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Suzhou weather by month: averages, rainfall & climate trends

Threaded with canals that earned it the nickname Venice of the East, Suzhou owes its watery character to the mild, rain-fed flatlands of the Yangtze delta. Suzhou weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+7.4°Chigh well above average

29° / 20°Today
21° / 16°Average
see today in detail →

How it's changed

+1.1°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4912frost days a year now (2016–2025) · 26 in the 1940sfrost days a year · 26 in the 1940s70days above 30°C a year now (2016–2025) · 54 in the 1940sdays above 30°C · 54 in the 1940s+1.1°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 63 mmhigh 7°low 1°February, rain 84 mmhigh 8°low 3°March, rain 120 mmhigh 13°low 7°April, rain 137 mmhigh 19°low 13°May, rain 165 mmhigh 24°low 18°June, rain 281 mmhigh 27°low 22°July, rain 184 mmhigh 32°low 27°August, rain 144 mmhigh 31°low 26°September, rain 132 mmhigh 27°low 22°October, rain 69 mmhigh 22°low 16°November, rain 62 mmhigh 16°low 10°December, rain 49 mmhigh 9°low 4°wettest month June, 281 mm · 1,488 mm a yearsee month by month →

Right now

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

Right now

27.7°

31°feels like
66%humidity
21°dew point
9 km/hfrom W
UV index4.7
sunrise06:02sunset17:23day length11h 21m
TodayOvercast29°20°
MonOvercast22°18°
TueOvercast26°18°
WedMostly clear21°15°
ThuOvercast19°12°
FriOvercast21°14°
SatLight rain21°17°

On this date: October 18

Today (forecast)
29° / 20°
Average for October 18
21° / 16°

High well above average · +7.4°C

  • Record high: 28.0° · 2024
  • Record low: 10.5° · 1963
  • One year ago: 23° / 18°

Every October 18 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 18 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 Suzhou is sampled from the ECMWF ERA5 reanalysis at 31.30°N, 120.60°E, with daily records since 1940.

Coordinates
31.30°N, 120.60°E
Time zone
Asia/Shanghai
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

25 of the last 31 days were warmer than the historical average for that date. Average difference: +1.7°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

Suzhou lies in Jiangsu province in eastern China, on the flat, low-lying Lake Tai plain of the Yangtze River Delta, with Lake Tai to the southwest and the Yangtze itself to the north. The climate is humid subtropical (Köppen Cfa), with four distinct seasons: muggy summer heat gives way to chilly, grey, damp winters and the occasional snow. Winter cold rides in on northwesterly winds from Siberia that can push temperatures below freezing, while southerly winds drive the strongest summer heat.

In late spring and early summer the meiyu, or plum rain, sets in as humid Pacific air collides with cooler air from inland along a stalled front over the Yangtze region; the persistent heavy rain it brings can cause flooding across the delta's dense network of canals and waterways. Summer's other face is heat: southerly flow can lift temperatures to punishing levels, as it did during the hot spell of early August 2013, made harder to bear by the region's heavy humidity.

July brings the year's peak warmth, with afternoons typically reaching 31.6°C and nights around 26.6°C. Roughly 70 days a year now top 30°C. The coolest month is January, when afternoons reach about 6.6°C and overnight lows sit around 1.3°C.

In total, Suzhou averages about 1,488 mm of precipitation a year; June is usually the wettest month (281 mm) and December the driest (49 mm).

The record here starts in 1940, and since then the annual mean in Suzhou has climbed 1.1°C from the first ten years to the last ten. Frost days have thinned out, from around 25 a year in the first decade to about 12 now.

Sources:en.wikipedia.orgen.wikipedia.orgcma.gov.cn

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 25°C. Wettest month: June (~281 mm). Whole year averages ~1,488 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 112 rainy days a year: most in June (~13), fewest in December (~5).

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.

Suzhou 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
January6.6°1.3°63 mm710.2 h19.1° (1950)−8.7° (1955)
February8.3°2.9°84 mm810.9 h24.1° (2009)−9.2° (1969)
March13.0°7.1°120 mm1111.8 h31.1° (2025)−3.1° (1958)
April19.1°12.9°137 mm1012.8 h31.4° (2005)2.8° (1962)
May24.0°18.0°165 mm1113.6 h35.5° (2018)10.0° (1974)
June27.4°22.3°281 mm1314.0 h36.8° (1946)14.7° (1954)
July31.6°26.6°184 mm1213.8 h38.4° (2017)18.2° (2015)
August31.2°26.2°144 mm1213.1 h38.8° (2013)20.0° (1993)
September26.8°22.0°132 mm1012.2 h36.9° (1946)14.0° (1957)
October21.5°16.2°69 mm611.2 h35.3° (2022)5.7° (1958)
November15.6°10.2°62 mm610.4 h28.0° (2023)−4.1° (1966)
December9.1°3.7°49 mm510.0 h20.6° (1968)−6.5° (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 +1.1°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: +0.22°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: 54.4 early in the record → 70.4 recently. Frost days: 26 → 12.

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 2013, all-time low in 1969: 38.8°C / −9.2°C.

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

Annual rainfall

~1,488 mm/year on average. Last decade: −1% vs that average. Long-term trend: −2 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 Suzhou

Which is the warmest month in Suzhou?
On long-term average, the warmest month in Suzhou is July (mean daily temperature of about 28.9°C) and the coolest is January (about 4.1°C).
How does today's temperature in Suzhou compare to the historical average?
On October 18, 2026, Suzhou is forecast to reach a high of 28.7°C and a low of 19.5°C. The long-term average for this date (the full record since 1940) is a high of 21.3°C and a low of 15.7°C, so today's high is 7.4°C warmer than that average.
How much has Suzhou warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Suzhou is about 1.1°C warmer.
How much does it rain in Suzhou?
Suzhou receives about 1,488 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Suzhou?
Over the full record (since 1940), the annual mean temperature in Suzhou is about 16.8°C. The warmest month is July and the coolest is January.
What are the average temperatures in Suzhou by month?
Average daily highs and lows for each month in Suzhou (°C, full record since 1940): January 7°/1°, February 8°/3°, March 13°/7°, April 19°/13°, May 24°/18°, June 27°/22°, July 32°/27°, August 31°/26°, September 27°/22°, October 22°/16°, November 16°/10°, December 9°/4°.
What is the weather like in Suzhou in summer?
In summer, June through August, Suzhou is wet and hot. June starts at 27°C by day and 22°C at night; by August it is 31°C and 26°C. Rain eases through the season: 13 rainy days and 281 mm in June, 12 days and 144 mm in August. No season is wetter.
What is the weather like in Suzhou in winter?
December to February is winter in Suzhou, and it is on the cool side. Expect 7–9°C by day and 1–4°C at night, with January the coldest month. Rain rises from 49 mm on 5 days in December to 84 mm on 8 days in February. No season is drier.
What is the weather like in Suzhou in spring?
March to May is spring in Suzhou, and it is wet and mild. It warms from 13°C by day and 7°C at night in March to 24°C and 18°C in May. Rain falls on about 11 days a month, adding up to around 141 mm.
What is the weather like in Suzhou in autumn?
In autumn, September through November, Suzhou is mild. It cools from 27°C by day and 22°C at night in September to 16°C and 10°C in November. Rain falls off from 132 mm on 10 days in September to 62 mm on 6 days in November.
How many days a year does it rain in Suzhou?
On long-term average, Suzhou has about 112 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,488 mm.

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