Nam Som weather in September

In September, Nam Som sees average daytime highs of 31°C and overnight lows near 24°C, with 266 mm of rain across 24.4 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 31°C through the month. The sky is clear or mostly clear about 10% 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 Nam Som's 9th-clearest and 12th-windiest month. For the whole year in context, see Nam Som's year-round climate.

Daytime high: 31°; 6th warmest
Overnight low: 24°; 8th coldest
Rainfall: 266 mm; 24.4 wet days
Daylight: 12 h 06 min; 6:03 AM – 6:09 PM
Cloud cover: 80%; 9th clearest
Wind: 5 km/h; 12th windiest
Solar energy: 4.39 kWh/m²
Travel score: 2.8; out of 10

← August Nam Som year-round climate October →Best places to visit in September

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

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 Nam Som 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.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31
Avg low (°C)	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24

	Avg high (°C)	Avg low (°C)
1	31	25
2	31	25
3	31	25
4	31	25
5	31	25
6	31	25
7	31	25
8	31	25
9	31	25
10	31	25
11	31	25
12	31	25
13	31	25
14	31	25
15	31	25
16	31	24
17	31	24
18	31	24
19	31	24
20	31	24
21	31	24
22	31	24
23	31	24
24	31	24
25	31	24
26	31	24
27	31	24
28	31	24
29	31	24
30	31	24

How September really feels in Nam Som

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

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Nam Som 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.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	29° / 17°	10	1.6	11.1	7.1
Feb	31° / 18°	14	2.4	11.4	5.5
Mar	34° / 22°	39	6.9	11.9	3.6
Apr	35° / 24°	78	12.8	12.4	2.5
May	33° / 25°	236	23.1	12.8	2.3
Jun	32° / 25°	231	22.8	13	2.4
Jul	32° / 25°	268	24.9	13	2.5
Aug	31° / 25°	326	26.3	12.6	2.6
Sep	31° / 24°	266	24.4	12.1	2.8
Oct	31° / 23°	105	12.3	11.6	4.4
Nov	30° / 20°	23	2.9	11.2	6.1
Dec	28° / 17°	9	1.3	11	7.7

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 10% of September, with mostly cloudy or overcast conditions the remaining 79%. Skies tend to open up as the month goes on.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	9	9	9	9	9	11	11	11	12	12	13	15	15	16	17	19	19	22	23	24	27	28	29	32	32	34	35	37	38	39
Cloudier (%)	91	91	91	91	91	89	89	89	88	88	87	85	85	84	83	81	81	78	77	76	73	72	71	68	68	66	65	63	62	61

	Clearer (%)	Cloudier (%)
1	9	91
2	9	91
3	9	91
4	9	91
5	9	91
6	11	89
7	11	89
8	11	89
9	12	88
10	12	88
11	13	87
12	15	85
13	15	85
14	16	84
15	17	83
16	19	81
17	19	81
18	22	78
19	23	77
20	24	76
21	27	73
22	28	72
23	29	71
24	32	68
25	32	68
26	34	66
27	35	65
28	37	63
29	38	62
30	39	61

Chance of precipitation in September

Any precipitation

Nam Som gets around 266 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 89% on the wettest days. The odds ease toward the end of the month.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	89	89	89	89	89	89	89	88	88	87	87	86	86	85	84	83	82	81	80	79	77	76	75	73	72	70	69	67	66	64

	Rain chance (%)
1	89
2	89
3	89
4	89
5	89
6	89
7	89
8	88
9	88
10	87
11	87
12	86
13	86
14	85
15	84
16	83
17	82
18	81
19	80
20	79
21	77
22	76
23	75
24	73
25	72
26	70
27	69
28	67
29	66
30	64

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 62% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Muggy (%)	0	0	0	0	0	0	0	0	0	1	1	1	1	1	2	2	2	2	3	3	3	3	4	4	4	4	5	5	6	6
Oppressive (%)	23	23	24	25	26	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	44	45	47	48	50	52	53	54
Miserable (%)	77	77	76	75	74	74	73	72	71	69	68	67	66	65	63	62	61	60	58	57	56	55	52	51	49	47	45	43	41	40

	Muggy (%)	Oppressive (%)	Miserable (%)
1	0	23	77
2	0	23	77
3	0	24	76
4	0	25	75
5	0	26	74
6	0	26	74
7	0	27	73
8	0	28	72
9	0	29	71
10	1	30	69
11	1	31	68
12	1	32	67
13	1	33	66
14	1	34	65
15	2	35	63
16	2	36	62
17	2	37	61
18	2	38	60
19	3	39	58
20	3	40	57
21	3	41	56
22	3	42	55
23	4	44	52
24	4	45	51
25	4	47	49
26	4	48	47
27	5	50	45
28	5	52	43
29	6	53	41
30	6	54	40

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.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (km/h)	Feels
1	5	calm
2	5	calm
3	5	calm
4	5	calm
5	5	calm
6	5	calm
7	5	calm
8	5	calm
9	5	calm
10	5	calm
11	5	calm
12	5	calm
13	5	calm
14	5	calm
15	5	calm
16	5	calm
17	5	calm
18	5	calm
19	5	calm
20	5	calm
21	5	calm
22	5	calm
23	5	calm
24	5	calm
25	5	calm
26	5	calm
27	5	calm
28	5	calm
29	5	calm
30	5	calm

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 6:00 AM to 6:05 AM, and sunset from 6:22 PM to 5:56 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	12.4	12.3	12.3	12.3	12.3	12.3	12.3	12.2	12.2	12.2	12.2	12.2	12.2	12.1	12.1	12.1	12.1	12.1	12.0	12.0	12.0	12.0	12.0	12.0	11.9	11.9	11.9	11.9	11.9	11.9
Sunrise (AM)	6:00	6:01	6:01	6:01	6:01	6:01	6:01	6:01	6:02	6:02	6:02	6:02	6:02	6:02	6:02	6:03	6:03	6:03	6:03	6:03	6:03	6:03	6:04	6:04	6:04	6:04	6:04	6:04	6:05	6:05
Sunset (PM)	6:22	6:21	6:20	6:19	6:18	6:17	6:16	6:16	6:15	6:14	6:13	6:12	6:11	6:10	6:09	6:09	6:08	6:07	6:06	6:05	6:04	6:03	6:02	6:01	6:01	6:00	5:59	5:58	5:57	5:56

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.4	6:00	6:22
2	12.3	6:01	6:21
3	12.3	6:01	6:20
4	12.3	6:01	6:19
5	12.3	6:01	6:18
6	12.3	6:01	6:17
7	12.3	6:01	6:16
8	12.2	6:01	6:16
9	12.2	6:02	6:15
10	12.2	6:02	6:14
11	12.2	6:02	6:13
12	12.2	6:02	6:12
13	12.2	6:02	6:11
14	12.1	6:02	6:10
15	12.1	6:02	6:09
16	12.1	6:03	6:09
17	12.1	6:03	6:08
18	12.1	6:03	6:07
19	12.0	6:03	6:06
20	12.0	6:03	6:05
21	12.0	6:03	6:04
22	12.0	6:03	6:03
23	12.0	6:04	6:02
24	12.0	6:04	6:01
25	11.9	6:04	6:01
26	11.9	6:04	6:00
27	11.9	6:04	5:59
28	11.9	6:04	5:58
29	11.9	6:05	5:57
30	11.9	6:05	5:56

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.39 kWh/m².

For context, solar energy here swings from a low near 4.2 kWh/m² to a high of 6.03 kWh/m² in April across the year — September's 4.39 kWh/m² sits near the bottom.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	4.2	4.2	4.2	4.2	4.2	4.2	4.3	4.3	4.3	4.3	4.3	4.3	4.3	4.3	4.3	4.3	4.4	4.4	4.4	4.4	4.5	4.5	4.5	4.5	4.5	4.5	4.6	4.6	4.6	4.6
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	4.2	Bright
2	4.2	Bright
3	4.2	Bright
4	4.2	Bright
5	4.2	Bright
6	4.2	Bright
7	4.3	Bright
8	4.3	Bright
9	4.3	Bright
10	4.3	Bright
11	4.3	Bright
12	4.3	Bright
13	4.3	Bright
14	4.3	Bright
15	4.3	Bright
16	4.3	Bright
17	4.4	Bright
18	4.4	Bright
19	4.4	Bright
20	4.4	Bright
21	4.5	Bright
22	4.5	Bright
23	4.5	Bright
24	4.5	Bright
25	4.5	Bright
26	4.5	Bright
27	4.6	Bright
28	4.6	Bright
29	4.6	Bright
30	4.6	Bright

Planning a trip in September

Hazard calendar for Nam Som

In seasonPeak

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

Nam Som'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 Nam Som?

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

8th-best month of the year

September is a weaker month for outdoor sightseeing in Nam Som.

What to pack for Nam Som in September

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

In September, Nam Som 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 Nam Som 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 Nam Som peaks around August 12 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 8 (very high).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	9	10	12	11	11	13	13	13	11	10	8	8
Level	Very high	Very high	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Very high	Very high

	UV index (midday)	Level
Jan	9	Very high
Feb	10	Very high
Mar	12	Extreme
Apr	11	Extreme
May	11	Extreme
Jun	13	Extreme
Jul	13	Extreme
Aug	13	Extreme
Sep	11	Extreme
Oct	10	Extreme
Nov	8	Very high
Dec	8	Very high

Air quality in Nam Som 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 Nam Som is worst in April — around 122 µg/m³ PM2.5 (unhealthy), about 8.3× the cleanest month (November, 15 µg/m³).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	22	37	108	122	28	16	15	16	15	16	15	17
Level	Moderate	Poor	Unhealthy	Unhealthy	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	PM2.5 (µg/m³)	Level
Jan	22	Moderate
Feb	37	Poor
Mar	108	Unhealthy
Apr	122	Unhealthy
May	28	Moderate
Jun	16	Moderate
Jul	15	Moderate
Aug	16	Moderate
Sep	15	Moderate
Oct	16	Moderate
Nov	15	Moderate
Dec	17	Moderate

Location & terrain

Where is Nam Som?

Nam Som sits at 17.8°N, 102.2°E, 231 m above sea level, in Thailand. The nearest listed city is Tha Bo, 42 km away.

Topography around Nam Som

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

Within 3 km, the terrain around Nam Som has only modest variations in elevation — a maximum elevation change of 156 m around an average of 227 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 559 m; within 80 km, large variations in elevation — a maximum elevation change of 951 m.

The land around Nam Som is covered by trees (51%) and cropland (36%) within 3 km, trees (66%) and cropland (28%) within 16 km, and trees (59%) and cropland (34%) within 80 km.

3 km

156 m

trees 51%

16 km

559 m

trees 66%

80 km

951 m

trees 59%

treesgrasslandcroplandartificial surfaceswater

← August Nam Som year-round climate October →Best places to visit in September

September weather nearby: Tha Bo 42 km · Vientiane 49 km · Na Klang 52 km · Kut Chap 55 km · Erawan 58 km · Loei 58 km · Nong Khai 60 km · Nong Bua Lamphu 68 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

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 Nam Som (17.7704°, 102.1895°, elevation 231 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).

	Avg high (°C)	Avg low (°C)
1	31	25
2	31	25
3	31	25
4	31	25
5	31	25
6	31	25
7	31	25
8	31	25
9	31	25
10	31	25
11	31	25
12	31	25
13	31	25
14	31	25
15	31	25
16	31	24
17	31	24
18	31	24
19	31	24
20	31	24
21	31	24
22	31	24
23	31	24
24	31	24
25	31	24
26	31	24
27	31	24
28	31	24
29	31	24
30	31	24

	Clearer (%)	Cloudier (%)
1	9	91
2	9	91
3	9	91
4	9	91
5	9	91
6	11	89
7	11	89
8	11	89
9	12	88
10	12	88
11	13	87
12	15	85
13	15	85
14	16	84
15	17	83
16	19	81
17	19	81
18	22	78
19	23	77
20	24	76
21	27	73
22	28	72
23	29	71
24	32	68
25	32	68
26	34	66
27	35	65
28	37	63
29	38	62
30	39	61

	Rain chance (%)
1	89
2	89
3	89
4	89
5	89
6	89
7	89
8	88
9	88
10	87
11	87
12	86
13	86
14	85
15	84
16	83
17	82
18	81
19	80
20	79
21	77
22	76
23	75
24	73
25	72
26	70
27	69
28	67
29	66
30	64

	Muggy (%)	Oppressive (%)	Miserable (%)
1	0	23	77
2	0	23	77
3	0	24	76
4	0	25	75
5	0	26	74
6	0	26	74
7	0	27	73
8	0	28	72
9	0	29	71
10	1	30	69
11	1	31	68
12	1	32	67
13	1	33	66
14	1	34	65
15	2	35	63
16	2	36	62
17	2	37	61
18	2	38	60
19	3	39	58
20	3	40	57
21	3	41	56
22	3	42	55
23	4	44	52
24	4	45	51
25	4	47	49
26	4	48	47
27	5	50	45
28	5	52	43
29	6	53	41
30	6	54	40

	Avg high (°C)	Avg low (°C)
1	31	25
2	31	25
3	31	25
4	31	25
5	31	25
6	31	25
7	31	25
8	31	25
9	31	25
10	31	25
11	31	25
12	31	25
13	31	25
14	31	25
15	31	25
16	31	24
17	31	24
18	31	24
19	31	24
20	31	24
21	31	24
22	31	24
23	31	24
24	31	24
25	31	24
26	31	24
27	31	24
28	31	24
29	31	24
30	31	24

	Clearer (%)	Cloudier (%)
1	9	91
2	9	91
3	9	91
4	9	91
5	9	91
6	11	89
7	11	89
8	11	89
9	12	88
10	12	88
11	13	87
12	15	85
13	15	85
14	16	84
15	17	83
16	19	81
17	19	81
18	22	78
19	23	77
20	24	76
21	27	73
22	28	72
23	29	71
24	32	68
25	32	68
26	34	66
27	35	65
28	37	63
29	38	62
30	39	61

	Rain chance (%)
1	89
2	89
3	89
4	89
5	89
6	89
7	89
8	88
9	88
10	87
11	87
12	86
13	86
14	85
15	84
16	83
17	82
18	81
19	80
20	79
21	77
22	76
23	75
24	73
25	72
26	70
27	69
28	67
29	66
30	64

	Muggy (%)	Oppressive (%)	Miserable (%)
1	0	23	77
2	0	23	77
3	0	24	76
4	0	25	75
5	0	26	74
6	0	26	74
7	0	27	73
8	0	28	72
9	0	29	71
10	1	30	69
11	1	31	68
12	1	32	67
13	1	33	66
14	1	34	65
15	2	35	63
16	2	36	62
17	2	37	61
18	2	38	60
19	3	39	58
20	3	40	57
21	3	41	56
22	3	42	55
23	4	44	52
24	4	45	51
25	4	47	49
26	4	48	47
27	5	50	45
28	5	52	43
29	6	53	41
30	6	54	40

	Avg high (°C)	Avg low (°C)
1	31	25
2	31	25
3	31	25
4	31	25
5	31	25
6	31	25
7	31	25
8	31	25
9	31	25
10	31	25
11	31	25
12	31	25
13	31	25
14	31	25
15	31	25
16	31	24
17	31	24
18	31	24
19	31	24
20	31	24
21	31	24
22	31	24
23	31	24
24	31	24
25	31	24
26	31	24
27	31	24
28	31	24
29	31	24
30	31	24

	Clearer (%)	Cloudier (%)
1	9	91
2	9	91
3	9	91
4	9	91
5	9	91
6	11	89
7	11	89
8	11	89
9	12	88
10	12	88
11	13	87
12	15	85
13	15	85
14	16	84
15	17	83
16	19	81
17	19	81
18	22	78
19	23	77
20	24	76
21	27	73
22	28	72
23	29	71
24	32	68
25	32	68
26	34	66
27	35	65
28	37	63
29	38	62
30	39	61

	Rain chance (%)
1	89
2	89
3	89
4	89
5	89
6	89
7	89
8	88
9	88
10	87
11	87
12	86
13	86
14	85
15	84
16	83
17	82
18	81
19	80
20	79
21	77
22	76
23	75
24	73
25	72
26	70
27	69
28	67
29	66
30	64

	Muggy (%)	Oppressive (%)	Miserable (%)
1	0	23	77
2	0	23	77
3	0	24	76
4	0	25	75
5	0	26	74
6	0	26	74
7	0	27	73
8	0	28	72
9	0	29	71
10	1	30	69
11	1	31	68
12	1	32	67
13	1	33	66
14	1	34	65
15	2	35	63
16	2	36	62
17	2	37	61
18	2	38	60
19	3	39	58
20	3	40	57
21	3	41	56
22	3	42	55
23	4	44	52
24	4	45	51
25	4	47	49
26	4	48	47
27	5	50	45
28	5	52	43
29	6	53	41
30	6	54	40