Sanya weather in September

In September, Sanya sees average daytime highs of 29°C and overnight lows near 26°C, with 258 mm of rain across 22.3 wet days and about 12.1 hours of daylight. It is the 5th-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 19% 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 Sanya's 9th-clearest and 11th-windiest month. For the whole year in context, see Sanya's year-round climate.

Daytime high
29°
5th warmest
Overnight low
26°
8th coldest
Rainfall
258 mm
22.3 wet days
Daylight
12 h 06 min
6:33 AM – 6:39 PM
Cloud cover
74%
9th clearest
Wind
11 km/h
11th windiest
Solar energy
4.74 kWh/m²
Travel score
3.8
out of 10

Sanya is prefecture-level city in Hainan, China.

Air quality
Elevated
PM2.5 15.5 µg/m³ · 2018
Density
537/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 29°C through the month.

A typical September day in Sanya reaches about 29°C in the afternoon and slips back to 26°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 30°C. Set against its neighbours, September runs on par with August and about 1°C warmer than October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12926
22926
32926
42926
52926
62926
72926
82926
92926
102926
112926
122926
132926
142926
152926
162926
172926
182926
192926
202926
212925
222925
232925
242925
252925
262925
272925
282925
292925
302925

How September really feels in Sanya

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.

Sanya weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan23° / 19°122.3118.2
Feb24° / 19°102.511.48.2
Mar25° / 22°183.811.97.9
Apr28° / 24°538.612.46.6
May29° / 26°1391912.84.3
Jun30° / 27°21222.213.13.4
Jul29° / 26°28023133.6
Aug29° / 26°26124.412.63.5
Sep29° / 26°25822.312.13.8
Oct28° / 24°1821411.65.7
Nov26° / 22°545.611.17.5
Dec24° / 19°26310.98.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 19% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 67%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12575
22575
32575
42575
52476
62575
72575
82575
92674
102773
112872
122971
132971
143070
153169
163268
173466
183565
193565
203664
213763
223763
233862
243961
253961
264060
274159
284258
294258
304456

Chance of precipitation in September

Any precipitation

Sanya gets around 258 mm of rain over 22.3 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 74% and peaks near 83% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
182
282
382
483
583
683
782
882
982
1081
1180
1280
1378
1477
1576
1675
1773
1872
1971
2070
2169
2268
2367
2466
2566
2665
2764
2864
2964
3063

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 65% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
101090
201189
301387
401486
501585
601684
701882
801981
912079
1012277
1112376
1212574
1312772
1412871
1523068
1623266
1723563
1823761
1923959
2024157
2124355
2224652
2324850
2425147
2525444
2635542
2735839
2845937
2946135
3056233

Wind in September

Winds average 11 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1712calm
1812calm
1912calm
2012calm
2112light breeze
2212light breeze
2312light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

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 6:31 AM to 6:36 AM, and sunset from 6:53 PM to 6:27 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:316:53
212.36:316:52
312.36:316:51
412.36:316:50
512.36:316:49
612.36:326:48
712.36:326:47
812.26:326:47
912.26:326:46
1012.26:326:45
1112.26:326:44
1212.26:336:43
1312.26:336:42
1412.16:336:41
1512.16:336:40
1612.16:336:39
1712.16:336:38
1812.16:346:38
1912.06:346:37
2012.06:346:36
2112.06:346:35
2212.06:346:34
2312.06:346:33
2412.06:356:32
2511.96:356:31
2611.96:356:30
2711.96:356:29
2811.96:356:29
2911.96:356:28
3011.96:366:27

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.74 kWh/m².

For context, solar energy here swings from a low near 3.79 kWh/m² to a high of 5.82 kWh/m² in April across the year — September's 4.74 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.9Bright
54.9Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.7Bright
164.7Bright
174.7Bright
184.7Bright
194.7Bright
204.7Bright
214.7Bright
224.7Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
Planning a trip in September

Hazard calendar for Sanya

In seasonPeak

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

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

Sanya's monsoon runs May–October, 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 Sanya?

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

3.8
Sightseeing
9th-best month of the year
4.9
Beach & pool
9th-best month of the year

September is a weaker month for outdoor sightseeing in Sanya.

What to pack for Sanya in September

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

In September, Sanya sees daytime highs around 29°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 22 days see rain.

light clothesrain gearsun protection

Sea temperature near Sanya in September

The nearest coast averages about 29°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 19 km away) is warmest in June at about 29°C and coldest in February near 23°C.

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

22°24°26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan23Refreshing
Feb23Refreshing
Mar24Warm
Apr26Warm
May28Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct28Warm
Nov26Warm
Dec25Warm

UV index in Sanya 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 Sanya peaks around August 11 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highHighAug 11UV 13Dec 16UV 7
UV index (midday)Level
Jan8Very high
Feb10Very high
Mar11Extreme
Apr11Extreme
May11Extreme
Jun12Extreme
Jul13Extreme
Aug13Extreme
Sep11Extreme
Oct10Very high
Nov8Very high
Dec7High

Air quality in Sanya 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 Sanya is worst in December — around 23 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (August, 11 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Sanya's WHO annual average of 15.5 µg/m³.

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateDec 1922 µg/m³Aug 1411 µg/m³
PM2.5 (µg/m³)Level
Jan20Moderate
Feb19Moderate
Mar17Moderate
Apr15Moderate
May11Good
Jun12Good
Jul11Good
Aug11Good
Sep11Good
Oct18Moderate
Nov18Moderate
Dec23Moderate
Location & terrain

Where is Sanya?

Sanya sits at 18.3°N, 109.5°E, 1 m above sea level, in China. The nearest listed city is An Hải, 278 km away.

Topography around Sanya

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

Within 3 km, the terrain around Sanya has only modest variations in elevation — a maximum elevation change of 203 m around an average of 24 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 610 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,775 m.

The land around Sanya is covered by trees (42%), artificial surfaces (32%) and water (22%) within 3 km, water (45%) and trees (41%) within 16 km, and trees (50%) and water (45%) within 80 km.

3 km
203 m
16 km
610 m
80 km
1,775 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: An Hải 278 km · Da Nang 279 km · Sơn Trà 279 km · Thanh Khê 280 km · Hòa Cường 283 km · Hương Thủy 284 km · Hue 285 km · Cẩm Lệ 285 km

China travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / I
220 V · 50 Hz
Prices
≈ 47% of US
price level, 2025
GDP per capita
$13,862
2025
Happiness
6.1 / 10
World Happiness, 2025
Homicide rate
0.5
per 100k, 2020
Road deaths
17.4
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 464
Religion
unaffiliated 52%folk religion 22%Buddhist 18%Christian 5%

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 Sanya (18.2543°, 109.5095°, elevation 1 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). 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).