Short answer
Bali's 2026/27 rainy season is forecast to start in late November in 3 zones and in December in the other 17. Have your roof, drain and rental checks done by late November.[2]
- Usual season in Indonesia
- October to March
- 2026/27 start
- Late November to December
- 2026/27 peak
- February 2027
- Denpasar rain, January
- 388 mm
In detail
When is the rainy season in Bali?
The rainy season usually runs from October to March, six months. In Eastern Indonesia the wet season can run April to August instead.[1]
This year's start does not match the generic window. BMKG (Indonesia's weather and earthquake agency) counts a region as rainy once a dasarian (ten-day period) brings 50 mm or more, with more to follow.[4]
How bad is the rainy season in Bali?
Denpasar averages 388.4 mm over 18.8 rain days in January, against 16.1 mm over 1.9 rain days in August.[5]
| Period | Rain (mm) | Rain days |
|---|---|---|
| January | 388.4 | 18.8 |
| August | 16.1 | 1.9 |
| Whole year | 1,742.2 | 107.6 |
January brings about 22% of the year's rain at Denpasar (our estimate, 388.4 against 1,742.2 mm) and about 24 times August's (our estimate, 388.4 against 16.1 mm).
Flooding follows the rain. Bali can suffer severe localised flooding, with major traffic jams and power outages.[1]
When is the peak of the rainy season?
The peak is forecast for February 2027.[3]
The start splits the island in two: three zones, about 15% of Bali, start in late November 2026, and the other 17, 85%, start in December 2026.[2]
| Season zones | Share of Bali | Rainy season starts |
|---|---|---|
| 3 | 15% | Late November 2026 |
| 17 | 85% | December 2026 |
December is about two months after the usual October start (our estimate, 1 October to 1 December is 61 days). The outlook also expects El Niño, which brings a longer dry season in Indonesia.[2]
Our rule
Be ready by late November, and be most careful in February 2027.
Those are the first start and the forecast peak.
What disruptions should residents expect in the rainy season?
Three things recur: floods and power cuts, trees and landslides, and dengue.
On floods, Sanur, Kuta, Seminyak, Padangsambian and Renon are the areas that generally flood.[8]
One extreme-weather day logged 76 incidents across Bali, 42 of them floods; Denpasar had 36 incidents and Badung 12, and more than 30 people were evacuated.[6]
Trees and slopes fail too. January 2026 brought 495 disasters, up 278 (about 128%) on January 2025: 214 fallen trees, 106 landslides, 85 extreme-weather events and 11 floods.[7]
On the road, put off long journeys in heavy rain when you can, especially where the route crosses flood-prone ground.[15]
Slow down before standing water rather than swerving around it: a rider swerving round a puddle can cross into oncoming traffic, brakes work less well on a wet road, and a puddle can hide a hole.[16, 17]
Dengue follows the rain. Through July 2026, cases stayed under 300 a month in Bali.[10]
January to July 2026 brought 1,588 cases, about 227 a month (our estimate, 1,588 over seven months).[11]
Cases usually begin to rise at the end of November, and rainfall is one of the reasons.[12]
What should I do before and during the rainy season?
Start with the home.
Clear the drain outside your gate
Clear your own channel and lift litter before the rains. Floods can ease where each household keeps its channel clean, and soakage holes (biopori) help too.[18]
Cover and empty water containers
Drain water containers, close them tightly and recycle used items that can hold water. See a doctor for a sudden fever lasting more than two days.[12]
Save the numbers
Keep the Bali disaster agency (BPBD) on 0361 245397 and the BMKG Bali forecast at mhews.bmkg.go.id/bali-forecast.[13]
Emergency lines are ambulance 118, fire 112 and police 110.[14]
In heavy rain, stay clear of trees and rivers
Keeping away from large trees and watching for rivers rising can matter in heavy rain.[8]
Authorities are preparing as well: a flood siren now stands on Tukad Badung, and Denpasar has run a contingency-plan simulation after the heavy rain and flooding of 2025.[9]
When does the rainy season end?
The usual end is March.[1]
No end date is published for 2026/27, but the outlook gives the length: on average 10 to 15 dasarian, which is about 14 to 21 weeks (our estimate, 100 to 150 days), with 10 to 12 in some zones and 16 to 18 in others.[2]
It also predicts a shorter season.[3]
Next steps
FAQ
Sources
Our summaries of Indonesian rules are unofficial; the Indonesian text governs.
UK Foreign, Commonwealth and Development Office, Indonesia travel advice: safety and security
Wikipedia, Musim hujan (rainy season)
Wikipedia, Denpasar: climate table
Antara Bali, BPBD: 495 disasters in Bali during January 2026
Antara Bali, BPBD: two incidents from a full day of rain in Bali
Antara Bali, Beware dengue fever: two toddlers die in Bali
Bali Provincial Disaster Management Agency (BPBD), BPBD Bali (home page)
UK Foreign, Commonwealth and Development Office, Indonesia travel advice: getting help
Bali Post, Avoiding a puddle, rider hit by truck
Antara Bali, 16 tips for riding safely in the rain
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