Xam Nua weather in September

In September, Xam Nua sees average daytime highs of 26°C and overnight lows near 19°C, with 200 mm of rain across 21.5 wet days and about 12.1 hours of daylight. It is the 6th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 10% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 24 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Xam Nua's 9th-clearest and 12th-windiest month. For the whole year in context, see Xam Nua's year-round climate.

Daytime high
26°
6th warmest
Overnight low
19°
8th coldest
Rainfall
200 mm
21.5 wet days
Daylight
12 h 06 min
5:55 AM – 6:02 PM
Cloud cover
78%
9th clearest
Wind
5 km/h
12th windiest
Solar energy
4.31 kWh/m²
Travel score
4.6
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Xam Nua reaches about 26°C in the afternoon and slips back to 19°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 29°C. Set against its neighbours, September runs about 1°C cooler than August and about 2°C warmer than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12720
22720
32720
42720
52720
62720
72720
82720
92720
102720
112720
122720
132720
142720
152619
162619
172619
182619
192619
202619
212619
222619
232619
242619
252619
262619
272619
282619
292619
302618

Xam Nua weather by month

How September compares with the rest of the year at a glance. September is the 6th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan20° / 10°244.210.97.1
Feb22° / 12°173.711.37.7
Mar25° / 14°6310.211.96.9
Apr27° / 17°11317.412.55.4
May28° / 20°20923.6134.0
Jun29° / 21°21724.513.23.5
Jul28° / 21°27626.813.13.6
Aug27° / 20°31227.412.73.7
Sep26° / 19°20021.512.14.6
Oct24° / 17°9214.611.56.1
Nov22° / 14°317117.2
Dec20° / 11°183.610.87.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 10% 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 76%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11585
21585
31585
41585
51684
61783
71783
81882
91882
101882
111981
122080
132080
142179
152278
162476
172575
182575
192773
202872
213070
223070
233169
243268
253268
263268
273268
283367
293466
303466

Chance of precipitation in September

Any precipitation

Xam Nua gets around 200 mm of rain over 21.5 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 72% and peaks near 83% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
183
283
382
482
581
681
780
879
979
1078
1177
1276
1376
1475
1573
1672
1771
1870
1969
2068
2167
2266
2365
2464
2563
2662
2761
2860
2960
3059

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 74% of days. Sticky, muggy-or-worse air turns up on roughly 82% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
10028315
20028315
30038314
40138214
50148114
60148213
70158113
80268012
90268012
100278011
110378010
120387910
13039799
140410788
150411778
160512767
170513757
180515737
190616726
200617716
210618706
220719686
230720685
240822655
250823645
260924634
270925624
280926614
2911027593
3011028583

Wind in September

Winds average 5 km/h in September, the calmest month.

Across September, daily wind ranges from about 4 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 24 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 36 minutes over September. Sunrise moves from 5:51 AM to 5:58 AM, and sunset from 6:16 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:516:16
212.45:516:15
312.45:526:14
412.45:526:13
512.35:526:12
612.35:526:11
712.35:536:10
812.35:536:09
912.35:536:08
1012.25:536:07
1112.25:546:06
1212.25:546:05
1312.25:546:05
1412.25:546:04
1512.15:546:03
1612.15:556:02
1712.15:556:01
1812.15:556:00
1912.15:555:59
2012.05:565:58
2112.05:565:57
2212.05:565:56
2312.05:565:55
2412.05:575:54
2511.95:575:53
2611.95:575:52
2711.95:575:51
2811.95:585:50
2911.95:585:49
3011.85:585:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.31 kWh/m².

For context, solar energy here swings from a low near 3.3 kWh/m² to a high of 5.34 kWh/m² in April across the year — September's 4.31 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.3Bright
54.3Bright
64.3Bright
74.3Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.3Bright
174.3Bright
184.3Bright
194.3Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.3Bright
254.3Bright
264.3Bright
274.3Bright
284.2Bright
294.2Bright
304.2Bright
Planning a trip in September

Hazard calendar for Xam Nua

In seasonPeak

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

Xam Nua'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

Is September a good time to visit Xam Nua?

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

4.6
Sightseeing
8th-best month of the year
4.5
Beach & pool
7th-best month of the year

September is a reasonable time to visit Xam Nua for sightseeing.

What to pack for Xam Nua in September

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

In September, Xam Nua sees daytime highs around 26°C and nights near 19°C. Pack rain gear. Worth having: light clothes. About 22 days see rain.

rain gearlight clothes

UV index in Xam Nua in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Xam Nua peaks around August 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highExtremeVery highAug 12UV 14Dec 17UV 7
UV index (midday)Level
Jan8Very high
Feb10Very high
Mar10Extreme
Apr9Very high
May11Extreme
Jun14Extreme
Jul13Extreme
Aug14Extreme
Sep10Extreme
Oct10Very high
Nov8Very high
Dec7High

Air quality in Xam Nua 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 Xam Nua is worst in April — around 288 µg/m³ PM2.5 (very unhealthy), about 35.5× the cleanest month (August, 8 µg/m³).

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

0306090120150180210240270JanFebMarAprMayJunJulAugSepOctNovDecModerateUnhealthyVery unhealthyUnhealthyGoodModerateApr 15263 µg/m³Aug 128 µg/m³
PM2.5 (µg/m³)Level
Jan20Moderate
Feb28Moderate
Mar98Unhealthy
Apr288Very unhealthy
May64Unhealthy
Jun14Moderate
Jul9Good
Aug8Good
Sep11Good
Oct15Moderate
Nov15Moderate
Dec19Moderate
Location & terrain

Where is Xam Nua?

Xam Nua sits at 20.4°N, 104.0°E, 957 m above sea level, in Laos. The nearest listed city is Vieng Xai, 19 km away.

Sơn LaBản Na HỷThị Trấn Thuận ChâuÍt OngMuang PhônsavanNghĩa LộHòa Bình

Topography around Xam Nua

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

Within 3 km, the terrain around Xam Nua has significant variations in elevation — a maximum elevation change of 373 m around an average of 1,033 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,118 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,963 m.

The land around Xam Nua is covered by trees (65%) within 3 km, trees (83%) within 16 km, and trees (82%) within 80 km.

3 km
373 m
16 km
1,118 m
80 km
1,963 m
treesgrasslandcroplandartificial surfacesbare terrain
September weather nearby: Vieng Xai 19 km · Sơn La 102 km · Bản Na Hỷ 108 km · Thị Trấn Thuận Châu 119 km · Ít Ong 122 km · Muang Phônsavan 140 km · Nghĩa Lộ 140 km · Hòa Bình 142 km

Laos travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / C / E / F
230 V · 50 Hz
Prices
≈ 23% of US
price level, 2025
GDP per capita
$2,325
2025
Happiness
5.5 / 10
World Happiness, 2025
Safe drinking water
35%
of population, 2024
Road deaths
17.9
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
Low
EF EPI 461
Religion
Buddhist 65%none 31%other/not stated 2%Christian 2%

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 Xam Nua (20.4164°, 104.045°, elevation 957 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).