Summer in Nanjing means long, hot, and humid days, all thanks to the East Asian monsoon. You’ll usually see average daytime highs around 32–33 °C (90–91 °F), but sometimes the heat pushes past 37 °C (99 °F).
Nights don’t cool off much, rarely dropping below 24 °C (75 °F), so the heat really sticks around.
Rain plays a big role in the season. Showers and thunderstorms pop up a lot, especially in June and July, when the city gets its heaviest rainfall of the year.
The air feels thick with humidity, making even moderate temperatures seem pretty intense.
Clouds and rain don’t block out the sun entirely though. You still get several hours of sunshine most days, and the long daylight lets you explore for longer.
If you know what to expect—heat, humidity, and sudden downpours—you can plan smarter and actually enjoy Nanjing’s summer.
Overview of Nanjing’s Summer Climate
Nanjing sits in eastern China, and the East Asian monsoon shapes its summers. High heat, strong humidity, and frequent rain make for some intense weather.
The patterns are pretty predictable, but they can feel overwhelming if you’re not used to them.
Geographical Location and Climate Type
Nanjing sits in Jiangsu Province, about 200 kilometers inland from the East China Sea, right along the lower Yangtze River.
This spot lets moist air masses sweep in during the summer monsoon, ramping up the humidity.
Under the Köppen system, the climate counts as humid subtropical (Cfa). So, summers are long, hot, and sticky, while winters are shorter and colder.
The Yangtze River valley holds onto heat and moisture, which makes summer even less comfortable.
On average, rainfall totals about 1,100–1,200 mm a year, and most of it falls from June to August.
Humidity usually sits above 70% during this stretch, so the air feels heavier than in drier inland cities.
Because of these traits, Nanjing ranks among the hotter and more humid cities in northern subtropical China.
Summer is easily the most extreme season here.
Seasonal Weather Patterns
From June through September, daily highs often land between 30–33 °C (86–91 °F).
July is the hottest month, with averages close to 28–29 °C (82–84 °F) and regular spikes over 37 °C (99 °F).
Nights don’t offer much relief, usually staying above 24 °C (75 °F). Locals call these “tropical nights.”
June and July bring the most rain, with thunderstorms and showers happening all the time.
July alone can see 200 mm or more of rain. That’s when the “plum rain” season hits, a stretch of damp, persistent weather tied to the monsoon.
Humidity stays high, usually between 70–77%. The heat and moisture together can make outdoor activities tough.
Sunshine averages 5–6.5 hours per day, but June is cloudier than the rest of the season.
Now and then, typhoons reach the region from late summer into early autumn.
They don’t hit as often as in coastal provinces, but when they do, Nanjing gets heavy rain and gusty winds, which can really mess with travel plans.
Average Summer Temperatures in Nanjing
Nanjing’s summer feels long, hot, and humid, with rising temperatures that barely let up at night.
You’ll get both intense daytime heat and warm evenings, especially in July and August.
Daytime and Nighttime Temperature Ranges
Daytime highs usually sit between 32°C and 35°C (90°F–95°F), but sometimes they edge closer to 37°C (99°F).
The sun and humidity combine to make the heat feel even stronger, especially downtown where all that concrete traps warmth.
Nights don’t cool off much. Lows hover around 25°C to 27°C (77°F–81°F) in July and August.
Even in June and September, nights rarely drop below 22°C (72°F).
Most homes, hotels, and public spaces rely on air conditioning to keep cool.
Since the city stays so warm overnight, you might notice it feels hot all the time.
If you’re outside for long stretches, the constant heat can get exhausting.
That’s why a lot of people plan their outings for the morning or evening.
Monthly Temperature Breakdown: June to September
Summer in Nanjing runs from June through September. Each month brings its own temperature changes:
| Month | Avg High | Avg Low | Notes |
|---|---|---|---|
| June | 30–32°C | 22–24°C | Start of humid season |
| July | 33–35°C | 25–27°C | Peak heat and humidity |
| August | 33–34°C | 25–26°C | Similar to July, slightly wetter |
| September | 28–30°C | 20–22°C | Cooling trend begins |
July is the hottest month, but August often feels just as uncomfortable because of the humidity and rain.
By late September, things start to cool down, though afternoons can still be pretty warm.
Record Highs and Notable Heatwaves
Nanjing is one of China’s “four furnace cities” for a reason—its extreme summer heat is notorious.
Record highs have hit 40°C (104°F) or more during severe heatwaves, and these stretches can last for days.
High pressure systems sometimes trap hot, moist air over the Yangtze River basin, kicking off these heatwaves.
Both day and night temperatures stay high, and humidity can soar past 75%.
If you visit during one of these spells, don’t expect much relief after dark.
It’s smart to stay hydrated, find shade, and shift your plans to avoid the worst of the heat.
Locals often change up their routines, heading out early or late to dodge the midday sun.
Rainfall and Humidity During Summer
Nanjing’s summer brings a lot of rain, high humidity, and long stretches of muggy weather.
You’ll probably deal with heavy downpours, sticky air, and days that feel hotter than the actual temperature.
Average Rainfall by Month
Rain peaks during the summer, with the most intense showers in June and July.
June averages about 170–190 mm of rain, and July often tops 200 mm, making it the wettest month.
August stays rainy, with around 120–150 mm. May and September get less, usually 90–100 mm.
Rain usually falls in short, intense bursts instead of steady drizzle.
Sudden thunderstorms, especially in the afternoon or evening, can quickly flood streets.
If you’re planning to be outside, stay flexible since heavy showers can show up out of nowhere.
| Month | Avg. Rainfall (mm) | Rainy Days (approx.) |
|---|---|---|
| June | 170–190 | 10–12 |
| July | 200+ | 12–13 |
| August | 120–150 | 9–11 |
Humidity Levels and Their Effects
Humidity stays high all summer, often above 75–80%.
July feels especially muggy, with an average relative humidity of about 81%, so the air gets pretty sticky.
This much moisture makes it harder for your body to cool itself by sweating.
Even when it’s just 30–32°C (86–90°F), the heat index can feel much higher.
High humidity can make indoor spaces uncomfortable too.
Air conditioning becomes a must, and you might notice condensation on windows or a damp feeling inside if airflow isn’t great.
Wearing lightweight, breathable clothes and drinking lots of water helps you deal with the sticky weather.
Rainy Season Duration and Characteristics
The rainy season in Nanjing usually runs from mid-June through late July, lining up with the East Asian monsoon.
Locals call it the plum rain season because it matches up with plum harvests.
During this stretch, you’ll see frequent showers, cloudy skies, and a good number of thunderstorms.
Rain often falls over several days in a row, leaving the city damp for a while.
August stays wet, but breaks of sunshine become more common between storms.
By September, autumn starts to take over, bringing less rain and a bit of drier air.
Sunshine Hours and Daylight
Nanjing gets a moderate amount of sunshine in summer, with July and August seeing the most.
Long daylight hours give you more time outside, but cloud cover and humidity often block out the direct sun.
Average Daily Sunshine Hours
You can expect 6 to 7.5 hours of direct sunshine per day in Nanjing during the summer.
July averages about 7 hours 27 minutes, and August is a touch higher at 7 hours 29 minutes.
June is a bit dimmer, with around 6 hours 24 minutes of sunshine daily.
Even though the days are long, high humidity and lots of clouds keep skies hazy more than half the time.
On average, about 46–57% of daylight hours from June to August are actually sunny.
So, nearly half the time, you’re looking at overcast or hazy skies.
If you want more reliable sunshine for outdoor plans, late summer is usually your best bet.
July and August tend to be brighter and a bit more predictable than early June.
Length of Daylight in Summer Months
Daylight peaks in June, with the sun up for 14 hours 11 minutes around the solstice.
July is close behind at about 14 hours, and August drops to 13 hours 17 minutes.
You get long evenings for sightseeing or just hanging out outside.
Even in September, daylight stays above 12 hours per day.
Long days plus moderate sunshine mean you have lots of usable daylight, but expect some clouds.
If you’re after the brightest skies, plan your outings for midday when the sun climbs 70–81° above the horizon in summer.
Extreme Weather and Typhoons
Nanjing’s summers bring more than just heat and humidity.
You’ll also need to watch out for strong storms.
Heavy rain linked to the East Asian monsoon and periods of extreme heat can feel even worse in the city’s dense environment.
Frequency of Typhoons and Storms
Nanjing isn’t on the coast, but typhoons from the western Pacific still affect the city.
These storms usually lose strength as they move inland, but they can bring heavy rainfall, gusty winds, and localized flooding.
The highest risk for typhoons is from July through September, when summer heat and the monsoon overlap.
During this window, you might get several days of rain in a row, sometimes over 150–200 mm in a single month. July is usually the wettest.
Storms can mess up transportation, especially trains and roads across Jiangsu Province.
Low-lying neighborhoods near the rivers are more likely to flood after big storms.
If you’re visiting, keep an eye on local weather reports and make sure you pack rain gear.
Heatwaves and Urban Heat Island Effects
People call Nanjing one of China’s “furnace cities.” It’s an inland city that regularly gets hammered by brutal summer heat. In July and August, daily highs usually hit 32°C (90°F), but during a heatwave, the temperature can shoot up even more and just linger there well into the night.
Tall buildings and crowded streets trap the heat, creating an urban heat island effect. The city stays several degrees warmer than the countryside nearby. Evenings rarely feel cool or refreshing, and sleeping can get uncomfortable when the heat just won’t let up.
Heatwaves worry a lot of people, especially older adults and travelers who aren’t used to muggy, subtropical weather. If you’re out and about, it’s smart to drink lots of water, avoid long stretches outside in the afternoon, and look for shade or air conditioning whenever you can.
Travel Advice for Visiting Nanjing in Summer
Summers in Nanjing drag on—hot, sticky, and humid. Early July usually brings plenty of rain, so you’ll want to think ahead about when to go, what to wear, and how to plan your days so you don’t melt.
Best Time to Visit Nanjing for Pleasant Weather
Summer stretches from June through September. The worst of the heat usually arrives in late July and early August, with highs that often hit 35–40°C (95–104°F). Humidity just makes everything feel even hotter, and the sky tends to stay cloudy.
If you’d rather not sweat buckets, try visiting in late May or early June, before the rainy season goes wild. September works too—temperatures start to dip, but you’ll still catch some summer scenery.
A lot of travelers say July is the toughest month. Early July often means days of rain, which can put a damper on outdoor plans. By late July, the heat ramps up and becomes relentless. If you can’t avoid July, keep your outdoor activities short and stick to indoor spots during the hottest times.
Recommended Clothing and Precautions
Pack light, airy clothes—cotton or linen shirts, shorts, and dresses will help you stay cool. Heavy fabrics just make you sweat more, so skip those if you can. A wide-brimmed hat, sunglasses, and sunscreen are must-haves to keep the sun off your skin.
You’ll want an umbrella or a light rain jacket, since summer showers pop up pretty often. Shoes that dry quickly are a lifesaver if you get caught in a downpour.
Heat exhaustion can sneak up on you in Nanjing’s summer. Drink water often, and try to skip alcohol or too much coffee, since those just make dehydration worse. Toss a few electrolyte tablets or a sports drink in your bag for long days outside.
If you have breathing or heart problems, try to stay inside during the hottest hours, usually from 11 a.m. to 3 p.m. Most public places, like museums and shopping malls, blast the air conditioning, so you can cool off there for a bit.
Tips for Outdoor Activities in Hot and Humid Conditions
Try planning outdoor sightseeing for the early morning or late afternoon. You’ll find temperatures are a bit more forgiving then.
Spots like the Sun Yat-sen Mausoleum or Purple Mountain feel way more enjoyable if you avoid the midday heat.
Bring a refillable water bottle—you’ll probably need to hydrate more than you think. Some parks and tourist areas offer refill stations, but honestly, I wouldn’t count on them being everywhere.
If you’re thinking about exploring the city on foot, break up your walk into shorter segments. Stick to shaded routes whenever you can, and duck indoors for a break when you need it.
For day trips outside the city, pick destinations with lots of shade or water, like Xuanwu Lake. Hanging out near the water or under trees makes the heat a lot more manageable.
Check the daily forecast before you head out. Rainstorms can pop up out of nowhere, so tossing an umbrella or poncho in your bag just makes life easier.