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Lanzhou weather by month: averages, rainfall & climate trends

Lanzhou swings through a wide annual range, with 26.4°C between the monthly means of its warmest and coldest months. Rainfall is strongly seasonal: the bulk of the year's rain falls between May and September. Lanzhou weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

−2.4°Chigh below average

15° / 4°Today
17° / 6°Average
see today in detail →

How it's changed

+1.3°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49117frost days a year now (2016–2025) · 127 in the 1940sfrost days a year · 127 in the 1940s58days above 30°C a year now (2016–2025) · 33 in the 1940sdays above 30°C · 33 in the 1940s+1.3°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 7 mmhigh 3°low −8°February, rain 10 mmhigh 7°low −5°March, rain 18 mmhigh 14°low 1°April, rain 29 mmhigh 20°low 7°May, rain 46 mmhigh 24°low 12°June, rain 64 mmhigh 28°low 16°July, rain 105 mmhigh 29°low 19°August, rain 107 mmhigh 28°low 18°September, rain 81 mmhigh 23°low 13°October, rain 43 mmhigh 17°low 6°November, rain 12 mmhigh 10°low −1°December, rain 5 mmhigh 5°low −6°wettest month August, 107 mm · 526 mm a yearsee month by month →

Right now

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

Right now

8.7°

8°feels like
91%humidity
7°dew point
3 km/hfrom S
UV index0.0
sunrise07:13sunset18:25day length11h 12m
TodayPartly cloudy15°4°
MonPartly cloudy15°7°
TueOvercast9°5°
WedMostly clear12°1°
ThuClear18°3°
FriClear19°3°
SatPartly cloudy13°5°

On this date: October 18

Today (forecast)
15° / 4°
Average for October 18
17° / 6°

High below average · −2.4°C

  • Record high: 25.4° · 2015
  • Record low: −1.9° · 1987
  • One year ago: 15° / 6°

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 Lanzhou is sampled from the ECMWF ERA5 reanalysis at 36.06°N, 103.84°E, with daily records since 1940.

Coordinates
36.06°N, 103.84°E
Time zone
Asia/Shanghai
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

18 of the last 31 days were warmer than the historical average for that date. Average difference: +0.3°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

July brings the year's peak warmth, with afternoons typically reaching 29.3°C and nights around 18.6°C. On about 30 nights a year, the temperature never drops below 20°C. At the other extreme, January brings afternoon highs of about 3.4°C and typical overnight lows of −8.2°C. Around 115 days a year dip below freezing.

Lanzhou picks up roughly 526 mm a year, with a peak of 107 mm in August and as little as 5 mm in December.

The record here starts in 1940, and since then the annual mean in Lanzhou has climbed 1.3°C from the first ten years to the last ten. The count of days past 30°C has risen from roughly 35 a year to 60 between the record's first and last decades.

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 26°C. Wettest month: August (~107 mm). Whole year averages ~526 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 63 rainy days a year: most in August (~11), fewest in December (almost none).

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.

Lanzhou 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
January3.4°−8.2°7 mm19.8 h20.2° (2014)−22.7° (2008)
February6.8°−5.1°10 mm110.7 h23.0° (2010)−20.7° (1945)
March13.5°0.8°18 mm311.7 h31.0° (2003)−12.4° (1988)
April19.7°7.1°29 mm412.9 h35.1° (1998)−10.3° (1969)
May24.2°12.4°46 mm613.9 h36.0° (2024)0.9° (1982)
June27.6°16.4°64 mm714.4 h38.3° (2022)6.6° (1970)
July29.3°18.6°105 mm1014.2 h41.6° (2010)11.4° (1983)
August27.9°17.5°107 mm1113.4 h38.4° (2011)10.2° (1988)
September22.8°12.9°81 mm1012.2 h35.2° (2023)2.8° (2015)
October17.3°6.5°43 mm611.1 h30.4° (2016)−5.5° (1986)
November10.4°−1.0°12 mm210.0 h23.4° (2018)−16.3° (1962)
December4.6°−6.0°5 mm09.6 h16.7° (2023)−19.8° (1975)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.3°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: +0.23°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: +0.25°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: 33.2 early in the record → 57.6 recently. Frost days: 127 → 117.

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 2010, all-time low in 2008: 41.6°C / −22.7°C.

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

Annual rainfall

~526 mm/year on average. Last decade: −6% vs that average. Long-term trend: −14 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 Lanzhou

Which is the warmest month in Lanzhou?
On long-term average, the warmest month in Lanzhou is July (mean daily temperature of about 23.7°C) and the coolest is January (about −2.7°C).
How does today's temperature in Lanzhou compare to the historical average?
On October 18, 2026, Lanzhou is forecast to reach a high of 14.6°C and a low of 3.8°C. The long-term average for this date (the full record since 1940) is a high of 17.0°C and a low of 6.4°C, so today's high is 2.4°C cooler than that average.
How much has Lanzhou warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Lanzhou is about 1.3°C warmer.
How much does it rain in Lanzhou?
Lanzhou receives about 526 mm of precipitation per year on long-term average, with August typically the wettest month.
What is the average temperature in Lanzhou?
Over the full record (since 1940), the annual mean temperature in Lanzhou is about 11.4°C. The warmest month is July and the coolest is January.
What are the average temperatures in Lanzhou by month?
Average daily highs and lows for each month in Lanzhou (°C, full record since 1940): January 3°/−8°, February 7°/−5°, March 14°/1°, April 20°/7°, May 24°/12°, June 28°/16°, July 29°/19°, August 28°/18°, September 23°/13°, October 17°/6°, November 10°/−1°, December 5°/−6°.
What is the weather like in Lanzhou in summer?
In summer, June through August, Lanzhou is warm. Afternoons run 28–29°C and nights 16–19°C; July is the warmest month. Rain picks up through the season: 7 rainy days and 64 mm in June, 11 days and 107 mm in August. No season is wetter.
What is the weather like in Lanzhou in winter?
December to February is winter in Lanzhou, and it is dry and cold. Expect 3–7°C by day and −8 to −5°C at night, with January the coldest month. Hardly any rain or snow falls.
What is the weather like in Lanzhou in spring?
In spring, March through May, Lanzhou is mild. March starts at 14°C by day and 1°C at night; by May it is 24°C and 12°C. Rain picks up through the season: 3 rainy days and 18 mm in March, 6 days and 46 mm in May.
What is the weather like in Lanzhou in autumn?
In autumn, September through November, Lanzhou is fairly mild. September still brings 23°C afternoons and 13°C nights, November only 10°C and −1°C. Rain eases through the season: 10 rainy days and 81 mm in September, 2 days and 12 mm in November.
How many days a year does it rain in Lanzhou?
On long-term average, Lanzhou has about 63 days a year with at least 2 mm of rain or snow. The annual total is roughly 526 mm.

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