Climate and average weather in Sam Roi Yot

In Sam Roi Yot, the weather is muggy, sweltering, wet, and partly cloudy and remarkably steady, with daytime highs holding near sweltering levels all year. The wettest stretch peaks around October.

Best: mid November to early February

Over the course of the year, the temperature in Sam Roi Yot typically varies from 21°C to 34°C, and is rarely below 18°C or above 37°C. April is the hottest month of the year, while December is the coldest.

Based on the travel score, the best time of year to visit Sam Roi Yot for warm-weather activities is from mid November to early February.

Hottest
Apr
34°
Coldest
Dec
21°
Wettest
Oct
232 mm
Driest
Dec
16 mm
Rain / yr
1437 mm
199 wet days
Daylight
11.3–12.7 h
shortest–longest
Elevation
17 m
12.3°N
Clearest
Feb
39% cloud

Sam Roi Yot weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid November to early February.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Sam Roi Yot, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

Temperatures in Sam Roi Yot stay fairly even through the year, without a distinct hot or cool season. The warmest month is April, with an average high of 34°C and low of 25°C; the coolest is December, with an average low of 21°C and high of 29°C.

Days typically run about 8°C warmer than nights, with the widest day–night swing (around 10°C) in February.

15°20°25°30°35°40°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan3021
Feb3222
Mar3323
Apr3425
May3325
Jun3225
Jul3124
Aug3124
Sep3124
Oct3023
Nov3023
Dec2921

How hot and cold Sam Roi Yot really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the hottest afternoons, once humidity is folded in, Sam Roi Yot feels like about 40°C (around April 26). About 306 days a year carry some heat stress, and 31 of them tip into dangerous heat (feels-like above 39°C), peaking in April.

20°25°30°35°40°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan32302121
Feb34322222
Mar37332323
Apr39342525
May39332525
Jun37322525
Jul35312424
Aug35312424
Sep35312424
Oct34302323
Nov32302323
Dec31292121

Average hourly temperature in Sam Roi Yot

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on April afternoons, near 34°C, and coldest before dawn in December, near 21°C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Sam Roi Yot weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 21°294.711.45.7
Feb32° / 22°184.611.64.8
Mar33° / 23°6810.711.93.5
Apr34° / 25°961712.32.5
May33° / 25°18025.412.62.1
Jun32° / 25°14323.312.72.6
Jul31° / 24°17924.512.62.8
Aug31° / 24°18224.712.42.8
Sep31° / 24°23026.112.12.6
Oct30° / 23°23224.811.73.3
Nov30° / 23°629.711.45.2
Dec29° / 21°163.411.36.2

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Sam Roi Yot gets about 1437 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.

The wetter season lasts 6.6 months, from around Apr 13 to Oct 30, peaking in October at about 91% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Dec 22.

October is the wettest month by volume, with 232 mm over about 25 wet days; December is the driest, with 16 mm.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetOct 1 · 91%Dec 22 · 8%
Rain on a day (%)Rain days
Jan145
Feb175
Mar3411
Apr5817
May8125
Jun7823
Jul7925
Aug8025
Sep8726
Oct7825
Nov3310
Dec123

Monthly rainfall

Over a full year, Sam Roi Yot collects about 1437 mm of rain across 199 wet days — roughly 120 mm in an average month.

It doesn’t fall evenly. October is the wettest month with 232 mm, while December is the driest at just 16 mm. The three wettest months alone bring about 45% of the year’s total.

050100150200250JanFebMarAprMayJunJulAugSepOctNovDec291868961801431791822302326216
Rainfall (mm)Rain days
Jan295
Feb185
Mar6811
Apr9617
May18025
Jun14323
Jul17925
Aug18225
Sep23026
Oct23225
Nov6210
Dec163

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Sam Roi Yot, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around October 29 and lasts for 6.0 months, ending around April 30. The clearest month is February, when the sky is clear, mostly clear, or partly cloudy 77% of the time on average.

The cloudier part of the year begins around May 1 and lasts for 5.9 months, ending around October 28. The cloudiest month is August, when it is overcast or mostly cloudy 96% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecFeb 11 · 78%Jul 31 · 3%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan6832
Feb7723
Mar6535
Apr4951
May1783
Jun694
Jul595
Aug496
Sep595
Oct2080
Nov5050
Dec6238

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around May 29, brings about 12 h 42 min of light; the shortest, around January 1, only 11 h 18 min — a swing of roughly 1 h 24 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan11.46:496:10
Feb11.66:476:23
Mar11.96:336:28
Apr12.36:136:29
May12.66:006:34
Jun12.75:596:42
Jul12.66:066:46
Aug12.46:126:37
Sep12.16:136:17
Oct11.76:145:57
Nov11.46:235:49
Dec11.36:385:55

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Sam Roi Yot averages about 7 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 18 days.

The sunnier stretch runs 5.8 months, from around Oct 31 to Apr 24. The sunniest month is February, with roughly 18 sunny days (bright).

The greyest month is September, down near 0 sunny days — about 99% fewer than the February peak.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyersunniergloomymixedbrightbrilliantFeb 1118 daysSep 50 days
Sunny daysSky
Jan15Mixed
Feb16Bright
Mar14Mixed
Apr8Mixed
May2Gloomy
Jun0Gloomy
Jul0Gloomy
Aug0Gloomy
Sep0Gloomy
Oct3Gloomy
Nov10Mixed
Dec13Mixed

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

Sam Roi Yot is humid all year round — on a typical day the air feels at least humid, and there is no real dry season to wait for.

The stickiest month is March, when it feels muggy, oppressive or miserable about 95% of the time. Even in December, the mildest month, the air is dry or comfortable only 13% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecDec 25 · 19%Mar 26 · 0%miserablemuggyoppressivehumidcomfortablecomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan292338280
Feb141435460
Mar01421713
Apr00077914
May00007128
Jun00017920
Jul0000928
Aug0000946
Sep0000919
Oct00167914
Nov01928566
Dec2112335290

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Sam Roi Yot is typically calm, near 8 km/h, and varies moderately with the seasons.

The windier part of the year lasts 4.0 months, from around May 21 to Sep 18. The windiest month is August, averaging about 11 km/h (calm).

The calmer part of the year runs from around Sep 19 to Nov 22, with October the calmest month at about 7 km/h.

051015JanFebMarAprMayJunJulAugSepOctNovDeccalmerwindiercalmercalmlight breezeAug 2 · 12 km/hOct 12 · 6 km/h
Wind speed (km/h)Feels
Jan8calm
Feb7calm
Mar7calm
Apr7calm
May8calm
Jun10calm
Jul11calm
Aug11calm
Sep9calm
Oct7calm
Nov8calm
Dec9calm

Hazard calendar for Sam Roi Yot

In seasonPeak

When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.

Sam Roi Yot sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

Sam Roi Yot's rainy season runs May–October, when most of the year's rain falls.

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

Best time to visit Sam Roi Yot

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Sam Roi Yot throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late January, Sam Roi Yot is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Sam Roi Yot for general outdoor tourist activities is from mid November to early February, with a peak score in the last week of December.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationDec 23 · 6.4

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan5.7good
Feb4.8fair
Mar3.5poor
Apr2.5poor
May2.2poor
Jun2.6poor
Jul2.8poor
Aug2.8poor
Sep2.7poor
Oct3.3poor
Nov5.1fair
Dec6.2good

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Sam Roi Yot for hot-weather activities is from mid November to mid March, with a peak score in the last week of December.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationDec 23 · 8.4

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Sam Roi Yot, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

Sam Roi Yot packs about the same all year — highs hold near 34°C. Across the year the things worth having are light clothes, rain gear and sun protection.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In April, Sam Roi Yot sees daytime highs around 34°C and nights near 25°C. Pack light clothes, rain gear and sun protection. About 17 days see rain.

Sea temperature near Sam Roi Yot

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

The sea at the nearest coast (about 30 km away) is warmest in May at about 30°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
Feb28Warm
Mar29Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec28Warm

UV index (midday) in Sam Roi Yot by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in Sam Roi Yot peaks around August 16 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 23 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 16UV 14Nov 23UV 9
UV index (midday)Level
Jan9Very high
Feb10Extreme
Mar12Extreme
Apr12Extreme
May12Extreme
Jun12Extreme
Jul12Extreme
Aug14Extreme
Sep12Extreme
Oct11Extreme
Nov9Very high
Dec9Very high

Average hourly UV index in Sam Roi Yot

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in August the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan74.5
Feb75
Mar86
Apr86
May8.56
Jun86
Jul8.56.5
Aug8.56.5
Sep86
Oct7.55.5
Nov6.54.5
Dec74.5

Air quality in Sam Roi Yot by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.

Air quality in Sam Roi Yot is worst in April — around 26 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (September, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateApr 1025 µg/m³Sep 1211 µg/m³
PM2.5 (µg/m³)Level
Jan24Moderate
Feb24Moderate
Mar25Moderate
Apr26Moderate
May16Moderate
Jun12Moderate
Jul13Moderate
Aug12Good
Sep11Good
Oct14Moderate
Nov19Moderate
Dec20Moderate
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Sam Roi Yot is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Sam Roi Yot banks about 6,324 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around April.

02,0004,0006,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan481
Feb467
Mar564
Apr579
May590
Jun550
Jul550
Aug546
Sep520
Oct516
Nov484
Dec476

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Sam Roi Yot receives about 5.0 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.1 and 6.2 kWh/m².

The brighter stretch of the year lasts 5.3 months, from around Dec 19 to May 29. The brightest month is April, averaging about 6.1 kWh/m² (intense).

The dimmest month is October, down near 4.3 kWh/m² — roughly 30% less than the April peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecbrighterdimmerdimmoderatebrightintenseApr 116.2 kWhOct 34.1 kWh
Solar energy (kWh/m²)Level
Jan5.2Bright
Feb5.8Bright
Mar6.0Intense
Apr6.1Intense
May5.3Bright
Jun4.8Bright
Jul4.4Bright
Aug4.4Bright
Sep4.3Bright
Oct4.2Bright
Nov4.8Bright
Dec5.0Bright

Where is Sam Roi Yot?

Sam Roi Yot sits at 12.3°N, 99.9°E, 17 m above sea level, in Thailand. The nearest listed city is Pran Buri, 13 km away.

PhetchaburiKhao Yoi

Topography around Sam Roi Yot

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sam Roi Yot.

Within 3 km, the terrain around Sam Roi Yot has only modest variations in elevation — a maximum elevation change of 144 m around an average of 12 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 573 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,303 m.

The land around Sam Roi Yot is covered by trees (47%) and grassland (29%) within 3 km, trees (57%) within 16 km, and trees (56%) and water (35%) within 80 km.

3 km
144 m
16 km
573 m
80 km
1,303 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
Nearby: Pran Buri 13 km · Kui Buri 21 km · Hua Hin 35 km · Prachuap Khiri Khan 51 km · Cha-am 60 km · Tha Yang 76 km · Phetchaburi 94 km · Khao Yoi 108 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 Sam Roi Yot (12.2708°, 99.872°, elevation 17 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).