst in July — around 20 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (November, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1520 µg/m³Nov 167 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb8Good
Mar10Good
Apr11Good
May14Moderate
Jun17Moderate
Jul20Moderate
Aug15Moderate
Sep11Good
Oct7Good
Nov7Good
Dec7Good
Location & terrain

Where is Bay City?

Bay City sits at 29.0°N, 96.0°W, 52 ft above sea level, in United States. The nearest listed city is Lake Jackson, 32 mi away.

Topography around Bay City

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

Within 2 miles, the terrain around Bay City has only modest variations in elevation — a maximum elevation change of 66 ft around an average of 52 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 112 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 249 ft.

The land around Bay City is covered by trees (38%) and grassland (38%) within 2 miles, grassland (47%), cropland (28%) and trees (23%) within 10 miles, and water (28%), grassland (27%) and trees (20%) within 50 miles.

2 miles
66 ft
10 miles
112 ft
50 miles
249 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Lake Jackson 32 mi · Angleton 35 mi · Rosenberg 41 mi · New Territory 46 mi · Pecan Grove 47 mi · Sugar Land 48 mi · Fresno 50 mi · Stafford 50 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 Bay City (28.9828°, -95.9694°, elevation 52 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).