Nanjing weather in September

In September, Nanjing sees average daytime highs of 27°C and overnight lows near 20°C, with 81 mm of rain across 8.4 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 29°C in the first days to 25°C by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Nanjing's 5th-clearest and 6th-windiest month. For the whole year in context, see Nanjing's year-round climate.

Daytime high
27°
4th warmest
Overnight low
20°
9th coldest
Rainfall
81 mm
8.4 wet days
Daylight
12 h 12 min
5:53 AM – 6:05 PM
Cloud cover
58%
5th clearest
Wind
10 km/h
6th windiest
Solar energy
4.15 kWh/m²
Travel score
6.4
out of 10

Nanjing is capital city of Jiangsu Province, China, former capital of the Republic of China and China's Ming dynasty.

Air quality
Very high
PM2.5 44.7 µg/m³ · 2018
Density
1,414/km²
people per km²
Founded
~494 BCE

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 29°C in the first days to 25°C by the end.

A typical September day in Nanjing reaches about 27°C in the afternoon and slips back to 20°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 31°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12923
22923
32923
42922
52922
62922
72922
82822
92822
102821
112821
122821
132821
142821
152720
162720
172720
182720
192720
202720
212719
222619
232619
242619
252619
262618
272618
282618
292518
302518

How September really feels in Nanjing

Once humidity and wind are folded in, September averages 2 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
2
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.

Nanjing weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 558210.11.0
Feb10° / 558.31.310.82.2
Mar15° / 80100.411.84.3
Apr21° / 12°949.1012.86.4
May26° / 17°1219.8013.66.6
Jun29° / 22°22211.9014.15.2
Jul32° / 25°21015.1013.93.5
Aug31° / 25°17414.4013.23.9
Sep27° / 20°818.4012.26.4
Oct22° / 14°546.3011.27.4
Nov16° / 536.80.110.45.5
Dec10° / 345.60.49.92.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% 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 53%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14357
24555
34456
44555
54555
64654
74654
84654
94654
104654
114654
124654
134852
144753
154852
164852
174852
184852
194951
204951
214951
224951
234951
244951
254951
265050
274951
285050
295050
305050

Chance of precipitation in September

Any precipitation

Nanjing gets around 81 mm of rain over 8.4 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 29% and peaks near 38% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
138
237
336
435
534
633
733
832
931
1031
1130
1230
1329
1429
1529
1628
1728
1827
1926
2026
2125
2225
2324
2424
2524
2624
2723
2823
2923
3023

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 60% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1017293527
2028313425
3029333323
40211343221
50212353119
60313363018
70314372916
81415382914
91516382813
101617382712
111718372611
121819372510
13292136249
142102235238
153122334227
163132433216
173142632196
184162730185
194172829175
205182928164
216193027144
226203126134
237213225123
248213324113
2510223323102
261123332292
271323332182
281424332171
291625322071
301725321961

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 10 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3010calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 60 minutes over September. Sunrise moves from 5:44 AM to 6:03 AM, and sunset from 6:25 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:446:25
212.75:456:24
312.65:456:23
412.65:466:21
512.65:466:20
612.55:476:19
712.55:486:17
812.55:486:16
912.45:496:15
1012.45:506:13
1112.45:506:12
1212.35:516:11
1312.35:526:09
1412.35:526:08
1512.25:536:06
1612.25:536:05
1712.25:546:04
1812.15:556:02
1912.15:556:01
2012.15:565:59
2112.05:575:58
2212.05:575:57
2312.05:585:55
2411.95:595:54
2511.95:595:53
2611.96:005:51
2711.86:015:50
2811.86:015:49
2911.86:025:47
3011.76:035:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.15 kWh/m².

For context, solar energy here swings from a low near 2.53 kWh/m² to a high of 5.28 kWh/m² in May across the year — September's 4.15 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.3Bright
44.3Bright
54.3Bright
64.3Bright
74.3Bright
84.2Bright
94.2Bright
104.2Bright
114.2Bright
124.2Bright
134.2Bright
144.1Bright
154.1Bright
164.1Bright
174.1Bright
184.1Bright
194.1Bright
204.1Bright
214.1Bright
224.0Bright
234.0Bright
244.0Bright
254.0Bright
264.0Moderate
274.0Moderate
284.0Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Hazard calendar for Nanjing

In seasonPeak

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

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

Nanjing's rainy season runs May–August, when most of the year's rain falls.

Pacific typhoon
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Nanjing?

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

6.4
Sightseeing
3rd-best month of the year
6.8
Beach & pool
1st-best month of the year

September is a reasonable time to visit Nanjing for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Nanjing in September

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

In September, Nanjing sees daytime highs around 27°C and nights near 20°C. Pack light clothes. Worth having: rain gear. About 8 days see rain.

light clothesrain gear

UV index in Nanjing in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Nanjing peaks around July 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 21UV 9Dec 17UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr6High
May7High
Jun6High
Jul9Very high
Aug8Very high
Sep9Very high
Oct5Moderate
Nov3Moderate
Dec3Moderate

Air quality in Nanjing 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 Nanjing is worst in January — around 59 µg/m³ PM2.5 (unhealthy), about 2.0× the cleanest month (August, 29 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Nanjing's WHO annual average of 44.7 µg/m³.

020406080JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorModeratePoorUnhealthyJan 1059 µg/m³Aug 929 µg/m³
PM2.5 (µg/m³)Level
Jan59Unhealthy
Feb55Poor
Mar53Poor
Apr48Poor
May42Poor
Jun36Poor
Jul29Moderate
Aug29Moderate
Sep35Poor
Oct44Poor
Nov49Poor
Dec58Unhealthy
Location & terrain

Where is Nanjing?

Nanjing sits at 32.1°N, 118.8°E, 22 m above sea level, in China. The nearest listed city is Wuxi, 153 km away.

NingboWuhan

Topography around Nanjing

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

Within 3 km, the terrain around Nanjing has only modest variations in elevation — a maximum elevation change of 59 m around an average of 15 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 514 m; within 80 km, large variations in elevation — a maximum elevation change of 611 m.

The land around Nanjing is covered by artificial surfaces (66%) and trees (22%) within 3 km, artificial surfaces (46%) and trees (28%) within 16 km, and cropland (51%) and trees (28%) within 80 km.

3 km
59 m
16 km
514 m
80 km
611 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Wuxi 153 km · Suzhou 192 km · Pingyao 216 km · Hangzhou 237 km · Tunxi 265 km · Shanghai 270 km · Ningbo 359 km · Wuhan 459 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 Nanjing (32.0617°, 118.7778°, elevation 22 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). 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).