Ko Chang weather in September

In September, Ko Chang sees average daytime highs of 28°C and overnight lows near 26°C, with 537 mm of rain across 28.6 wet days and about 12.1 hours of daylight. It is the 10th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°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 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 Ko Chang's 12th-clearest and 5th-windiest month. For the whole year in context, see Ko Chang's year-round climate.

Daytime high
28°
10th warmest
Overnight low
26°
4th coldest
Rainfall
537 mm
28.6 wet days
Daylight
12 h 06 min
6:03 AM – 6:07 PM
Cloud cover
90%
12th clearest
Wind
15 km/h
5th windiest
Solar energy
4.28 kWh/m²
Travel score
3.3
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 28°C through the month.

A typical September day in Ko Chang reaches about 28°C in the afternoon and slips back to 26°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 29°C. Set against its neighbours, September runs on par with August and on par with October.

24°26°28°30°32°151015202530
Avg high (°C)Avg low (°C)
12826
22826
32826
42826
52826
62826
72826
82826
92826
102826
112826
122826
132826
142826
152826
162826
172826
182826
192826
202826
212826
222826
232826
242826
252826
262826
272826
282826
292826
302826

How September really feels in Ko Chang

Once humidity and wind are folded in, September averages 15 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
15
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.

Ko Chang weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 25°286.311.47.0
Feb28° / 26°266.511.67.1
Mar28° / 27°7113.211.95.6
Apr29° / 27°11517.112.34.5
May29° / 27°44827.912.53.1
Jun29° / 27°59528.612.73.0
Jul28° / 26°61229.912.63.0
Aug28° / 26°54729.412.43.1
Sep28° / 26°53728.612.13.3
Oct28° / 26°27823.111.74.0
Nov29° / 26°518.211.45.7
Dec29° / 25°183.811.36.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in September, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 3% of September, with mostly cloudy or overcast conditions the remaining 95%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1595
2595
3496
4496
5496
6496
7397
8397
9397
10397
11397
12397
13397
14397
15397
16595
17595
18595
19694
20694
21694
22694
23793
24793
25793
26793
27793
28793
29793
30793

Chance of precipitation in September

Any precipitation

Ko Chang gets around 537 mm of rain over 28.6 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 95% and peaks near 96% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
195
295
395
496
596
696
796
896
996
1096
1195
1295
1395
1495
1595
1695
1795
1895
1995
2095
2195
2295
2394
2494
2594
2694
2794
2894
2994
3094

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 58% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
12971
23070
33268
43367
53466
63565
73664
83763
93862
103961
114060
124159
134258
144258
154357
164456
174456
184555
194555
204654
214654
224654
234753
244852
254852
264951
275050
285149
295248
305446

Wind in September

Winds average 15 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
117light breeze
217light breeze
317light breeze
417light breeze
517light breeze
617light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2413light breeze
2513light breeze
2613light breeze
2712light breeze
2812light breeze
2912calm
3012calm

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 6:03 AM to 6:03 AM, and sunset from 6:18 PM to 5:57 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.26:036:18
212.26:036:17
312.26:036:16
412.26:036:16
512.26:036:15
612.26:036:14
712.26:036:13
812.26:036:13
912.16:036:12
1012.16:036:11
1112.16:036:11
1212.16:036:10
1312.16:036:09
1412.16:036:09
1512.16:036:08
1612.16:036:07
1712.16:036:06
1812.06:036:06
1912.06:036:05
2012.06:036:04
2112.06:036:04
2212.06:036:03
2312.06:036:02
2412.06:036:01
2512.06:036:01
2612.06:036:00
2711.96:035:59
2811.96:035:59
2911.96:035:58
3011.96:035:57

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.28 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 4.28 kWh/m² to a high of 5.99 kWh/m² in April across the year — September's 4.28 kWh/m² sits near the bottom.

012345151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.4Bright
44.4Bright
54.4Bright
64.4Bright
74.3Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.2Bright
244.2Bright
254.3Bright
264.3Bright
274.3Bright
284.3Bright
294.3Bright
304.3Bright
Planning a trip in September

Hazard calendar for Ko Chang

In seasonPeak

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

Ko Chang sits in the Pacific typhoon belt; the season peaks July–October.

Ko Chang'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 Ko Chang?

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

3.3
Sightseeing
8th-best month of the year
3.6
Beach & pool
11th-best month of the year

September is a weaker month for outdoor sightseeing in Ko Chang.

What to pack for Ko Chang in September

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

In September, Ko Chang sees daytime highs around 28°C and nights near 26°C. Pack light clothes and rain gear. About 29 days see rain.

light clothesrain gear

Sea temperature near Ko Chang 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 21 km away) is warmest in May at about 31°C and coldest in January near 28°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
Jan28Tropical
Feb28Tropical
Mar29Tropical
Apr30Tropical
May31Tropical
Jun30Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Ko Chang 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 Ko Chang peaks around August 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 12 at about 9 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highAug 17UV 14Dec 12UV 9
UV index (midday)Level
Jan10Very high
Feb10Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun12Extreme
Jul12Extreme
Aug14Extreme
Sep12Extreme
Oct11Extreme
Nov9Very high
Dec9Very high

Air quality in Ko Chang 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 Ko Chang is worst in February — around 25 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (November, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodFeb 1424 µg/m³Nov 1410 µg/m³
PM2.5 (µg/m³)Level
Jan20Moderate
Feb25Moderate
Mar20Moderate
Apr16Moderate
May12Moderate
Jun12Moderate
Jul14Moderate
Aug12Good
Sep11Good
Oct11Good
Nov10Good
Dec11Good
Location & terrain

Where is Ko Chang?

Ko Chang sits at 12.0°N, 102.3°E, 0 m above sea level, in Thailand. The nearest listed city is Laem Ngop, 17 km away.

Topography around Ko Chang

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

Within 3 km, the terrain around Ko Chang has large variations in elevation — a maximum elevation change of 647 m around an average of 114 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 735 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,628 m.

The land around Ko Chang is covered by trees (67%) and water (29%) within 3 km, water (74%) and trees (25%) within 16 km, and water (55%) and trees (38%) within 80 km.

3 km
647 m
16 km
735 m
80 km
1,628 m
treesgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Laem Ngop 17 km · Trat 32 km · Khao Saming 37 km · Laem Sing 54 km · Chanthaburi 66 km · Khlong Yai 71 km · Tha Mai 72 km · Koh Kong 88 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 Ko Chang (12.0451°, 102.3003°, elevation 0 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).