Long Thành weather in September

In September, Long Thành sees average daytime highs of 31°C and overnight lows near 25°C, with 317 mm of rain across 28.6 wet days and about 12.1 hours of daylight. It is the 7th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 12 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Long Thành's 12th-clearest and 7th-windiest month. For the whole year in context, see Long Thành's year-round climate.

Daytime high
31°
7th warmest
Overnight low
25°
6th coldest
Rainfall
317 mm
28.6 wet days
Daylight
12 h 06 min
5:45 AM – 5:48 PM
Cloud cover
89%
12th clearest
Wind
8 km/h
7th windiest
Solar energy
4.7 kWh/m²
Travel score
2.4
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°C through the month.

A typical September day in Long Thành reaches about 31°C in the afternoon and slips back to 25°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 32°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13125
23125
33125
43125
53125
63125
73125
83125
93125
103125
113125
123125
133125
143125
153125
163125
173125
183125
193125
203125
213125
223125
233125
243125
253125
263125
273125
283125
293125
303125

How September really feels in Long Thành

Once humidity and wind are folded in, September averages 30 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
30
heat index over the day's high
Days feeling ≤ C
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.

Long Thành weather by month

How September compares with the rest of the year at a glance. September is the 7th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 23°264.111.45.2
Feb32° / 24°10211.64.9
Mar33° / 25°244.611.94.0
Apr34° / 26°6811.912.23.1
May33° / 26°20724.412.52.3
Jun31° / 26°26827.612.62.4
Jul31° / 25°28529.312.62.5
Aug31° / 25°29429.312.42.5
Sep31° / 25°31728.612.12.4
Oct31° / 25°27227.511.82.7
Nov31° / 24°14417.811.53.7
Dec30° / 23°7210.511.44.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% of the time in September, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 5% of September, with mostly cloudy or overcast conditions the remaining 94%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1694
2694
3694
4694
5694
6694
7694
8694
9694
10694
11694
12694
13694
14595
15595
16595
17595
18694
19694
20694
21694
22694
23694
24694
25793
26793
27793
28793
29793
30892

Chance of precipitation in September

Any precipitation

Long Thành gets around 317 mm of rain over 28.6 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 95% and peaks near 97% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
194
294
394
494
595
695
795
895
995
1095
1195
1295
1395
1495
1595
1695
1795
1895
1995
2095
2196
2296
2396
2496
2596
2696
2796
2896
2996
3097

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 93% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
1694
2694
3694
4694
5694
6694
7793
8793
9793
10793
11793
12892
13892
14892
15892
16892
17892
18892
19892
20892
21892
22892
23892
24892
25892
26892
27892
28892
29892
30892

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 12 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over September. Sunrise moves from 5:46 AM to 5:44 AM, and sunset from 5:58 PM to 5:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:465:58
212.25:465:58
312.25:465:57
412.25:455:56
512.25:455:56
612.25:455:55
712.25:455:54
812.15:455:54
912.15:455:53
1012.15:455:52
1112.15:455:52
1212.15:455:51
1312.15:455:50
1412.15:455:50
1512.15:455:49
1612.15:455:48
1712.05:455:48
1812.05:455:47
1912.05:455:46
2012.05:445:46
2112.05:445:45
2212.05:445:44
2312.05:445:44
2412.05:445:43
2512.05:445:42
2612.05:445:42
2711.95:445:41
2811.95:445:40
2911.95:445:40
3011.95:445:39

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.7 kWh/m².

For context, solar energy here swings from a low near 4.53 kWh/m² to a high of 6.25 kWh/m² in March across the year — September's 4.7 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.9Bright
54.9Bright
64.9Bright
74.8Bright
84.8Bright
94.8Bright
104.7Bright
114.7Bright
124.7Bright
134.7Bright
144.6Bright
154.6Bright
164.6Bright
174.6Bright
184.6Bright
194.6Bright
204.6Bright
214.6Bright
224.6Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.6Bright
284.5Bright
294.5Bright
304.5Bright
Planning a trip in September

Hazard calendar for Long Thành

In seasonPeak

In September, Long Thành sits inside its pacific typhoon and rainy season season. The full year is below, with each hazard's peak months called out.

Long Thành sits in the Pacific typhoon belt; the season peaks July–October.

Long Thành's rainy season runs May–November, when most of the year's rain falls.

Pacific typhoon
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Long Thành?

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

2.4
Sightseeing
10th-best month of the year
3.6
Beach & pool
12th-best month of the year

September is a weaker month for outdoor sightseeing in Long Thành.

What to pack for Long Thành in September

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

In September, Long Thành sees daytime highs around 31°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 29 days see rain.

light clothesrain gearsun protection

Sea temperature near Long Thành in September

The nearest coast averages about 29°C 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 47 km away) is warmest in May at about 30°C and coldest in January near 26°C.

The water stays above 20°C all year — warm enough for a swim any month.

24°26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan26Warm
Feb26Warm
Mar27Warm
Apr29Tropical
May30Tropical
Jun30Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov28Tropical
Dec27Warm

UV index in Long Thành in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Long Thành peaks around March 23 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 15 at about 8 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highMar 23UV 13Nov 15UV 8
UV index (midday)Level
Jan10Very high
Feb11Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun11Extreme
Jul11Extreme
Aug12Extreme
Sep12Extreme
Oct9Very high
Nov8Very high
Dec9Very high

Air quality in Long Thành 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 Long Thành is worst in October — around 34 µg/m³ PM2.5 (moderate), about 1.6× the cleanest month (March, 21 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateOct 1434 µg/m³Mar 1921 µg/m³
PM2.5 (µg/m³)Level
Jan26Moderate
Feb21Moderate
Mar21Moderate
Apr21Moderate
May25Moderate
Jun30Moderate
Jul29Moderate
Aug29Moderate
Sep33Moderate
Oct34Moderate
Nov31Moderate
Dec34Moderate
Location & terrain

Where is Long Thành?

Long Thành sits at 10.8°N, 107.0°E, 19 m above sea level, in Vietnam. The nearest listed city is Trảng Bom, 19 km away.

Topography around Long Thành

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Long Thành.

Within 3 km, the terrain around Long Thành has only modest variations in elevation — a maximum elevation change of 45 m around an average of 13 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 141 m; within 80 km, large variations in elevation — a maximum elevation change of 918 m.

The land around Long Thành is covered by trees (44%) and artificial surfaces (32%) within 3 km, trees (44%) within 16 km, and trees (49%) and water (20%) within 80 km.

3 km
45 m
16 km
141 m
80 km
918 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Trảng Bom 19 km · Thủ Đức 21 km · Phú Mỹ 21 km · Biên Hòa 22 km · Xóm Mỹ Xuân 23 km · Dĩ An 24 km · Nhà Bè 25 km · Bình Thạnh 27 km

Vietnam travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B / C / F
220 V · 50 Hz
Prices
≈ 29% of US
price level, 2025
GDP per capita
$5,066
2025
Happiness
6.4 / 10
World Happiness, 2025
Safe drinking water
59%
of population, 2024
Homicide rate
1.5
per 100k, 2011
Road deaths
30.6
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Moderate
EF EPI 500
Religion
none 86%Catholic 6%Buddhist 6%Protestant 1%

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 Long Thành (10.7891°, 106.9503°, elevation 19 m), 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).