Ko Lanta weather in May

In May, Ko Lanta sees average daytime highs of 29°C and overnight lows near 27°C, with 258 mm of rain across 25.2 wet days and about 12.3 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 7% of the time in May, and the air most often feels miserable.

Daylight stretches from about 12 h 18 min at the start of May to 12 h 24 min by month's end. Set against the rest of the year, May is Ko Lanta's 7th-clearest and 11th-windiest month. For the whole year in context, see Ko Lanta's year-round climate.

Daytime high
29°
2nd warmest
Overnight low
27°
12th coldest
Rainfall
258 mm
25.2 wet days
Daylight
12 h 18 min
6:10 AM – 6:30 PM
Cloud cover
81%
7th clearest
Wind
14 km/h
11th windiest
Solar energy
5.5 kWh/m²
Travel score
3.5
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical May day in Ko Lanta reaches about 29°C in the afternoon and slips back to 27°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 30°C. Set against its neighbours, May runs on par with April and on par with June.

24°26°28°30°32°151015202531
Avg high (°C)Avg low (°C)
12927
22927
32927
42927
52927
62927
72927
82927
92927
102927
112927
122927
132927
142927
152927
162927
172927
182927
192927
202927
212927
222927
232927
242927
252927
262927
272927
282927
292927
302927
312927

How May really feels in Ko Lanta

Once humidity and wind are folded in, May averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in May is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Ko Lanta weather by month

How May compares with the rest of the year at a glance. May is the 2nd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 26°466.311.66.2
Feb29° / 26°25411.86.3
Mar29° / 27°8310.911.95.4
Apr29° / 27°14819.912.24.1
May29° / 27°25825.212.33.5
Jun29° / 27°22921.912.43.8
Jul29° / 27°22722.112.43.9
Aug28° / 27°27022.612.24.0
Sep28° / 26°30224.4123.8
Oct28° / 26°32728.311.83.6
Nov28° / 26°2232311.74.2
Dec28° / 26°10512.311.65.4

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 7% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 10% of May, with mostly cloudy or overcast conditions the remaining 83%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12080
22080
32080
42080
52080
61882
71882
81882
91882
101882
111882
121783
131783
141783
151783
161783
171783
181783
191684
201684
211684
221684
231585
241684
251684
261585
271585
281486
291486
301387
311387

Chance of precipitation in May

Any precipitation

Ko Lanta gets around 258 mm of rain over 25.2 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 81% and peaks near 85% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
182
282
383
484
584
685
785
885
985
1085
1184
1284
1384
1483
1583
1682
1782
1881
1980
2080
2179
2278
2378
2478
2578
2678
2778
2879
2979
3079
3179

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the miserable band about 90% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
1892
2892
3892
4793
5793
6793
7793
8793
9892
10892
11892
12991
13991
14991
15991
16991
171090
181090
191090
201189
211189
221288
231288
241288
251288
261288
271288
281288
291387
301387
311387

Wind in May

Winds average 14 km/h in May.

Across May, daily wind ranges from about 13 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light breeze
3115light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 18 min at the start of May to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over May. Sunrise moves from 6:13 AM to 6:09 AM, and sunset from 6:29 PM to 6:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.36:136:29
212.36:136:29
312.36:126:29
412.36:126:29
512.36:126:29
612.36:126:29
712.36:116:29
812.36:116:29
912.36:116:29
1012.36:116:29
1112.36:106:29
1212.36:106:30
1312.36:106:30
1412.36:106:30
1512.36:106:30
1612.36:106:30
1712.36:096:30
1812.46:096:30
1912.46:096:31
2012.46:096:31
2112.46:096:31
2212.46:096:31
2312.46:096:31
2412.46:096:32
2512.46:096:32
2612.46:096:32
2712.46:096:32
2812.46:096:32
2912.46:096:33
3012.46:096:33
3112.46:096:33

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.5 kWh/m².

For context, solar energy here swings from a low near 4.66 kWh/m² to a high of 6.42 kWh/m² in March across the year — May's 5.5 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.7Bright
45.7Bright
55.7Bright
65.7Bright
75.6Bright
85.6Bright
95.6Bright
105.6Bright
115.5Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.5Bright
175.4Bright
185.4Bright
195.4Bright
205.4Bright
215.4Bright
225.4Bright
235.4Bright
245.4Bright
255.4Bright
265.4Bright
275.4Bright
285.4Bright
295.3Bright
305.3Bright
315.3Bright
Planning a trip in May

Hazard calendar for Ko Lanta

In seasonPeak

In May, Ko Lanta sits inside its cyclone and rainy season season. The full year is below, with each hazard's peak months called out.

Ko Lanta sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

Ko Lanta's rainy season runs April–November, when most of the year's rain falls.

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

Is May a good time to visit Ko Lanta?

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

3.5
Sightseeing
12th-best month of the year
4.4
Beach & pool
10th-best month of the year

May is a weaker month for outdoor sightseeing in Ko Lanta.

What to pack for Ko Lanta in May

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

In May, Ko Lanta sees daytime highs around 29°C and nights near 27°C. Pack light clothes and rain gear. Worth having: sun protection. About 25 days see rain.

light clothesrain gearsun protection

Sea temperature near Ko Lanta in May

The nearest coast averages about 30°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in May at about 30°C and coldest in January near 29°C.

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

28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar30Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Ko Lanta in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 Lanta peaks around February 22 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 22 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 22UV 13Nov 22UV 10
UV index (midday)Level
Jan11Extreme
Feb13Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun12Extreme
Jul11Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov10Extreme
Dec10Extreme

Air quality in Ko Lanta in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Ko Lanta is worst in April — around 16 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodGoodModerateApr 1115 µg/m³Aug 2011 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb14Moderate
Mar15Moderate
Apr16Moderate
May13Moderate
Jun13Moderate
Jul13Moderate
Aug11Good
Sep12Moderate
Oct12Good
Nov12Good
Dec13Moderate
Location & terrain

Where is Ko Lanta?

Ko Lanta sits at 7.5°N, 99.1°E, 0 m above sea level, in Thailand. The nearest listed city is Ko Phi Phi, 42 km away.

Topography around Ko Lanta

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

Within 3 km, the terrain around Ko Lanta has significant variations in elevation — a maximum elevation change of 481 m around an average of 77 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 487 m; within 80 km, large variations in elevation — a maximum elevation change of 1,003 m.

The land around Ko Lanta is covered by trees (53%) and water (41%) within 3 km, water (82%) within 16 km, and water (59%) and trees (36%) within 80 km.

3 km
481 m
16 km
487 m
80 km
1,003 m
treesgrasslandartificial surfaceswatermangroves
May weather nearby: Ko Phi Phi 42 km · Trang 58 km · Krabi 63 km · Ao Nang 65 km · Huai Yot 67 km · Ban Ko Sire 83 km · Ban Talat Yai 85 km · Phuket 86 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 Lanta (7.5336°, 99.0865°, 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).