Japan Climate – July 2026 Update
Top 5 Cities: Tokyo, Osaka, Yokohama, Nagoya, and Sapporo
Summary
Japan has experienced exceptional summer warmth, recording its 4th warmest May-July period since records began in 1940. The persistent heat brought five consecutive days above 40°C during July, sending thousands to hospital with severe heatstroke across dozens of prefectures. This regional swelter aligns with tropical warmth driven by a moderate El Niño forecast to peak at Very Strong in Oct-Dec with an 81% probability. Although severe heatstroke alerts overwhelmed local emergency infrastructure, Japan avoided the large-scale flood disasters currently tracked in neighbouring China at Extreme Weather tracker. High temperatures are projected to continue through late summer.
This month in numbers
July 2026 registered an average temperature of 24.12°C, which sits 2.1°C above the 1961-1990 baseline and ranks as the 8th warmest single month in 87 years of record-keeping. The seasonal May-July average reached 19.81°C, standing 1.6°C above normal as the 4th warmest such period on record. Globally, July land temperatures ranked 3rd highest on record at 15.8°C (+1.6°C anomaly), while the global three-month land average of 14.34°C ranked 2nd warmest overall.
What changed
The latest three-month trend highlights sustained warming across East Asia. Within the 23 member countries of the Asia continental group on our regional tracker Asia, Japan ranked as the 5th warmest nation by single-month anomaly, running 0.51°C above the group average of +1.57°C. While European nations dominated the highest global anomalies this month, Japan continues its longer-term warming trajectory (+1.63°C overall trend), following its 3rd warmest year on record in 2025.
What’s driving change?
Multiple atmospheric mechanisms generated the dangerous summer conditions. The Japan Meteorological Agency identified pushing the westerly jet northwards, allowing atmospheric beneath the Pacific High and Tibetan High pressure systems to lock stifling air over Honshu. Because , these inland high-pressure bubbles intensified rapidly. Meanwhile, a moderate El Niño active in the tropical Pacific, tracked at ENSO, continues to nudge global temperatures upward, though historical records show its direct winter teleconnections to East Asia carry moderate uncertainty.
Looking ahead
Seasonal models indicate that above-normal temperatures will likely persist across western Japan through late summer and into autumn, with the ongoing tropical Pacific warming expected to peak late in the year.
Sources:
Generated by Gemini from climate data and web sources
At a Glance
Temperature – Average
Climate Map – Global
Source: NOAA Climate at a Glance (countries & continents) · Met Office (UK) · US states & climate regions. Anomalies are vs the 1961–1990 baseline. See methodology.
Typical Climate – Japan
Köppen Cfa · TemperateJapan has a temperate climate (Köppen Cfa: Humid subtropical), with distinct warm summers and cool-to-cold winters. August is typically the warmest month, averaging 24.9°C, while January is the coldest at 1.1°C. Annual precipitation averages around 1688mm, spread fairly evenly across the year.
Monthly climate normals (2016–2025) - bar colour and height show average temperature, the shaded area shows average monthly rain, with snow (water-equivalent) shown separately.
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Long-Term Trends
Combined Timeline – Japan
Right axis: everything else standardized to standard deviations (σ) from its own average, since mm/hours/days aren't directly comparable to °C or to each other.
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Heatwave Days – Japan
Warm Spell Duration Index (WSDI) - the WMO/ETCCDI heatwave measure: days in a 6+ day run above the local 90th-percentile temperature for that time of year.
Data: World Bank Climate Change Knowledge Portal (ERA5-derived). Refreshed roughly 1-2x/year, ~7-8 months behind present.
Year-on-Year Trends
The 4byo Climate Helix – Japan
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Monthly Temperature – Japan
Background lines show the last 40 years (plus the record year and its opposite, wherever they fall).
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Records – Japan
Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP) - Anomalies vs 1901-2000 mean
Shifting Seasons
Warm / cold seasonsKöppen Dfa · ContinentalHow spring and autumn have shifted in Japan. Spring is defined as the date monthly temperatures first rise above the long-term annual mean (10.7°C, from 1940–1969); autumn is the date they fall back below it. Temperature swings 24.2°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Mar (+2.9°C).
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for Japan
Every figure on this page is sourced from official, openly published climate datasets. Anomalies are calculated against the 1961–1990 baseline (temperature) and 1991–2020 (rainfall, sunshine, frost) - see the Methodology & Sources page for the complete dataset list and update calendar.
Country-level temperature anomaly, sourced from Copernicus ERA5 and Hadley HadCRUT5.
Annual country and global CO₂ emissions, from the Global Carbon Project.
Monthly rainfall - Global Precipitation Climatology Centre (DWD) preferred, World Bank CCKP/CRU TS fallback where GPCC lacks direct coverage.
Frost Days and Heatwave Days (Warm Spell Duration Index), ERA5-derived. World Bank Climate Change Knowledge Portal.
Monthly snow water-equivalent, Global Precipitation Climatology Centre (DWD).
FAQs
FAQs
How is the climate in Japan changing?
Japan is warming in line with the rest of the world. The page above shows the latest monthly temperature anomaly versus the 1961-1990 baseline, the long-term annual trend, and the region's rank in the historical record. The headline panel also shows the long-term trend rate per decade and the warmest and coolest years on file.
What is the climate like in Japan?
Japan has a temperate climate (Köppen Cfa: Humid subtropical), with distinct warm summers and cool-to-cold winters. August is typically the warmest month, averaging 24.9°C, while January is the coldest at 1.1°C. Annual precipitation averages around 1688mm, spread fairly evenly across the year.
Where does the climate data for Japan come from?
Climate data for Japan comes from Our World in Data, sourcing Copernicus ERA5 and HadCRUT5 (national temperature anomaly) and the Global Carbon Project via Our World in Data (CO₂ emissions), refreshed every month, when the upstream temperature and rainfall data are refreshed.
What is the climate baseline used on this page?
Anomalies on this page are calculated against the 1961-1990 climatological baseline, which is the standard reference period used by the Met Office, NOAA, IPCC and most national climate services. Some panels also show the source-native 1901-2000 (NOAA) or 1991-2020 (WMO) baselines for verification. See Methodology & Sources for the full reference.
Which areas does the Japan climate data cover?
The Japan climate profile covers Tokyo, Osaka, Yokohama, Nagoya and surrounding areas. Temperature, rainfall and emissions data for Japan
How often is the Japan climate update refreshed?
The Japan climate update is refreshed monthly, typically a few days after the previous month closes and the upstream provider (Met Office HadUK-Grid, NOAA Climate at a Glance, Copernicus ERA5 or the Global Carbon Project) publishes its update. See the Climate Rankings for cross-region comparisons.
What counts as a Heatwave Day on the Japan climate page?
Heatwave Days use the Warm Spell Duration Index (WSDI) - the WMO/ETCCDI-standard heatwave measure: days that are part of a run of 6 or more consecutive days above the local 90th-percentile temperature for that calendar day. The 90th-percentile threshold varies by time of year (a hot day in January is judged differently to one in July) but is fixed to the 1961-1990 baseline for every year shown - it does not shift as the climate warms, which is why Heatwave Days trend upward over time.
Does the Japan climate page include frost and snow data?
Yes. Frost Days (days with a minimum temperature below 0°C, World Bank CCKP) and snow water-equivalent (GPCC) are shown alongside temperature and precipitation, each measured against the 1961-1990 baseline where a like-for-like historical comparison is available.