Ilām weather in September

In September, Ilām sees average daytime highs of 24°C and overnight lows near 18°C, with 396 mm of rain across 28.3 wet days and about 12.2 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 24°C through the month. The sky is clear or mostly clear about 6% of the time in September, and the air most often feels muggy.

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 Ilām's 9th-clearest and 11th-windiest month. For the whole year in context, see Ilām's year-round climate.

Daytime high
24°
5th warmest
Overnight low
18°
9th coldest
Rainfall
396 mm
28.3 wet days
Daylight
12 h 12 min
5:43 AM – 5:52 PM
Cloud cover
79%
9th clearest
Wind
3 km/h
11th windiest
Solar energy
3.79 kWh/m²
Travel score
3.9
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 24°C through the month.

A typical September day in Ilām reaches about 24°C in the afternoon and slips back to 18°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 26°C. Set against its neighbours, September runs on par with August and about 1°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12519
22519
32519
42519
52519
62519
72519
82519
92519
102519
112519
122418
132418
142418
152418
162418
172418
182418
192418
202418
212418
222418
232418
242418
252417
262417
272417
282417
292417
302417

Ilām weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan15° / 296.510.55.2
Feb17° / 5611.2115.4
Mar21° / 10°1001711.85.6
Apr24° / 13°16321.812.65.1
May25° / 16°28828.513.34.1
Jun25° / 19°52629.513.73.6
Jul24° / 20°82530.913.53.4
Aug25° / 19°56630.6133.5
Sep24° / 18°39628.312.23.9
Oct23° / 14°1351811.45.8
Nov20° / 10°277.110.77.0
Dec17° / 153.410.36.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 6% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 81%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1892
2892
3991
4991
51090
61189
71288
81387
91486
101585
111684
121684
131783
141783
151783
161981
171981
181981
191981
202179
212179
222377
232575
242773
252773
262971
273070
283268
293565
303763

Chance of precipitation in September

Any precipitation

Ilām gets around 396 mm of rain over 28.3 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 93% and peaks near 97% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
197
297
397
497
597
696
796
896
995
1095
1194
1294
1394
1494
1594
1694
1794
1894
1994
2094
2193
2293
2392
2492
2591
2690
2789
2888
2987
3085

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 78% of days. Sticky, muggy-or-worse air turns up on roughly 78% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
103961
204951
304951
405941
506931
607921
708920
809910
9010900
10011890
11012880
12013870
13014860
14015850
15016840
16117820
17119800
18120790
19122770
20124750
21127720
22129700
23232660
24235630
25237610
26341560
27344530
28347500
29450460
30553420

Wind in September

Winds average 3 km/h in September.

Across September, daily wind ranges from about 3 km/h on the calmest days to 3 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
13calm
23calm
33calm
43calm
53calm
63calm
73calm
83calm
93calm
103calm
113calm
123calm
133calm
143calm
153calm
163calm
173calm
183calm
193calm
203calm
213calm
223calm
233calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm

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 5:36 AM to 5:49 AM, and sunset from 6:10 PM to 5:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.65:366:10
212.55:376:09
312.55:376:08
412.55:386:06
512.55:386:05
612.45:386:04
712.45:396:03
812.45:396:02
912.35:406:01
1012.35:405:59
1112.35:415:58
1212.35:415:57
1312.25:425:56
1412.25:425:55
1512.25:425:54
1612.25:435:52
1712.15:435:51
1812.15:445:50
1912.15:445:49
2012.05:455:48
2112.05:455:46
2212.05:465:45
2312.05:465:44
2411.95:475:43
2511.95:475:42
2611.95:475:40
2711.95:485:39
2811.85:485:38
2911.85:495:37
3011.85:495:36

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.79 kWh/m².

For context, solar energy here swings from a low near 3.29 kWh/m² to a high of 5.7 kWh/m² in April across the year — September's 3.79 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
13.7Moderate
23.7Moderate
33.7Moderate
43.7Moderate
53.7Moderate
63.7Moderate
73.7Moderate
83.7Moderate
93.8Moderate
103.8Moderate
113.8Moderate
123.8Moderate
133.8Moderate
143.8Moderate
153.8Moderate
163.8Moderate
173.8Moderate
183.8Moderate
193.8Moderate
203.9Moderate
213.9Moderate
223.9Moderate
233.9Moderate
243.9Moderate
253.9Moderate
263.9Moderate
274.0Moderate
284.0Moderate
294.0Bright
304.0Bright
Planning a trip in September

Hazard calendar for Ilām

In seasonPeak

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

Ilām'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 Ilām?

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

3.9
Sightseeing
9th-best month of the year
3.4
Beach & pool
5th-best month of the year

September is a weaker month for outdoor sightseeing in Ilām.

What to pack for Ilām in September

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

In September, Ilām sees daytime highs around 24°C and nights near 18°C. Pack rain gear. Worth having: light clothes. About 28 days see rain.

rain gearlight clothes

UV index in Ilām in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ilām peaks around July 18 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 4 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeModerateJul 18UV 12Jan 1UV 4
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar9Very high
Apr8Very high
May9Very high
Jun9Very high
Jul13Extreme
Aug10Extreme
Sep11Extreme
Oct6High
Nov4Moderate
Dec4Moderate

Air quality in Ilām 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 Ilām is worst in January — around 111 µg/m³ PM2.5 (unhealthy), about 4.6× the cleanest month (July, 24 µg/m³).

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

0306090120JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorModeratePoorUnhealthyJan 18111 µg/m³Jul 1925 µg/m³
PM2.5 (µg/m³)Level
Jan111Unhealthy
Feb107Unhealthy
Mar92Unhealthy
Apr74Unhealthy
May52Poor
Jun37Poor
Jul24Moderate
Aug31Moderate
Sep40Poor
Oct59Unhealthy
Nov81Unhealthy
Dec104Unhealthy
Location & terrain

Where is Ilām?

Ilām sits at 26.9°N, 87.9°E, 1,218 m above sea level, in Nepal. The nearest listed city is Darjeeling, 36 km away.

DhankutāDharānĪṭahari̇̄BiratnagarInaruwaKhā̃dbāri̇̄

Topography around Ilām

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

Within 3 km, the terrain around Ilām has large variations in elevation — a maximum elevation change of 966 m around an average of 897 m above sea level; within 16 km, extreme variations in elevation — a maximum elevation change of 2,582 m; within 80 km, extreme variations in elevation — a maximum elevation change of 7,186 m.

The land around Ilām is covered by trees (88%) within 3 km, trees (92%) within 16 km, and trees (66%) and cropland (25%) within 80 km.

3 km
966 m
16 km
2,582 m
80 km
7,186 m
treesgrasslandcroplandartificial surfacesbare terrainsnow and icewatermoss and lichen
September weather nearby: Darjeeling 36 km · Bhadrapur 44 km · Dhankutā 60 km · Dharān 65 km · Īṭahari̇̄ 70 km · Biratnagar 83 km · Inaruwa 84 km · Khā̃dbāri̇̄ 88 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 Ilām (26.9094°, 87.9282°, elevation 1,218 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).