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Nanjing weather by month: averages, rainfall & climate trends

Nanjing swings through a wide annual range, with 25.5°C between the monthly means of its warmest and coldest months. Rainfall leans toward the stretch from May to September. Nanjing weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+3.0°Chigh well above average

25° / 17°Today
22° / 13°Average
see today in detail →

How it's changed

+1.0°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4936frost days a year now (2016–2025) · 51 in the 1940sfrost days a year · 51 in the 1940s80days above 30°C a year now (2016–2025) · 65 in the 1940sdays above 30°C · 65 in the 1940s+1.0°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 46 mmhigh 7°low −1°February, rain 60 mmhigh 9°low 1°March, rain 87 mmhigh 14°low 6°April, rain 107 mmhigh 20°low 12°May, rain 139 mmhigh 25°low 17°June, rain 235 mmhigh 28°low 21°July, rain 228 mmhigh 32°low 25°August, rain 146 mmhigh 31°low 25°September, rain 113 mmhigh 27°low 20°October, rain 58 mmhigh 22°low 14°November, rain 50 mmhigh 16°low 7°December, rain 33 mmhigh 9°low 1°wettest month June, 235 mm · 1,301 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Overcast

Right now

21.7°

23°feels like
83%humidity
19°dew point
12 km/hfrom NW
UV index0.0
sunrise06:10sunset17:29day length11h 19m
SunOvercast25°17°
MonShowers17°15°
TueOvercast19°15°
WedClear17°10°
ThuOvercast18°10°
FriOvercast19°13°
SatOvercast22°14°

On this date: October 17

Today (forecast)
25° / 17°
Average for October 17
22° / 13°

High well above average · +3.0°C

  • Record high: 28.0° · 1997
  • Record low: 6.7° · 1963
  • One year ago: 26° / 17°

Every October 17 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 17 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Nanjing is sampled from the ECMWF ERA5 reanalysis at 32.06°N, 118.78°E, with daily records since 1940.

Coordinates
32.06°N, 118.78°E
Time zone
Asia/Shanghai
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

19 of the last 31 days were warmer than the historical average for that date. Average difference: +1.0°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The year peaks in July, at around 31.6°C by mid-afternoon, with nights around 25.4°C. Roughly 80 days a year now top 30°C. In January, the coolest month, afternoons reach about 6.7°C and nights dip to −1.2°C.

In total, Nanjing averages about 1,301 mm of precipitation a year; June is usually the wettest month (235 mm) and December the driest (33 mm).

Over the full record (since 1940), the annual mean temperature in Nanjing has risen by 1.0°C between its first decade and its last. Where the first decade averaged 50 frost days a year, the recent one saw about 35.

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 26°C. Wettest month: June (~235 mm). Whole year averages ~1,301 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 99 rainy days a year: most in July (~14), fewest in December (~4).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Nanjing month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January6.7°−1.2°46 mm610.1 h21.7° (1950)−22.9° (1955)
February8.8°0.9°60 mm710.9 h27.8° (2009)−15.8° (1957)
March13.9°5.7°87 mm911.8 h34.7° (2025)−5.5° (1957)
April20.1°11.7°107 mm912.8 h33.7° (2023)−0.2° (1962)
May25.0°16.9°139 mm913.6 h35.6° (2019)7.0° (1984)
June28.4°21.5°235 mm1114.1 h37.6° (2005)12.6° (1969)
July31.6°25.4°228 mm1413.9 h38.4° (2017)17.6° (2015)
August31.5°24.9°146 mm1213.2 h39.6° (1946)17.3° (1968)
September27.0°20.1°113 mm912.2 h39.6° (1946)9.7° (1957)
October21.9°13.7°58 mm511.2 h38.9° (2022)2.3° (1978)
November15.8°7.4°50 mm510.3 h29.6° (1979)−10.2° (1979)
December9.4°1.0°33 mm49.9 h23.4° (1953)−13.4° (1966)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.0°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.15°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Mar–May is warming fastest: +0.23°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 65.0 early in the record → 79.9 recently. Frost days: 51 → 36.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 1946, all-time low in 1955: 39.6°C / −22.9°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~1,301 mm/year on average. Last decade: −3% vs that average. Long-term trend: −15 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Nanjing

Which is the warmest month in Nanjing?
On long-term average, the warmest month in Nanjing is July (mean daily temperature of about 28.2°C) and the coolest is January (about 2.7°C).
How does today's temperature in Nanjing compare to the historical average?
On October 17, 2026, Nanjing is forecast to reach a high of 24.7°C and a low of 16.7°C. The long-term average for this date (the full record since 1940) is a high of 21.7°C and a low of 13.3°C, so today's high is 3.0°C warmer than that average.
How much has Nanjing warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Nanjing is about 1.0°C warmer.
How much does it rain in Nanjing?
Nanjing receives about 1,301 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Nanjing?
Over the full record (since 1940), the annual mean temperature in Nanjing is about 16.0°C. The warmest month is July and the coolest is January.
What are the average temperatures in Nanjing by month?
Average daily highs and lows for each month in Nanjing (°C, full record since 1940): January 7°/−1°, February 9°/1°, March 14°/6°, April 20°/12°, May 25°/17°, June 28°/21°, July 32°/25°, August 31°/25°, September 27°/20°, October 22°/14°, November 16°/7°, December 9°/1°.
What is the weather like in Nanjing in summer?
June to August is summer in Nanjing, and it is wet and hot. Daytime highs sit at 28–32°C and nights at 21–25°C; July is the warmest month. Rain falls off from 235 mm in June to 146 mm in August. It is the wettest season of the year.
What is the weather like in Nanjing in winter?
Winter in Nanjing (December to February) is on the cool side. Afternoons run 7–9°C and nights −1 to 1°C; January is the coldest month. Rain rises from 33 mm on 4 days in December to 60 mm on 7 days in February. No season is drier.
What is the weather like in Nanjing in spring?
March to May is spring in Nanjing, and it is wet and mild. March starts at 14°C by day and 6°C at night; by May it is 25°C and 17°C. Rain picks up through the season, 87 mm in March to 139 mm in May.
What is the weather like in Nanjing in autumn?
In autumn, September through November, Nanjing is mild. September is still 27°C by day and 20°C at night; by November it is down to 16°C and 7°C. Rain eases through the season: 9 rainy days and 113 mm in September, 5 days and 50 mm in November.
How many days a year does it rain in Nanjing?
On long-term average, Nanjing has about 99 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,301 mm.

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