Indonesia Climate – July 2026 Update
Top 5 Cities: Jakarta, Surabaya, Bandung, Medan, and Semarang
Summary
Indonesia experienced its 3rd warmest July on record as an unusually fierce dry spell triggered widespread forest fires across Java, Sumatra and Kalimantan, sending transboundary haze across Southeast Asia. Temperatures averaged 25.44°C, sitting 1.4°C above the 1961–1990 baseline and compounding severe drought conditions that have scorched thousands of hectares of peatland and national parks. The intensifying heat and dryness coincide with a moderate El Niño forecast to peak at Very Strong in Sep-Nov, with severe fire risks and water shortages expected to persist into early autumn.
This month in numbers
July 2026 brought exceptional heat across the archipelago, recording an average temperature of 25.44°C. This represents an anomaly of +1.4°C above the 1961–1990 baseline, making it the 3rd warmest July in 87 years of records, behind only the record set in 2024. The latest 3-month period from May to July 2026 was similarly severe, averaging 25.63°C with a +1.2°C anomaly to mark the 4th warmest such season on record. Globally, land temperatures in July also ranked as the 3rd warmest ever recorded, reflecting widespread thermal stress.
What changed
The warmth of May to July continues a relentless long-term trajectory for Indonesia, where temperatures have risen by +1.23°C overall against the 1961–1990 reference period. This 3-month stretch ran 1.2°C above average across the nation, following 2025 ranking as the 6th warmest complete year on record with an average of 25.51°C. While Indonesia ran slightly cooler than the global land average anomaly of +1.5°C over the same 3-month window, the cumulative impact of consecutive warm seasons has left regional soils severely depleted of moisture.
What’s driving change?
The primary catalyst behind the heatwave and expanding dry spell is ENSO, with a moderate El Niño currently active in the tropical Pacific and tracked at ENSO. Historically, El Niño brings warmer and drier conditions to Maritime Southeast Asia with roughly 80% reliability, suppressing regional rainfall through severe . Widespread and land clearing have further weakened the ability of local ecosystems to retain moisture. All of Indonesia's 1 wildfire tracked on our global system this year occurred in the past month, with live monitoring available at Extreme Weather tracker.
Looking ahead
Seasonal forecasts indicate that El Niño has a 93% probability of reaching Very Strong strength between September and November, threatening to prolong drought conditions, agricultural stress and heightened fire risks across Indonesia well into late 2026.
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 – Indonesia
Köppen Af · TropicalIndonesia has a tropical climate (Köppen Af: Tropical rainforest), with little variation in temperature or rainfall across the year. May is typically the warmest month, averaging 26.0°C, while July is the coldest at 25.3°C. Annual precipitation averages around 3083mm, spread fairly evenly across the year.
Monthly climate normals (2016–2025) - bar colour and height show average temperature, the shaded area shows average monthly precipitation.
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Long-Term Trends
Combined Timeline – Indonesia
Precipitation, Sunshine, Frost and Snow are converted to standard deviations from their own average so they can share an axis with Temperature.
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Heatwave Days – Indonesia
Warm Spell Duration Index (WSDI) - 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 – Indonesia
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Monthly Temperature – Indonesia
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 – Indonesia
Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP) - Anomalies vs 1901-2000 mean
Shifting Seasons
Weakly seasonalKöppen Af · TropicalIndonesia is weakly seasonal - temperature barely changes across the year (0.6°C range) and rainfall is fairly even. The clearest climate signal here is overall warming: monthly temperature has risen in every month.
Baseline vs recent monthly temperature climatology. Biggest warming: Jan (+1.7°C).
Data: Our World in Data / NOAA (precipitation: GPCC (DWD); frost: World Bank CCKP).
Climate Systems
Loading ENSO tracker…
Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for Indonesia
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 Indonesia changing?
Indonesia 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 Indonesia?
Indonesia has a tropical climate (Köppen Af: Tropical rainforest), with little variation in temperature or rainfall across the year. May is typically the warmest month, averaging 26.0°C, while July is the coldest at 25.3°C. Annual precipitation averages around 3083mm, spread fairly evenly across the year.
Where does the climate data for Indonesia come from?
Climate data for Indonesia 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 Indonesia climate data cover?
The Indonesia climate profile covers Jakarta, Surabaya, Bandung, Medan and surrounding areas. Temperature, rainfall and emissions data for Indonesia
How often is the Indonesia climate update refreshed?
The Indonesia 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 Indonesia 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 Indonesia 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.