Nan weather in September

In September, Nan sees average daytime highs of 31°C and overnight lows near 24°C, with 221 mm of rain across 24.4 wet days and about 12.1 hours of daylight. It is the 8th-warmest and 3rd-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 7% 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 48 min by month's end. Set against the rest of the year, September is Nan's 9th-clearest and 11th-windiest month. For the whole year in context, see Nan's year-round climate.

Daytime high
31°
8th warmest
Overnight low
24°
8th coldest
Rainfall
221 mm
24.4 wet days
Daylight
12 h 06 min
6:08 AM – 6:14 PM
Cloud cover
82%
9th clearest
Wind
3 km/h
11th windiest
Solar energy
4.24 kWh/m²
Travel score
2.8
out of 10

Nan is town in Nan province, Thailand.

Air quality
High
PM2.5 29.5 µg/m³ · 2019

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 Nan reaches about 31°C in the afternoon and slips back to 24°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 29°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)
13124
23124
33124
43124
53124
63124
73124
83124
93124
103124
113124
123124
133124
143124
153124
163124
173124
183124
193124
203124
213124
223124
233124
243124
253124
263124
273124
283124
293124
303124

How September really feels in Nan

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.

Nan weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 16°152116.4
Feb33° / 17°81.211.44.7
Mar35° / 20°304.611.92.9
Apr36° / 24°7811.612.42.2
May34° / 25°16621.512.92.3
Jun32° / 25°19023.413.12.5
Jul31° / 25°27326.5132.6
Aug31° / 24°31228.112.62.6
Sep31° / 24°22124.412.12.8
Oct31° / 23°7413.811.64.1
Nov31° / 20°223.511.15.4
Dec29° / 17°141.710.96.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 7% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 9% of September, with mostly cloudy or overcast conditions the remaining 83%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1694
2694
3793
4793
5892
6892
7991
81090
91189
101288
111288
121288
131486
141486
151585
161684
171783
181783
191981
201981
212179
222179
232476
242476
252575
262773
272773
283070
293169
303268

Chance of precipitation in September

Any precipitation

Nan gets around 221 mm of rain over 24.4 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 88% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
188
288
388
488
587
687
787
886
986
1085
1185
1284
1384
1483
1582
1682
1781
1880
1979
2079
2178
2277
2376
2475
2575
2674
2773
2872
2970
3069

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 56% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
103367
203367
303466
403466
503565
603565
703565
803664
903664
1003664
1103763
1203862
1303862
1403961
1514059
1614158
1714257
1814356
1914455
2014554
2114653
2214851
2314949
2415247
2515445
2625543
2725741
2825939
2926137
3026335

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 4 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
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 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 6:05 AM to 6:11 AM, and sunset from 6:28 PM to 6:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:056:28
212.46:066:27
312.36:066:26
412.36:066:25
512.36:066:24
612.36:066:23
712.36:066:23
812.36:076:22
912.26:076:21
1012.26:076:20
1112.26:076:19
1212.26:076:18
1312.26:086:17
1412.16:086:16
1512.16:086:15
1612.16:086:14
1712.16:086:13
1812.16:086:13
1912.16:096:12
2012.06:096:11
2112.06:096:10
2212.06:096:09
2312.06:096:08
2412.06:106:07
2511.96:106:06
2611.96:106:05
2711.96:106:04
2811.96:106:03
2911.96:116:03
3011.86:116:02

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.24 kWh/m².

For context, solar energy here swings from a low near 3.85 kWh/m² to a high of 6.22 kWh/m² in April across the year — September's 4.24 kWh/m² sits near the bottom.

024151015202530
Solar energy (kWh/m²)Level
14.0Bright
24.0Bright
34.0Bright
44.0Bright
54.1Bright
64.1Bright
74.1Bright
84.1Bright
94.1Bright
104.1Bright
114.1Bright
124.1Bright
134.2Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.3Bright
194.3Bright
204.3Bright
214.3Bright
224.3Bright
234.4Bright
244.4Bright
254.4Bright
264.5Bright
274.5Bright
284.5Bright
294.5Bright
304.5Bright
Planning a trip in September

Hazard calendar for Nan

In seasonPeak

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

Nan'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 Nan?

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

2.8
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 Nan.

What to pack for Nan in September

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

In September, Nan sees daytime highs around 31°C and nights near 24°C. Pack light clothes and rain gear. About 24 days see rain.

light clothesrain gear

UV index in Nan 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 Nan peaks around August 12 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 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 12UV 13Dec 17UV 7
UV index (midday)Level
Jan8Very high
Feb9Very high
Mar9Very high
Apr10Very high
May11Extreme
Jun13Extreme
Jul13Extreme
Aug13Extreme
Sep11Extreme
Oct10Very high
Nov8Very high
Dec7High

Air quality in Nan 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 Nan is worst in March — around 71 µg/m³ PM2.5 (unhealthy), about 4.2× the cleanest month (September, 17 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Nan's WHO annual average of 29.5 µg/m³.

020406080JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyModerateMar 2270 µg/m³Sep 1517 µg/m³
PM2.5 (µg/m³)Level
Jan27Moderate
Feb39Poor
Mar71Unhealthy
Apr65Unhealthy
May28Moderate
Jun17Moderate
Jul17Moderate
Aug17Moderate
Sep17Moderate
Oct17Moderate
Nov18Moderate
Dec21Moderate
Location & terrain

Where is Nan?

Nan sits at 18.8°N, 100.8°E, 205 m above sea level, in Thailand. The nearest listed city is Dok Kham Tai, 93 km away.

Dok Kham TaiPhraePhayaoDen ChaiLampangUttaraditChiang RaiBan Houakhoua

Topography around Nan

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

Within 3 km, the terrain around Nan has only modest variations in elevation — a maximum elevation change of 61 m around an average of 208 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 478 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,915 m.

The land around Nan is covered by trees (39%), artificial surfaces (28%) and cropland (21%) within 3 km, trees (76%) within 16 km, and trees (87%) within 80 km.

3 km
61 m
16 km
478 m
80 km
1,915 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Dok Kham Tai 93 km · Phrae 98 km · Phayao 105 km · Den Chai 117 km · Lampang 146 km · Uttaradit 148 km · Chiang Rai 160 km · Ban Houakhoua 166 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 Nan (18.7838°, 100.779°, elevation 205 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).