Lahān weather in September

In September, Lahān sees average daytime highs of 31°C and overnight lows near 25°C, with 240 mm of rain across 23.1 wet days and about 12.2 hours of daylight. It is the 7th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°C through the month. The sky is clear or mostly clear about 22% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 36 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Lahān's 10th-clearest and 7th-windiest month. For the whole year in context, see Lahān's year-round climate.

Daytime high
31°
7th warmest
Overnight low
25°
9th coldest
Rainfall
240 mm
23.1 wet days
Daylight
12 h 12 min
5:49 AM – 5:58 PM
Cloud cover
68%
10th clearest
Wind
7 km/h
7th windiest
Solar energy
4 kWh/m²
Travel score
3.2
out of 10

Lahān is municipality in Siraha District, Nepal.

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°C through the month.

A typical September day in Lahān reaches about 31°C in the afternoon and slips back to 25°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 33°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13125
23125
33125
43125
53125
63125
73125
83125
93125
103125
113125
123125
133125
143125
153125
163125
173125
183125
193124
203124
213124
223024
233024
243024
253024
263024
273024
283024
293024
303023

How September really feels in Lahān

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
heat index over the day's high
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.

Lahān weather by month

How September compares with the rest of the year at a glance. September is the 7th-warmest and 4th-wettest month here — the current month is highlighted below.

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

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 62%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12179
22278
32377
42476
52575
62773
72773
82971
93070
103169
113268
123367
133565
143565
153565
163664
173763
183862
194060
204060
214258
224456
234555
244753
254951
265248
275446
285743
295941
306139

Chance of precipitation in September

Any precipitation

Lahān gets around 240 mm of rain over 23.1 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 76% and peaks near 85% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
185
285
385
485
584
684
783
882
981
1081
1180
1279
1379
1478
1578
1678
1777
1876
1976
2075
2173
2272
2371
2469
2568
2666
2764
2862
2959
3057

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 72% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
10991
20991
301090
401090
501189
601288
701387
801486
901585
1001684
1101783
1201882
1301981
1402179
1512277
1612475
1712673
1812772
1922969
2023266
2123464
2233661
2333859
2434156
2544452
2644650
2744947
2855144
2965440
3065737

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 36 min at the start of September to 11 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 48 minutes over September. Sunrise moves from 5:42 AM to 5:55 AM, and sunset from 6:15 PM to 5:42 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.65:426:15
212.55:436:14
312.55:436:13
412.55:436:12
512.45:446:11
612.45:446:10
712.45:456:09
812.45:456:07
912.35:466:06
1012.35:466:05
1112.35:476:04
1212.35:476:03
1312.25:476:02
1412.25:486:00
1512.25:485:59
1612.25:495:58
1712.15:495:57
1812.15:505:56
1912.15:505:55
2012.05:505:53
2112.05:515:52
2212.05:515:51
2312.05:525:50
2411.95:525:49
2511.95:535:47
2611.95:535:46
2711.95:545:45
2811.85:545:44
2911.85:555:43
3011.85:555:42

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4 kWh/m².

For context, solar energy here swings from a low near 3.63 kWh/m² to a high of 6.33 kWh/m² in April across the year — September's 4 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.0Moderate
24.0Bright
34.0Bright
44.0Bright
54.0Bright
64.0Bright
74.0Bright
84.0Bright
94.0Bright
104.0Bright
114.0Bright
124.0Bright
134.0Bright
144.0Bright
154.0Bright
164.0Bright
174.0Bright
184.0Bright
194.0Bright
204.0Bright
214.0Bright
224.0Bright
234.0Bright
244.0Bright
254.1Bright
264.1Bright
274.1Bright
284.1Bright
294.2Bright
304.2Bright
Planning a trip in September

Hazard calendar for Lahān

In seasonPeak

In September, Lahān sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

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

Is September a good time to visit Lahān?

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

3.2
Sightseeing
7th-best month of the year
4.7
Beach & pool
9th-best month of the year

September is a weaker month for outdoor sightseeing in Lahān.

What to pack for Lahān in September

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

In September, Lahān sees daytime highs around 31°C and nights near 25°C. Pack light clothes and rain gear. About 23 days see rain.

light clothesrain gear

UV index in Lahān in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

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

Air quality in Lahān 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 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
Location & terrain

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
September weather 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).