Pai weather in September

In September, Pai sees average daytime highs of 29°C and overnight lows near 21°C, with 248 mm of rain across 25.6 wet days and about 12.1 hours of daylight. It is the 6th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 3% of the time in September, and the air most often feels oppressive.

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 Pai's 9th-clearest and 10th-windiest month. For the whole year in context, see Pai's year-round climate.

Daytime high
29°
6th warmest
Overnight low
21°
8th coldest
Rainfall
248 mm
25.6 wet days
Daylight
12 h 06 min
6:17 AM – 6:24 PM
Cloud cover
85%
9th clearest
Wind
4 km/h
10th windiest
Solar energy
4.2 kWh/m²
Travel score
3.4
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical September day in Pai reaches about 29°C in the afternoon and slips back to 21°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 31°C. Set against its neighbours, September runs on par with August and on par with October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12921
22921
32921
42921
52921
62921
72921
82921
92921
102921
112921
122921
132921
142921
152921
162921
172921
182921
192921
202921
212921
222921
232921
242921
252921
262921
272921
282921
292921
302921

How September really feels in Pai

Once humidity and wind are folded in, September averages 0 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
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Pai weather by month

How September compares with the rest of the year at a glance. September is the 6th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 12°162.4118.2
Feb30° / 13°71.411.36.6
Mar32° / 16°213.311.94.8
Apr33° / 20°607.712.43.7
May31° / 21°19320.712.93.3
Jun29° / 22°22125.413.13.1
Jul29° / 22°28727.713.13.2
Aug28° / 21°3212912.73.1
Sep29° / 21°24825.612.13.4
Oct28° / 20°11617.611.64.9
Nov27° / 17°376.611.17.2
Dec26° / 14°163.210.98.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 3% 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 88%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1496
2595
3694
4694
5694
6694
7694
8793
9892
10892
11892
12892
13892
14892
15991
161189
171189
181189
191288
201486
211585
221684
231783
241783
251981
262080
272179
282377
292476
302674

Chance of precipitation in September

Any precipitation

Pai gets around 248 mm of rain over 25.6 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 85% and peaks near 90% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
190
290
390
490
590
690
790
890
990
1090
1189
1289
1388
1488
1587
1686
1786
1885
1984
2083
2182
2282
2381
2480
2579
2679
2778
2878
2977
3077

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 70% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1002476
2002476
3002476
4002476
5002476
6002377
7002377
8002377
9002377
10002377
11002377
12002476
13002476
14002575
15002674
16002773
17002872
18002971
19003070
20003169
21003268
22003367
23013465
24013663
25013861
26013960
27014158
28024256
29124453
30124552

Wind in September

Winds average 4 km/h in September.

Across September, daily wind ranges from about 4 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
84calm
94calm
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
264calm
274calm
284calm
294calm
304calm

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 6:14 AM to 6:20 AM, and sunset from 6:38 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:146:38
212.46:156:37
312.46:156:36
412.36:156:35
512.36:156:34
612.36:156:33
712.36:166:32
812.36:166:31
912.26:166:30
1012.26:166:29
1112.26:166:28
1212.26:176:28
1312.26:176:27
1412.16:176:26
1512.16:176:25
1612.16:176:24
1712.16:176:23
1812.16:186:22
1912.16:186:21
2012.06:186:20
2112.06:186:19
2212.06:186:18
2312.06:196:17
2412.06:196:16
2511.96:196:15
2611.96:196:15
2711.96:206:14
2811.96:206:13
2911.96:206:12
3011.86:206:11

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.2 kWh/m².

For context, solar energy here swings from a low near 3.74 kWh/m² to a high of 6.38 kWh/m² in April across the year — September's 4.2 kWh/m² sits near the bottom.

012345151015202530
Solar energy (kWh/m²)Level
14.0Bright
24.0Bright
34.0Bright
44.0Bright
54.0Bright
64.0Bright
74.0Bright
84.1Bright
94.1Bright
104.1Bright
114.1Bright
124.1Bright
134.1Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.2Bright
194.3Bright
204.3Bright
214.3Bright
224.3Bright
234.3Bright
244.4Bright
254.4Bright
264.4Bright
274.4Bright
284.4Bright
294.4Bright
304.5Bright
Planning a trip in September

Hazard calendar for Pai

In seasonPeak

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

Pai'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 Pai?

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

3.4
Sightseeing
8th-best month of the year
4.2
Beach & pool
9th-best month of the year

September is a weaker month for outdoor sightseeing in Pai.

What to pack for Pai in September

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

In September, Pai sees daytime highs around 29°C and nights near 21°C. Pack light clothes and rain gear. About 26 days see rain.

light clothesrain gear

UV index in Pai in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Pai peaks around August 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 14Dec 22UV 7
UV index (midday)Level
Jan8Very high
Feb10Very high
Mar10Very high
Apr10Extreme
May12Extreme
Jun12Extreme
Jul13Extreme
Aug14Extreme
Sep12Extreme
Oct11Extreme
Nov9Very high
Dec7Very high

Air quality in Pai 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 Pai is worst in March — around 90 µg/m³ PM2.5 (unhealthy), about 9.6× the cleanest month (October, 9 µg/m³).

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

0306090JanFebMarAprMayJunJulAugSepOctNovDecModerateUnhealthyModerateGoodMar 1985 µg/m³Oct 249 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb35Moderate
Mar90Unhealthy
Apr57Unhealthy
May20Moderate
Jun11Good
Jul10Good
Aug10Good
Sep10Good
Oct9Good
Nov9Good
Dec11Good
Location & terrain

Where is Pai?

Pai sits at 19.4°N, 98.4°E, 0 m above sea level, in Thailand. The nearest listed city is Chiang Mai, 86 km away.

San Pa TongSan KamphaengLamphunPa SangLoikawPhayao

Topography around Pai

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

Within 3 km, the terrain around Pai has significant variations in elevation — a maximum elevation change of 444 m around an average of 563 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,543 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,997 m.

The land around Pai is covered by trees (48%), grassland (23%) and cropland (21%) within 3 km, trees (86%) within 16 km, and trees (91%) within 80 km.

3 km
444 m
16 km
1,543 m
80 km
1,997 m
treesgrasslandcroplandartificial surfaces
September weather nearby: Chiang Mai 86 km · Hang Dong 90 km · San Pa Tong 95 km · San Kamphaeng 99 km · Lamphun 105 km · Pa Sang 107 km · Loikaw 134 km · Phayao 152 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 Pai (19.3617°, 98.4397°, elevation 0 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).