Serian weather in September

In September, Serian sees average daytime highs of 32°C and overnight lows near 23°C, with 193 mm of rain across 23.4 wet days and about 12 hours of daylight. It is the 6th-warmest and 9th-wettest month of the year here.

Day-to-day highs hold fairly steady near 32°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 hours at the start of September to 12 hours by month's end. Set against the rest of the year, September is Serian's 6th-clearest and 6th-windiest month. For the whole year in context, see Serian's year-round climate.

Daytime high
32°
6th warmest
Overnight low
23°
7th coldest
Rainfall
193 mm
23.4 wet days
Daylight
12 hours
6:32 AM – 6:32 PM
Cloud cover
85%
6th clearest
Wind
4 km/h
6th windiest
Solar energy
5.11 kWh/m²
Travel score
2.7
out of 10

Serian is town in Sarawak, Malaysia.

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 32°C through the month.

A typical September day in Serian reaches about 32°C in the afternoon and slips back to 23°C overnight — a 8°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)
13223
23223
33223
43223
53223
63223
73223
83223
93223
103223
113223
123223
133223
143223
153223
163223
173223
183223
193223
203223
213223
223223
233223
243223
253223
263223
273223
283223
293223
303223

How September really feels in Serian

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.

Serian weather by month

How September compares with the rest of the year at a glance. September is the 6th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 23°26827.711.92.8
Feb30° / 23°23123.2122.9
Mar31° / 23°22426.6122.6
Apr32° / 24°21826.9122.4
May32° / 24°19625.212.12.5
Jun32° / 24°1472012.13.0
Jul32° / 23°13018.212.13.2
Aug32° / 23°15019.7122.9
Sep32° / 23°19323.4122.7
Oct31° / 23°25327.8122.5
Nov31° / 23°26128.711.92.4
Dec31° / 23°29228.111.92.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% 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 90%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11288
21189
31189
41189
51189
61090
71090
81090
91090
101090
11991
121090
131090
141090
151090
161090
171090
181189
191090
201090
211090
221090
231090
241090
251090
261090
27991
28892
29892
30892

Chance of precipitation in September

Any precipitation

Serian gets around 193 mm of rain over 23.4 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 78% and peaks near 83% on the wettest days.

0%20%40%60%80%151015202530
Rain chance (%)
176
277
377
477
577
678
778
878
977
1077
1177
1277
1377
1477
1577
1677
1777
1877
1977
2077
2178
2278
2379
2479
2580
2680
2781
2882
2983
3083

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 69% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
107525
207426
307426
407327
507327
607228
707228
807228
917128
1017128
1117029
1217029
1317029
1407030
1506931
1606931
1706832
1806832
1906733
2006733
2106634
2206634
2306634
2406535
2506535
2606535
2706436
2806436
2906436
3006436

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 hours at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over September. Sunrise moves from 6:37 AM to 6:27 AM, and sunset from 6:38 PM to 6:27 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.06:376:38
212.06:366:38
312.06:366:37
412.06:366:37
512.06:366:37
612.06:356:36
712.06:356:36
812.06:356:35
912.06:346:35
1012.06:346:35
1112.06:346:34
1212.06:336:34
1312.06:336:33
1412.06:336:33
1512.06:326:33
1612.06:326:32
1712.06:326:32
1812.06:316:31
1912.06:316:31
2012.06:316:31
2112.06:306:30
2212.06:306:30
2312.06:306:29
2412.06:296:29
2512.06:296:29
2612.06:296:28
2712.06:286:28
2812.06:286:28
2912.06:286:27
3012.06:276:27

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.11 kWh/m².

For context, solar energy here swings from a low near 4.23 kWh/m² to a high of 5.24 kWh/m² in August across the year — September's 5.11 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.1Bright
45.1Bright
55.1Bright
65.1Bright
75.1Bright
85.1Bright
95.1Bright
105.1Bright
115.1Bright
125.1Bright
135.1Bright
145.1Bright
155.1Bright
165.2Bright
175.1Bright
185.1Bright
195.1Bright
205.1Bright
215.1Bright
225.1Bright
235.1Bright
245.1Bright
255.1Bright
265.1Bright
275.0Bright
285.0Bright
295.0Bright
305.0Bright
Planning a trip in September

Is September a good time to visit Serian?

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

2.7
Sightseeing
6th-best month of the year
4.2
Beach & pool
4th-best month of the year

September is a weaker month for outdoor sightseeing in Serian.

What to pack for Serian in September

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

In September, Serian sees daytime highs around 32°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 23 days see rain.

light clothesrain gearsun protection

Sea temperature near Serian in September

The nearest coast averages about 30°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 51 km away) is warmest in June at about 30°C and coldest in February near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Tropical
Feb28Tropical
Mar29Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep30Tropical
Oct30Tropical
Nov30Tropical
Dec29Tropical

UV index in Serian in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Serian peaks around February 18 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 13 at about 11 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 18UV 16Jul 13UV 11
UV index (midday)Level
Jan14Extreme
Feb16Extreme
Mar15Extreme
Apr15Extreme
May13Extreme
Jun11Extreme
Jul11Extreme
Aug13Extreme
Sep13Extreme
Oct14Extreme
Nov12Extreme
Dec11Extreme

Air quality in Serian 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 Serian is worst in August — around 36 µg/m³ PM2.5 (poor), about 3.2× the cleanest month (January, 11 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModeratePoorModerateAug 2336 µg/m³Jan 1611 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb12Moderate
Mar14Moderate
Apr15Moderate
May15Moderate
Jun15Moderate
Jul23Moderate
Aug36Poor
Sep36Poor
Oct21Moderate
Nov13Moderate
Dec12Moderate
Location & terrain

Where is Serian?

Serian sits at 1.2°N, 110.6°E, 20 m above sea level, in Malaysia. The nearest listed city is Tebedu, 27 km away.

Topography around Serian

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

Within 3 km, the terrain around Serian has significant variations in elevation — a maximum elevation change of 327 m around an average of 33 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 775 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,649 m.

The land around Serian is covered by trees (82%) within 3 km, trees (95%) within 16 km, and trees (83%) within 80 km.

3 km
327 m
16 km
775 m
80 km
1,649 m
treesgrasslandartificial surfacesbare terrainwatermangroves
September weather nearby: Tebedu 27 km · Siburan 29 km · Simunjan 32 km · Kuching 50 km · Bau 54 km · Lundu 97 km · Sri Aman 99 km · Saratok 106 km

Malaysia travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / G / M
230 V · 50 Hz
Prices
≈ 32% of US
price level, 2025
GDP per capita
$13,125
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
95%
of population, 2024
Homicide rate
0.7
per 100k, 2023
Road deaths
22.5
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 581
Religion
Muslim 64%Buddhist 19%Christian 9%Hindu 6%

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 Serian (1.1667°, 110.5667°, elevation 20 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).