🇮🇩 Climate · air · address · alerts
Weather, air quality and natural hazards in Bali
Bali's wet and dry seasons are a useful starting point, but conditions still vary around the island. BMKG divides Indonesia into local Seasonal Zones because the timing and character of rainfall differ. The coast, elevation and side of the island all affect heat, rain, wind, flooding, slopes and evacuation planning.
Last verified 1 September 2026
The short answer
What weather and natural hazards should families plan for in Bali?
Bali is commonly wetter around October or November through April and drier around May to September, but the exact onset and intensity must come from BMKG’s current Bali and Seasonal Zone outlooks. Sanur needs coastal, flood and tsunami-route evidence; Canggu needs drainage, river, road and coastal checks; Ubud trades direct coastal tsunami exposure for slope, ravine and access risks. Every address also needs earthquake and volcanic-disruption planning.
Five kinds of weather information
Use the right source for the question you are asking
A climate average, seasonal outlook and live warning answer different questions. The time period becomes shorter from left to right, so the decisions you can make also change.
- 1
Decades
Climate normal
Use it toCompare the broad character of places: typical heat, rainfall and seasonality.
Not toChoosing a moving day or proving a home will not flood.
- 2
Weeks to months
Seasonal outlook
Use it toSee whether a season may lean wetter, drier, hotter or cooler than usual.
Not toA street-level forecast or promise of uninterrupted weather.
- 3
Hours to days
Forecast
Use it toPlan journeys, school days, outdoor activity and household preparation.
Not toA guarantee; uncertainty grows with time and local terrain.
- 4
Now
Nowcast + observation
Use it toRead radar, gauges, air monitors, river levels and conditions already developing.
Not toReplacing instructions issued by an authority.
- 5
Action window
Official warning
Use it toFollow the named hazard, area, severity and protective instructions.
Not toA reason to wait for social-media confirmation.
A useful seasonal overview
Understand the usual seasons, then check the local outlook
These periods describe broad planning patterns, not guaranteed start dates or daily forecasts. Coast, elevation, local climate zone and the individual year can change the result.
Broad wetter rhythm
Higher rain and humidity are common, with intense storms, flooding and slope impacts possible; onset varies by local zone and year.
Check mould, drains, roof, access roads, backup power and a realistic school/hospital route.
Broad drier rhythm
Often lower rainfall and less humidity, but showers, strong coastal conditions, drought and fire-related effects remain possible.
Do not treat dry season as hazard-free; recheck waves, wind, water and air.
Onset is not a switch
Thunderstorms and rainfall can change rapidly while different Bali zones enter or leave the season at different times.
Use BMKG Bali 10-day/monthly products rather than a travel-blog calendar.
Geological hazards
Earthquakes, tsunamis and volcanic activity do not belong to a rainy-season timetable.
Know the address layer, natural warnings and route before an event.
How to compare air quality
Start with the official monitor, not an unexplained AQI number
Indices can use different pollutants, averaging periods, breakpoints and category names. Check what the official local reading measures before comparing it with another source.
Official source
Use BMKG PM2.5 observations and forecasts; the Bali Climate Station also publishes local PM2.5 products.
Local pattern
Traffic, weather, local/regional smoke and volcanic ash can affect air differently. Ash is a geological emergency issue and should follow official volcano/disaster advice.
Research it
Check the nearest useful monitor and local prevailing conditions; ask buildings and schools about filtration, ventilation, ash clean-up and power.
Plan the family response
Use official health and disaster advice, keep masks/medicines appropriate to professional advice, and know when to shelter, change activity or move under authority instruction.
Check the exact address
Five details to investigate for every promising home
A map pin is only a starting point. It cannot tell you whether the building leaks, the basement floods, the school journey becomes unusable or the generator powers the lift.
Map the exact pin
Check flood, landslide, storm-surge, tsunami, earthquake or volcano layers that apply. Save the result and its date; a city-wide label is too broad.
Read the building
Ask for prior water ingress, drainage, finished-floor level, slope or retaining-wall history, roof and window repairs, generator coverage and water storage.
Check essential journeys
Map two routes to school, work and hospital. Look for rivers, underpasses, bridges, steep roads, ferries and coastal sections that severe weather could affect at the same time.
Test utilities + air
Confirm backup power, pumps, mobile signal, safe water, ventilation, filtration and a room the family can use during heat, smoke or ash.
Know who will contact you
Ask the school, landlord, insurer and employer who decides on closures, evacuation, sheltering, remote work, repairs and temporary accommodation—and how they will notify you.
Ask what each hazard means for the home
Turn natural hazards into practical property questions
Living in an exposed area does not mean damage is inevitable. Check what applies to the exact address, how the building and essential journeys cope and where current instructions come from.
| Hazard | How it may affect the area | What to check at the address | Live source |
|---|---|---|---|
| Flood + flash flood | Intense wet-season rain, constrained drainage, rivers and low roads can affect southern/western growth areas. | InaRISK layer, prior water, drains, floor/road level, ravine/river distance and two routes. | BMKG Bali + BPBD |
| Landslide | Steep terrain, cut slopes, ravines and saturated ground affect inland and upland addresses. | InaRISK, retaining/drainage evidence, cracks, previous movement and alternate access. | BMKG rain warnings + BPBD |
| Earthquake + tsunami | Bali is in a seismically active region; coastal tsunami exposure depends on the exact location and elevation. | InaRISK, building evidence, natural-warning knowledge and signed inland/vertical evacuation route. | BMKG + BPBD Bali |
| Volcano + ash | Eruptions can affect air, roads, water, schools and flights beyond the immediate exclusion zone. | Official hazard zone, ash plan, water/air protection, transport and insurer wording. | MAGMA Indonesia/PVMBG + BPBD |
| Extreme waves, drought + fire | Coasts and water-based transport face wave/wind hazards; dry periods can strain water and increase fire risk. | BMKG marine outlook, water storage/source, fire access and no single ferry route. | BMKG Bali + BPBD |
Conditions vary within each city
Compare the main weather issue in each likely family base
Use these summaries to guide further research. They are not neighbourhood ratings, and individual properties can face very different conditions.
Sanur
- Usual pattern
- Low-lying east/southeast coast with seasonal rain and marine exposure.
- Look out for
- Flood/drainage, quake, tsunami and coastal route interruption.
- Check locally
- InaRISK pin, elevation, signed inland/vertical route, road level and building history.
Canggu / west-south
- Usual pattern
- Warm coastal growth area where wet-season rain meets rivers, drainage and congested roads.
- Look out for
- Local flood, river overflow, coastal waves/tsunami, quake and route failure.
- Check locally
- Water history, drain/river position, two car routes and current hazard layers.
Ubud
- Usual pattern
- Higher/inland, often wetter/cooler than the southern coast with ravines and steep local terrain.
- Look out for
- Landslide, flash flood, quake, road access and volcanic ash/disruption; central Ubud is not a coastal tsunami base.
- Check locally
- Slope/ravine layer, retaining/drainage, road redundancy and ash/utility plan.
Set up weather alerts before you need them
Save official sources before severe weather arrives
Use national services for official observations and warnings, then local channels for instructions about the building, school, roads and evacuation.
Local climate
BMKG Bali rainfall, 10-day, monthly, seasonal, PM2.5, wind and wave products.
LimitIsland-wide wet/dry dates cannot replace the local Seasonal Zone outlook.
National warning
BMKG warnings for weather, earthquake and tsunami.
LimitFor a strong/long earthquake near the coast, know natural warnings and local evacuation guidance.
Address risk
InaRISK multi-hazard layers and Bali dashboard.
LimitScenario/scale limits mean the map must be paired with site evidence.
Local disaster
BPBD Bali messages and preparedness information.
LimitVolcano information should come from PVMBG/MAGMA and the authorised local response.
Five assumptions to avoid
Do not let a short viewing hide weather-related problems
Each assumption can seem reasonable during a viewing or scouting trip but prove wrong when the conditions change.
October to April as a guarantee
BMKG Seasonal Zone onset and rainfall character vary by year and location.
An inland base as hazard-free
Ubud reduces direct coastal exposure but adds slope, ravine, road and ash considerations.
A tsunami app without a route
Know natural warnings and the signed inland or vertical route from home, school and beach.
Ash judged by visibility
Follow official volcano, air and disaster advice; protect water and indoor air as instructed.
A scooter as emergency transport
Plan weather-resilient car access and a backup route to school and hospital.
Connect the family plan
Use weather research throughout the rest of the move
Apply what you learn to housing, transport, healthcare, insurance and emergency planning.
Common questions
Questions about weather and natural hazards in Bali
Does monsoon mean it rains all day?
No. A monsoon is a seasonal wind regime, not a promise of continuous rain. It can bring short intense storms, longer wet spells, rough seas and flooding, while individual days may still be dry. Timing and impact differ by coast, elevation and year, so use the official local outlook and forecast rather than a country-wide label.
Can I compare air-quality index numbers between countries?
Not safely from the number alone. National indices can use different pollutants, averaging periods, breakpoints and categories. Read the official index definition, pollutant and station time, then follow health advice from the local authority and a clinician for asthma, pregnancy or other vulnerabilities.
How can I check whether a rental is likely to flood?
Start with the official hazard map, then ask for building-specific evidence: previous ingress and repairs, floor level, drains, pumps, basement parking, access roads, utility shut-offs and insurance. Revisit in heavy rain if possible. A map is a screening layer, not a property survey or guarantee.
Should we buy an air purifier before moving?
First identify the room size, likely pollutant, official monitoring source and family health needs. If filtration is appropriate, compare clean-air delivery for the room, filter availability and cost, noise, seals and backup power. A purifier does not make all outdoor exposure safe; discuss medical action plans with a clinician.
Are historic monthly averages enough to choose a moving date?
No. Averages help compare broad patterns but hide extremes and do not predict a particular week. Recheck the seasonal outlook, short-range forecast, current observations and official warnings close to travel, and keep flexible transport and accommodation arrangements.
What should a family do when an official warning is issued?
Use the issuing agency’s wording for the named place and hazard, then follow local authority, school, building and emergency-service instructions. Keep phones charged, preserve offline contacts and documents, and avoid self-directed travel through floodwater, ash, severe wind or closed routes.
When is the rainy season in Bali?
Bali is commonly wetter from around October or November to April and drier around May to September, but these are broad planning labels. BMKG uses local Seasonal Zones because onset, peak and rainfall character vary. Check the current BMKG Bali and national seasonal products for the exact area and year.
How can I check tsunami risk for a Bali home?
Screen the exact pin in InaRISK and use BPBD/BMKG local evacuation information. Then walk the signed route from home, school and frequently used coast, noting bridges, rivers, gates, night access and vertical options. A map or alert app is not a substitute for recognising natural warnings and moving as officially instructed.