Nong Khai weather in September

In September, Nong Khai sees average daytime highs of 31°C and overnight lows near 25°C, with 297 mm of rain across 24.5 wet days and about 12.1 hours of daylight. It is the 6th-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 12% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 24 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Nong Khai's 9th-clearest and 12th-windiest month. For the whole year in context, see Nong Khai's year-round climate.

Daytime high
31°
6th warmest
Overnight low
25°
8th coldest
Rainfall
297 mm
24.5 wet days
Daylight
12 h 06 min
6:00 AM – 6:06 PM
Cloud cover
79%
9th clearest
Wind
5 km/h
12th windiest
Solar energy
4.4 kWh/m²
Travel score
2.7
out of 10

Nong Khai is town in Nong Khai province, Thailand.

Density
2,042/km²
people per km²

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 Nong Khai 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 29°C and 34°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
173225
183225
193225
203225
213225
223225
233225
243225
253225
263225
273225
283225
293225
303225

How September really feels in Nong Khai

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
19 feel dangerously hot (≥ 39°C)
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.

Nong Khai weather by month

How September compares with the rest of the year at a glance. September is the 6th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 17°91.6117.0
Feb31° / 19°14211.45.7
Mar34° / 22°315.611.93.8
Apr35° / 25°6610.612.42.6
May33° / 25°24522.612.82.3
Jun32° / 26°31425.513.12.3
Jul32° / 26°37927.4132.4
Aug31° / 25°40627.912.62.4
Sep31° / 25°29724.512.12.7
Oct31° / 24°9311.511.64.2
Nov31° / 21°193.111.25.8
Dec29° / 18°81.310.97.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 12% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 12% 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 (%)
11288
21288
31387
41387
51387
61486
71585
81585
91585
101585
111882
121882
131981
142080
152179
162476
172476
182674
192773
202971
213169
223169
233268
243565
253664
263763
273961
284060
294159
304357

Chance of precipitation in September

Any precipitation

Nong Khai gets around 297 mm of rain over 24.5 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 81% and peaks near 92% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
192
292
392
492
592
692
791
891
991
1090
1189
1288
1387
1486
1585
1684
1782
1881
1979
2078
2176
2274
2372
2471
2569
2667
2766
2864
2962
3061

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 86% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
10397
20397
30397
40397
50496
60496
70595
80595
90694
100694
110793
121891
131990
1411089
1511188
1611287
1721385
1821385
1921484
2021583
2121682
2221880
2331978
2432077
2532275
2632374
2732473
2842670
2942769
3042967

Wind in September

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

Across September, daily wind ranges from about 5 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
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
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 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 30 minutes over September. Sunrise moves from 5:58 AM to 6:03 AM, and sunset from 6:19 PM to 5:54 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:586:19
212.35:586:19
312.35:586:18
412.35:596:17
512.35:596:16
612.35:596:15
712.35:596:14
812.25:596:13
912.25:596:13
1012.25:596:12
1112.26:006:11
1212.26:006:10
1312.26:006:09
1412.16:006:08
1512.16:006:07
1612.16:006:06
1712.16:016:05
1812.16:016:05
1912.06:016:04
2012.06:016:03
2112.06:016:02
2212.06:016:01
2312.06:016:00
2412.06:025:59
2511.96:025:58
2611.96:025:57
2711.96:025:57
2811.96:025:56
2911.96:025:55
3011.96:035:54

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.4 kWh/m².

For context, solar energy here swings from a low near 4.13 kWh/m² to a high of 6.04 kWh/m² in April across the year — September's 4.4 kWh/m² sits near the bottom.

024151015202530
Solar energy (kWh/m²)Level
14.2Bright
24.2Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.2Bright
84.2Bright
94.2Bright
104.2Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.4Bright
174.4Bright
184.4Bright
194.5Bright
204.5Bright
214.5Bright
224.5Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
Planning a trip in September

Hazard calendar for Nong Khai

In seasonPeak

In September, Nong Khai sits inside its pacific typhoon and monsoon season. The full year is below, with each hazard's peak months called out.

Nong Khai sits in the Pacific typhoon belt; the season peaks July–October.

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

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

Is September a good time to visit Nong Khai?

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

2.7
Sightseeing
7th-best month of the year
4.2
Beach & pool
9th-best month of the year

September is a weaker month for outdoor sightseeing in Nong Khai.

What to pack for Nong Khai in September

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

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

light clothesrain gear

UV index in Nong Khai 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 Nong Khai peaks around August 11 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 7 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highAug 11UV 13Dec 15UV 7
UV index (midday)Level
Jan8Very high
Feb10Very high
Mar12Extreme
Apr10Extreme
May11Extreme
Jun13Extreme
Jul13Extreme
Aug13Extreme
Sep11Extreme
Oct10Extreme
Nov8Very high
Dec7Very high

Air quality in Nong Khai 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 Nong Khai is worst in March — around 77 µg/m³ PM2.5 (unhealthy), about 3.4× the cleanest month (July, 23 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyModerateMar 2376 µg/m³Jul 2123 µg/m³
PM2.5 (µg/m³)Level
Jan31Moderate
Feb44Poor
Mar77Unhealthy
Apr73Unhealthy
May32Moderate
Jun24Moderate
Jul23Moderate
Aug23Moderate
Sep24Moderate
Oct26Moderate
Nov25Moderate
Dec26Moderate
Location & terrain

Where is Nong Khai?

Nong Khai sits at 17.9°N, 102.7°E, 168 m above sea level, in Thailand. The nearest listed city is Tha Bo, 17 km away.

Topography around Nong Khai

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

Within 3 km, the terrain around Nong Khai has only modest variations in elevation — a maximum elevation change of 31 m around an average of 168 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 47 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,489 m.

The land around Nong Khai is covered by trees (34%) and artificial surfaces (32%) within 3 km, cropland (44%) and trees (31%) within 16 km, and trees (51%) and cropland (41%) within 80 km.

3 km
31 m
16 km
47 m
80 km
1,489 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Tha Bo 17 km · Vientiane 18 km · Phon Charoen 48 km · Udon Thani 52 km · Kut Chap 54 km · Ban Dung 58 km · Nam Som 60 km · Nong Bua Lamphu 82 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 Nong Khai (17.8785°, 102.742°, elevation 168 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).