Climate and average weather in Nam Som

In Nam Som, the summers are muggy, sweltering, showery, and partly cloudy and the winters are hot and mostly clear.

Best: late November to early February

Over the course of the year, the temperature in Nam Som typically varies from 17°C to 35°C, and is rarely below 12°C or above 39°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 Nam Som for warm-weather activities is from late November to early February.

Hottest
Apr
35°
Coldest
Dec
17°
Wettest
Aug
326 mm
Driest
Dec
9 mm
Rain / yr
1605 mm
162 wet days
Daylight
10.9–13.1 h
shortest–longest
Elevation
231 m
17.8°N
Clearest
Feb
29% cloud

Nam Som 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 late November to early February.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

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

Temperatures in Nam Som stay fairly even through the year, without a distinct hot or cool season. The warmest month is April, with an average high of 35°C and low of 24°C; the coolest is December, with an average low of 17°C and high of 28°C.

Days typically run about 9°C warmer than nights, with the widest day–night swing (around 13°C) in February.

10°15°20°25°30°35°40°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2917
Feb3118
Mar3422
Apr3524
May3325
Jun3225
Jul3225
Aug3125
Sep3124
Oct3123
Nov3020
Dec2817

How hot and cold Nam Som 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, Nam Som feels like about 40°C (around June 3). About 257 days a year carry some heat stress, and 77 of them tip into dangerous heat (feels-like above 39°C), peaking in June.

15°20°25°30°35°40°45°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan29291717
Feb32311818
Mar36342222
Apr39352424
May40332525
Jun40322525
Jul38322525
Aug38312525
Sep38312424
Oct34312323
Nov31302020
Dec28281717

Average hourly temperature in Nam Som

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 35°C, and coldest before dawn in December, near 17°C.

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

Nam Som 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
Jan29° / 17°101.611.17.1
Feb31° / 18°142.411.45.5
Mar34° / 22°396.911.93.6
Apr35° / 24°7812.812.42.5
May33° / 25°23623.112.82.3
Jun32° / 25°23122.8132.4
Jul32° / 25°26824.9132.5
Aug31° / 25°32626.312.62.6
Sep31° / 24°26624.412.12.8
Oct31° / 23°10512.311.64.4
Nov30° / 20°232.911.26.1
Dec28° / 17°91.3117.7

Chance of rain

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

Nam Som gets about 1605 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.

The wetter season lasts 5.8 months, from around Apr 19 to Oct 12, peaking in September at about 89% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Dec 13.

August is the wettest month by volume, with 326 mm over about 26 wet days; December is the driest, with 9 mm.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetSep 1 · 89%Dec 13 · 3%
Rain on a day (%)Rain days
Jan62
Feb82
Mar227
Apr4313
May7423
Jun7723
Jul8025
Aug8526
Sep8024
Oct4012
Nov103
Dec41

Monthly rainfall

Over a full year, Nam Som collects about 1605 mm of rain across 162 wet days — roughly 134 mm in an average month.

It doesn’t fall evenly. August is the wettest month with 326 mm, while December is the driest at just 9 mm. The three wettest months alone bring about 54% of the year’s total.

050100150200250300350JanFebMarAprMayJunJulAugSepOctNovDec10143978236231268326266105239
Rainfall (mm)Rain days
Jan102
Feb142
Mar397
Apr7813
May23623
Jun23123
Jul26825
Aug32626
Sep26624
Oct10512
Nov233
Dec91

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

In Nam Som, 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 9 and lasts for 6.7 months, ending around April 30. The clearest month is February, when the sky is clear, mostly clear, or partly cloudy 85% of the time on average.

The cloudier part of the year begins around May 1 and lasts for 5.3 months, ending around October 8. The cloudiest month is June, when it is overcast or mostly cloudy 94% 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%JanFebMarAprMayJunJulAugSepOctNovDecMar 1 · 87%Jun 11 · 5%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan7921
Feb8515
Mar7723
Apr6139
May2377
Jun694
Jul793
Aug793
Sep2179
Oct5446
Nov7426
Dec8020

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 June 14, brings about 13 h 06 min of light; the shortest, around December 13, only 10 h 54 min — a swing of roughly 2 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan11.16:495:52
Feb11.46:446:08
Mar11.96:256:17
Apr12.45:596:24
May12.85:436:32
Jun13.05:406:43
Jul13.05:486:46
Aug12.65:576:33
Sep12.16:036:09
Oct11.66:095:44
Nov11.26:225:31
Dec11.06:395:36

Sunny days

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

Nam Som averages about 11 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 22 days.

The sunnier stretch runs 6.1 months, from around Oct 15 to Apr 19. The sunniest month is February, with roughly 22 sunny days (bright).

The greyest month is August, down near 1 sunny days — about 98% fewer than the February peak.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyersunniergloomymixedbrightbrilliantFeb 2822 daysAug 20 days
Sunny daysSky
Jan20Bright
Feb20Bright
Mar19Bright
Apr12Mixed
May3Gloomy
Jun1Gloomy
Jul1Gloomy
Aug1Gloomy
Sep3Gloomy
Oct11Mixed
Nov17Bright
Dec20Bright

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.

In Nam Som, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 8.2 months, from around March 11 to November 14. The muggiest month is April, when the air feels humid, muggy or worse about 99% of the time.

The most comfortable stretch runs from around November 15 to March 10, and December is the most comfortable month — the air is dry or comfortable 41% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecDec 25 · 50%Apr 22 · 0%miserablehumidmuggyoppressivecomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan1532341720
Feb925342560
Mar282341260
Apr01423666
May00044452
Jun00002674
Jul00003565
Aug00003466
Sep00023761
Oct025205518
Nov4102537241
Dec1724322340

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.

Wind in Nam Som is steady company: average speeds sit near 6 km/hcalm — in every month of the year, with no meaningful windy or calm season.

051015JanFebMarAprMayJunJulAugSepOctNovDeccalmlight breezeFeb 21 · 7 km/hSep 13 · 5 km/h
Wind speed (km/h)Feels
Jan7calm
Feb7calm
Mar7calm
Apr6calm
May5calm
Jun6calm
Jul6calm
Aug6calm
Sep5calm
Oct5calm
Nov6calm
Dec6calm

Hazard calendar for Nam Som

In seasonPeak

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

Nam Som's monsoon runs May–September, when most of the year's rain falls.

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

Best time to visit Nam Som

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around late January, Nam Som 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 Nam Som for general outdoor tourist activities is from late November to early February, with a peak score in the last week of December.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationDec 23 · 8.1

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
Jan7.1good
Feb5.5good
Mar3.6fair
Apr2.5poor
May2.3poor
Jun2.4poor
Jul2.5poor
Aug2.6poor
Sep2.8poor
Oct4.4fair
Nov6.1good
Dec7.6ideal

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 Nam Som for hot-weather activities is from late October to mid March, with a peak score in the last week of January.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationJan 22 · 8.8

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 Nam Som, 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.

For a warm-season trip around April (highs near 35°C), the essentials are light clothes, rain gear and sun protection. In the cold season around December (highs near 28°C), pack light clothes and sun protection.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In April, Nam Som sees daytime highs around 35°C and nights near 24°C. Pack light clothes and sun protection. Worth having: rain gear. About 13 days see rain.

UV index (midday) in Nam Som 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 Nam Som peaks around August 12 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 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 12UV 13Dec 14UV 8
UV index (midday)Level
Jan9Very high
Feb10Very high
Mar12Extreme
Apr11Extreme
May11Extreme
Jun13Extreme
Jul13Extreme
Aug13Extreme
Sep11Extreme
Oct10Extreme
Nov8Very high
Dec8Very high

Average hourly UV index in Nam Som

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)
Jan6.54
Feb75
Mar7.56
Apr85.5
May86
Jun8.56.5
Jul8.56.5
Aug8.56.5
Sep7.55.5
Oct75
Nov6.54
Dec63.5

Air quality in Nam Som 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 Nam Som is worst in April — around 122 µg/m³ PM2.5 (unhealthy), about 8.3× the cleanest month (November, 15 µg/m³).

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

0306090120150JanFebMarAprMayJunJulAugSepOctNovDecModerateUnhealthyModerateApr 11119 µg/m³Nov 1615 µg/m³
PM2.5 (µg/m³)Level
Jan22Moderate
Feb37Poor
Mar108Unhealthy
Apr122Unhealthy
May28Moderate
Jun16Moderate
Jul15Moderate
Aug16Moderate
Sep15Moderate
Oct16Moderate
Nov15Moderate
Dec17Moderate
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Nam Som 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. Nam Som banks about 6,125 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)
Jan394
Feb413
Mar545
Apr582
May591
Jun566
Jul572
Aug559
Sep534
Oct525
Nov452
Dec393

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.

Nam Som receives about 4.9 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.2 and 6.0 kWh/m².

The brighter stretch of the year lasts 4.1 months, from around Jan 26 to May 31. The brightest month is April, averaging about 6.0 kWh/m² (bright).

The dimmest month is August, down near 4.2 kWh/m² — roughly 30% less than the April peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseApr 126.0 kWhAug 54.2 kWh
Solar energy (kWh/m²)Level
Jan4.7Bright
Feb5.4Bright
Mar5.9Bright
Apr6.0Intense
May5.3Bright
Jun4.8Bright
Jul4.5Bright
Aug4.2Bright
Sep4.4Bright
Oct4.7Bright
Nov4.6Bright
Dec4.5Bright

Where is Nam Som?

Nam Som sits at 17.8°N, 102.2°E, 231 m above sea level, in Thailand. The nearest listed city is Tha Bo, 42 km away.

Topography around Nam Som

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

Within 3 km, the terrain around Nam Som has only modest variations in elevation — a maximum elevation change of 156 m around an average of 227 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 559 m; within 80 km, large variations in elevation — a maximum elevation change of 951 m.

The land around Nam Som is covered by trees (51%) and cropland (36%) within 3 km, trees (66%) and cropland (28%) within 16 km, and trees (59%) and cropland (34%) within 80 km.

3 km
156 m
16 km
559 m
80 km
951 m
treesgrasslandcroplandartificial surfaceswater
Nearby: Tha Bo 42 km · Vientiane 49 km · Na Klang 52 km · Kut Chap 55 km · Erawan 58 km · Loei 58 km · Nong Khai 60 km · Nong Bua Lamphu 68 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 Nam Som (17.7704°, 102.1895°, elevation 231 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. 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).