Lak Si weather in September

In September, Lak Si sees average daytime highs of 33°C and overnight lows near 26°C, with 255 mm of rain across 25.5 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 Lak Si's 9th-clearest and 10th-windiest month. For the whole year in context, see Lak Si's year-round climate.

Daytime high
33°
8th warmest
Overnight low
26°
7th coldest
Rainfall
255 mm
25.5 wet days
Daylight
12 h 06 min
6:10 AM – 6:14 PM
Cloud cover
86%
9th clearest
Wind
7 km/h
10th windiest
Solar energy
4.58 kWh/m²
Travel score
2.1
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 Lak Si reaches about 33°C in the afternoon and slips back to 26°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 35°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°40°151015202530
Avg high (°C)Avg low (°C)
13326
23326
33326
43326
53326
63326
73326
83326
93326
103326
113326
123326
133326
143326
153326
163326
173326
183326
193326
203326
213326
223326
233326
243326
253326
263326
273326
283326
293226
303226

How September really feels in Lak Si

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.

Lak Si 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°132.711.34.7
Feb34° / 24°132.611.53.9
Mar35° / 26°46711.92.8
Apr36° / 27°7312.112.31.8
May35° / 27°15422.212.61.7
Jun34° / 27°1522312.81.9
Jul34° / 26°1502412.72.0
Aug33° / 26°16824.412.52.1
Sep33° / 26°25525.512.12.1
Oct32° / 25°17419.811.72.9
Nov33° / 24°385.911.44.1
Dec32° / 22°91.811.24.9

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 7% of September, with mostly cloudy or overcast conditions the remaining 91%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1694
2595
3694
4694
5694
6694
7694
8694
9694
10694
11694
12793
13892
14892
15892
16892
17892
18991
191090
201189
211288
221288
231288
241387
251387
261387
271486
281486
291486
301585

Chance of precipitation in September

Any precipitation

Lak Si gets around 255 mm of rain over 25.5 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 86% and peaks near 87% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
184
284
385
485
585
685
785
886
986
1086
1186
1286
1387
1487
1587
1687
1787
1887
1987
2086
2186
2286
2385
2485
2585
2685
2785
2884
2984
3084

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 83% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
12377
22377
32377
42377
52377
62377
72377
82377
92278
102278
112179
122179
132080
141981
151882
161783
171684
181585
191486
201387
211288
221189
231090
241090
25991
26991
27892
28892
29892
30892

Wind in September

Winds average 7 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.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
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 6:09 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)
112.36:096:26
212.36:096:25
312.26:096:24
412.26:096:23
512.26:096:23
612.26:096:22
712.26:096:21
812.26:106:20
912.26:106:20
1012.26:106:19
1112.16:106:18
1212.16:106:17
1312.16:106:17
1412.16:106:16
1512.16:106:15
1612.16:106:14
1712.16:106:14
1812.06:106:13
1912.06:106:12
2012.06:106:11
2112.06:106:10
2212.06:106:10
2312.06:106:09
2412.06:106:08
2512.06:106:07
2611.96:106:07
2711.96:106:06
2811.96:106:05
2911.96:106:04
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 4.58 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 4.58 kWh/m² to a high of 6.19 kWh/m² in April across the year — September's 4.58 kWh/m² sits near the bottom.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.7Bright
44.7Bright
54.7Bright
64.7Bright
74.7Bright
84.7Bright
94.6Bright
104.6Bright
114.6Bright
124.6Bright
134.6Bright
144.6Bright
154.5Bright
164.5Bright
174.5Bright
184.5Bright
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 Lak Si

In seasonPeak

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

Lak Si sits in the Pacific typhoon belt; the season peaks July–October.

Lak Si'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 Lak Si?

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

2.1
Sightseeing
7th-best month of the year
3.7
Beach & pool
11th-best month of the year

September is a weaker month for outdoor sightseeing in Lak Si.

What to pack for Lak Si in September

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

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

light clothesrain gearsun protection

Sea temperature near Lak Si 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 57 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 Lak Si 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 Lak Si peaks around August 15 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 19 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 15UV 13Nov 19UV 8
UV index (midday)Level
Jan9Very high
Feb9Very high
Mar12Extreme
Apr11Extreme
May10Extreme
Jun12Extreme
Jul12Extreme
Aug13Extreme
Sep12Extreme
Oct10Very high
Nov8Very high
Dec8Very high

Air quality in Lak Si 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 Lak Si is worst in January — around 83 µg/m³ PM2.5 (unhealthy), about 1.9× the cleanest month (July, 43 µg/m³).

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

0306090JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorUnhealthyJan 2382 µg/m³Jul 2443 µg/m³
PM2.5 (µg/m³)Level
Jan83Unhealthy
Feb81Unhealthy
Mar70Unhealthy
Apr64Unhealthy
May54Poor
Jun44Poor
Jul43Poor
Aug43Poor
Sep54Poor
Oct66Unhealthy
Nov67Unhealthy
Dec66Unhealthy
Location & terrain

Where is Lak Si?

Lak Si sits at 13.9°N, 100.6°E, 8 m above sea level, in Thailand. The nearest listed city is Anusawari, 4.0 km away.

Topography around Lak Si

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

Within 3 km, the terrain around Lak Si has only modest variations in elevation — a maximum elevation change of 52 m around an average of 5 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 700 m.

The land around Lak Si is covered by artificial surfaces (71%) within 3 km, artificial surfaces (63%) and trees (21%) within 16 km, and cropland (38%) and water (21%) within 80 km.

3 km
52 m
16 km
52 m
80 km
700 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Anusawari 4.0 km · Lat Yao 5.0 km · Sena Nikhom 6.0 km · Chorakhe Bua 6.0 km · Chatuchak 7.0 km · Chatuchak subdistrict 7.0 km · Chan Kasem 7.0 km · Tha Raeng 7.0 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 Lak Si (13.8872°, 100.5792°, elevation 8 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).