Climate and average weather in Lahān

In Lahān, the summers are sweltering, fairly dry, and mostly clear and the winters are warm and mostly clear.

Best: early January to early March

Over the course of the year, the temperature in Lahān typically varies from 10°C to 35°C, and is rarely below 7°C or above 39°C. April is the hottest month of the year, while January is the coldest.

Based on the travel score, the best times of year to visit Lahān for warm-weather activities are from early January to early March and early November to late December.

Hottest
Apr
35°
Coldest
Jan
10°
Wettest
Jul
413 mm
Driest
Nov
4 mm
Rain / yr
1411 mm
135 wet days
Daylight
10.3–13.7 h
shortest–longest
Elevation
123 m
26.7°N
Clearest
Nov
19% cloud

Lahān is municipality in Siraha District, Nepal.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Lahān 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 early January to early March.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

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

The hot season lasts 3.3 months, from March 18 to June 24, with daily high temperatures above 32°C. The hottest month of the year in Lahān is April, with an average high of 35°C and low of 22°C.

The cool season lasts 1.9 months, from December 12 to February 6, with daily high temperatures below 24°C. The coldest month of the year in Lahān is January, with an average low of 10°C and high of 22°C.

Days typically run about 10°C warmer than nights, with the widest day–night swing (around 14°C) in March.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2210
Feb2613
Mar3117
Apr3522
May3424
Jun3326
Jul3126
Aug3126
Sep3125
Oct3021
Nov2816
Dec2411

How hot and cold Lahān 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, Lahān feels like about 40°C (around June 17). About 213 days a year carry some heat stress, and 42 of them tip into dangerous heat (feels-like above 39°C), peaking in June.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan22221010
Feb26261313
Mar31311717
Apr35352222
May37342424
Jun39332626
Jul39312626
Aug39312626
Sep37312525
Oct32302121
Nov28281516
Dec24241111

Average hourly temperature in Lahān

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 January, near 10°C.

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

Lahān 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
Jan22° / 10°121.810.58.5
Feb26° / 13°122.111.18.5
Mar31° / 17°122.411.85.6
Apr35° / 22°315.612.63.1
May34° / 24°9713.713.32.7
Jun33° / 26°2522313.62.5
Jul31° / 26°41327.613.52.6
Aug31° / 26°2792712.92.6
Sep31° / 25°24023.112.23.2
Oct30° / 21°576.911.45.8
Nov28° / 16°40.510.78.3
Dec24° / 11°40.810.49.1

Chance of rain

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

Lahān gets about 1411 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 5.0 months, from around May 9 to Oct 8, peaking in July at about 92% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Nov 22.

July is the wettest month by volume, with 413 mm over about 28 wet days; November is the driest, with 4 mm.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetJul 5 · 92%Nov 22 · 1%
Rain on a day (%)Rain days
Jan62
Feb72
Mar82
Apr206
May4414
Jun7723
Jul8928
Aug8727
Sep7523
Oct247
Nov21
Dec31

Monthly rainfall

Over a full year, Lahān collects about 1411 mm of rain across 135 wet days — roughly 118 mm in an average month.

It doesn’t fall evenly. July is the wettest month with 413 mm, while November is the driest at just 4 mm. The three wettest months alone bring about 67% of the year’s total.

050100150200250300350400450JanFebMarAprMayJunJulAugSepOctNovDec12121231972524132792405744
Rainfall (mm)Rain days
Jan122
Feb122
Mar122
Apr316
May9714
Jun25223
Jul41328
Aug27927
Sep24023
Oct577
Nov41
Dec41

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

In Lahān, 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 2 and lasts for 8.1 months, ending around June 4. The clearest month is November, when the sky is clear, mostly clear, or partly cloudy 93% of the time on average.

The cloudier part of the year begins around June 5 and lasts for 3.9 months, ending around October 1. The cloudiest month is July, when it is overcast or mostly cloudy 93% 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%JanFebMarAprMayJunJulAugSepOctNovDecNov 5 · 93%Aug 1 · 5%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan8317
Feb8416
Mar8614
Apr8317
May7822
Jun3961
Jul793
Aug1090
Sep3862
Oct8317
Nov937
Dec8911

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 13, brings about 13 h 42 min of light; the shortest, around January 1, only 10 h 18 min — a swing of roughly 3 h 24 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan10.56:545:23
Feb11.16:425:45
Mar11.86:156:03
Apr12.65:406:18
May13.35:166:35
Jun13.65:096:49
Jul13.55:196:51
Aug12.95:356:32
Sep12.25:495:58
Oct11.46:035:25
Nov10.76:245:04
Dec10.46:455:05

Sunny days

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

Lahān averages about 15 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 26 days.

The sunnier stretch runs 7.5 months, from around Oct 3 to May 19. The sunniest month is November, with roughly 26 sunny days (brilliant).

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

051015202530JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyersunniergloomymixedbrightbrilliantNov 326 daysJul 170 days
Sunny daysSky
Jan21Bright
Feb19Bright
Mar22Bright
Apr18Bright
May16Bright
Jun6Gloomy
Jul0Gloomy
Aug1Gloomy
Sep7Gloomy
Oct22Bright
Nov25Brilliant
Dec24Brilliant

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 Lahān, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 6.7 months, from around April 19 to November 9. The muggiest month is June, when the air feels humid, muggy or worse about 100% of the time.

The most comfortable stretch runs from around November 10 to April 18, and January is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 6 · 100%Jun 16 · 0%comfortablehumidmuggymiserableoppressivedrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan9190000
Feb72244000
Mar63259300
Apr3116262350
May341034426
Jun00133363
Jul0000496
Aug0000496
Sep00022771
Oct051532399
Nov1840321010
Dec73252000

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 Lahān is typically calm, near 7 km/h, and varies little with the seasons.

The windier part of the year lasts 6.4 months, from around Feb 24 to Sep 6. The windiest month is April, averaging about 9 km/h (calm).

The calmer part of the year runs from around Sep 7 to Feb 23, with October the calmest month at about 5 km/h.

051015JanFebMarAprMayJunJulAugSepOctNovDeccalmerwindiercalmercalmlight breezeApr 15 · 9 km/hOct 27 · 5 km/h
Wind speed (km/h)Feels
Jan5calm
Feb6calm
Mar8calm
Apr9calm
May9calm
Jun8calm
Jul8calm
Aug8calm
Sep6calm
Oct5calm
Nov5calm
Dec5calm

Hazard calendar for Lahān

In seasonPeak

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

Lahān's monsoon runs June–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 Lahān

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around mid January, Lahān is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.

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 Lahān for general outdoor tourist activities is from early November to early March, with a peak score in the second week of December.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationDec 12 · 9.2

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
Jan8.5ideal
Feb8.4ideal
Mar5.6good
Apr3.1poor
May2.7poor
Jun2.5poor
Jul2.6poor
Aug2.6poor
Sep3.3poor
Oct5.8good
Nov8.3ideal
Dec9.0ideal

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best times of year to visit Lahān for hot-weather activities run from early February to late March and again from mid October to mid December, with a peak score in the first week of November.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationNov 4 · 9.2

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 Lahān, 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 and sun protection. In the cold season around January (highs near 22°C), pack light clothes.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In April, Lahān sees daytime highs around 35°C and nights near 22°C. Pack light clothes and sun protection. About 6 days see rain.

UV index (midday) in Lahān 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 Lahān peaks around July 19 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 18 at about 4 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeVery highModerateJul 19UV 11Jan 18UV 4
UV index (midday)Level
Jan4Moderate
Feb4Moderate
Mar9Very high
Apr7Very high
May8Very high
Jun7High
Jul12Extreme
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec4Moderate

Average hourly UV index in Lahān

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 July the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6 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)
Jan30
Feb40
Mar6.54
Apr74
May7.54.5
Jun7.54
Jul8.56
Aug85
Sep74.5
Oct61.5
Nov40
Dec3.50

Air quality in Lahān 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 Lahān is worst in January — around 169 µg/m³ PM2.5 (very unhealthy), about 4.9× the cleanest month (July, 35 µg/m³).

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

0306090120150180JanFebMarAprMayJunJulAugSepOctNovDecVery unhealthyUnhealthyPoorUnhealthyJan 12167 µg/m³Jul 2036 µg/m³
PM2.5 (µg/m³)Level
Jan169Very unhealthy
Feb138Unhealthy
Mar107Unhealthy
Apr87Unhealthy
May70Unhealthy
Jun57Unhealthy
Jul35Moderate
Aug43Poor
Sep55Unhealthy
Oct87Unhealthy
Nov125Unhealthy
Dec160Very unhealthy
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Lahān 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. Lahān banks about 5,319 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around May.

02,0004,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan186
Feb258
Mar442
Apr548
May602
Jun571
Jul566
Aug565
Sep527
Oct474
Nov344
Dec236

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.

Lahān receives about 4.6 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 3.6 and 6.3 kWh/m².

The brighter stretch of the year lasts 4.1 months, from around Feb 14 to Jun 17. The brightest month is April, averaging about 6.3 kWh/m² (intense).

The dimmest month is December, down near 3.7 kWh/m² — roughly 42% less than the April peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseApr 166.3 kWhDec 143.6 kWh
Solar energy (kWh/m²)Level
Jan3.9Moderate
Feb4.6Bright
Mar5.8Bright
Apr6.3Intense
May5.9Bright
Jun4.7Bright
Jul3.8Moderate
Aug3.9Moderate
Sep4.0Bright
Oct4.4Bright
Nov4.0Bright
Dec3.6Moderate

Where is Lahān?

Lahān sits at 26.7°N, 86.5°E, 123 m above sea level, in Nepal. The nearest listed city is Triyuga, 23 km away.

JanakpurInaruwaJaleshwarĪṭahari̇̄Dharān

Topography around Lahān

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

Within 3 km, the terrain around Lahān has only modest variations in elevation — a maximum elevation change of 32 m around an average of 115 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 367 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,111 m.

The land around Lahān is covered by cropland (61%) within 3 km, cropland (54%) and trees (38%) within 16 km, and cropland (47%) and trees (45%) within 80 km.

3 km
32 m
16 km
367 m
80 km
3,111 m
treesgrasslandcroplandartificial surfacesbare terrainwater
Nearby: Triyuga 23 km · Siraha 28 km · Rājbirāj 33 km · Janakpur 55 km · Inaruwa 67 km · Jaleshwar 68 km · Īṭahari̇̄ 79 km · Dharān 80 km

Nepal travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / D / M
230 V · 50 Hz
Prices
≈ 24% of US
price level, 2025
GDP per capita
$1,536
2025
Happiness
5.1 / 10
World Happiness, 2025
Safe drinking water
16%
of population, 2024
Homicide rate
2.1
per 100k, 2020
Road deaths
16.3
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
Moderate
EF EPI 514
Religion
Hindu 81%Buddhist 8%Muslim 5%Kirat 3%

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 Lahān (26.7202°, 86.4826°, elevation 123 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).