Bangkok Riverside weather in September

In September, Bangkok Riverside sees average daytime highs of 33°C and overnight lows near 26°C, with 237 mm of rain across 25.3 wet days and about 12.1 hours of daylight. It is the 8th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 33°C through the month. The sky is clear or mostly clear about 2% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 18 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Bangkok Riverside's 9th-clearest and 10th-windiest month. For the whole year in context, see Bangkok Riverside's year-round climate.

Daytime high
33°
8th warmest
Overnight low
26°
6th coldest
Rainfall
237 mm
25.3 wet days
Daylight
12 h 06 min
6:10 AM – 6:15 PM
Cloud cover
86%
9th clearest
Wind
8 km/h
10th windiest
Solar energy
4.64 kWh/m²
Travel score
2.2
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 33°C through the month.

A typical September day in Bangkok Riverside reaches about 33°C in the afternoon and slips back to 26°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 34°C. Set against its neighbours, September runs on par with August and on par with October.

25°28°30°33°35°151015202530
Avg high (°C)Avg low (°C)
13327
23326
33326
43326
53326
63326
73326
83326
93326
103326
113326
123326
133326
143326
153326
163326
173226
183226
193226
203226
213226
223226
233226
243226
253226
263226
273226
283226
293226
303226

How September really feels in Bangkok Riverside

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
30 feel dangerously hot (≥ 39°C)
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.

Bangkok Riverside weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 22°152.911.35.0
Feb33° / 24°132.811.54.3
Mar34° / 26°416.311.93.3
Apr35° / 28°6810.412.32.3
May35° / 28°13020.112.61.9
Jun34° / 27°12721.812.82.1
Jul33° / 27°13422.912.72.2
Aug33° / 27°14523.612.52.2
Sep33° / 26°23725.312.12.2
Oct32° / 26°19120.711.72.9
Nov32° / 24°426.411.44.2
Dec32° / 23°101.711.25.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 8% of September, with mostly cloudy or overcast conditions the remaining 90%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1892
2892
3793
4793
5793
6793
7793
8793
9793
10793
11793
12793
13892
14892
15892
16991
17991
18991
191090
201189
211288
221288
231387
241387
251387
261486
271486
281585
291585
301684

Chance of precipitation in September

Any precipitation

Bangkok Riverside gets around 237 mm of rain over 25.3 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 85% and peaks near 86% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
181
281
381
482
582
683
783
883
984
1084
1185
1285
1385
1486
1586
1686
1786
1886
1986
2086
2186
2286
2386
2486
2586
2686
2786
2886
2986
3086

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 86% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
11882
21882
31882
41882
51882
61981
71981
81981
91981
101981
111981
121882
131882
141783
151684
161585
171486
181387
191288
201189
211090
22991
23991
24892
25793
26793
27694
28694
29694
30694

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 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 18 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 24 minutes over September. Sunrise moves from 6:10 AM to 6:10 AM, and sunset from 6:26 PM to 6:04 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.36:106:26
212.36:106:25
312.26:106:24
412.26:106:24
512.26:106:23
612.26:106:22
712.26:106:21
812.26:106:21
912.26:106:20
1012.26:106:19
1112.16:106:18
1212.16:106:18
1312.16:106:17
1412.16:106:16
1512.16:106:15
1612.16:106:15
1712.16:106:14
1812.06:106:13
1912.06:106:12
2012.06:106:11
2112.06:106:11
2212.06:106:10
2312.06:106:09
2412.06:106:08
2512.06:106:08
2611.96:106:07
2711.96:106:06
2811.96:106:05
2911.96:106:05
3011.96:106:04

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.64 kWh/m².

For context, solar energy here swings from a low near 4.62 kWh/m² to a high of 6.24 kWh/m² in April across the year — September's 4.64 kWh/m² sits near the bottom.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.7Bright
74.7Bright
84.7Bright
94.7Bright
104.7Bright
114.7Bright
124.7Bright
134.6Bright
144.6Bright
154.6Bright
164.6Bright
174.6Bright
184.6Bright
194.5Bright
204.5Bright
214.5Bright
224.5Bright
234.5Bright
244.5Bright
254.5Bright
264.5Bright
274.5Bright
284.5Bright
294.5Bright
304.5Bright
Planning a trip in September

Hazard calendar for Bangkok Riverside

In seasonPeak

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

Bangkok Riverside sits in the Pacific typhoon belt; the season peaks July–October.

Bangkok Riverside's monsoon runs May–October, when most of the year's rain falls.

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

Is September a good time to visit Bangkok Riverside?

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

2.2
Sightseeing
8th-best month of the year
3.8
Beach & pool
12th-best month of the year

September is a weaker month for outdoor sightseeing in Bangkok Riverside.

What to pack for Bangkok Riverside in September

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

In September, Bangkok Riverside sees daytime highs around 33°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 25 days see rain.

light clothesrain gearsun protection

Sea temperature near Bangkok Riverside 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 44 km away) is warmest in May at about 31°C and coldest in January near 27°C.

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

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan27Warm
Feb28Tropical
Mar29Tropical
Apr30Tropical
May31Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec28Warm

UV index in Bangkok Riverside 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 Bangkok Riverside peaks around August 16 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 21 at about 8 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highAug 16UV 13Nov 21UV 8
UV index (midday)Level
Jan9Very high
Feb9Very high
Mar12Extreme
Apr12Extreme
May11Extreme
Jun12Extreme
Jul12Extreme
Aug13Extreme
Sep12Extreme
Oct9Very high
Nov8Very high
Dec8Very high

Air quality in Bangkok Riverside 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 Bangkok Riverside is worst in January — around 114 µg/m³ PM2.5 (unhealthy), about 2.5× the cleanest month (August, 46 µg/m³).

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

0306090120JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorUnhealthyJan 15112 µg/m³Aug 1046 µg/m³
PM2.5 (µg/m³)Level
Jan114Unhealthy
Feb97Unhealthy
Mar69Unhealthy
Apr62Unhealthy
May54Poor
Jun46Poor
Jul47Poor
Aug46Poor
Sep60Unhealthy
Oct87Unhealthy
Nov101Unhealthy
Dec102Unhealthy
Location & terrain

Where is Bangkok Riverside?

Bangkok Riverside sits at 13.8°N, 100.5°E, 7 m above sea level, in Thailand. The nearest listed city is Sathorn, 1.0 km away.

Topography around Bangkok Riverside

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

Within 3 km, the terrain around Bangkok Riverside has only modest variations in elevation — a maximum elevation change of 22 m around an average of 7 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 52 m; within 80 km, large variations in elevation — a maximum elevation change of 874 m.

The land around Bangkok Riverside is covered by artificial surfaces (84%) within 3 km, artificial surfaces (73%) and trees (20%) within 16 km, and cropland (32%) and water (27%) within 80 km.

3 km
22 m
16 km
52 m
80 km
874 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Sathorn 1.0 km · Pom Prap Sattru Phai 1.0 km · Bangkok 2.0 km · Ratchathewi 2.0 km · Samphanthawong 2.0 km · Pathum Wan 2.0 km · Phra Nakhon 2.0 km · Dusit 2.0 km

Thailand travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B / C
230 V · 50 Hz
Prices
≈ 31% of US
price level, 2025
GDP per capita
$8,057
2025
Happiness
6.3 / 10
World Happiness, 2025
Homicide rate
4.8
per 100k, 2011
Road deaths
32.2
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Very low
EF EPI 402
Religion
Buddhist 93%Muslim 5%Christian 1%other 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 Bangkok Riverside (13.7549°, 100.5172°, elevation 7 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).