In short. Per the BMKG forecast of 2 October 2026, the rainy season in Bali this year will start later than usual because of a very strong El Nino: in the mountains near Bedugul from 21 to 30 November, in the south (Denpasar, Kuta, Canggu, Bukit) and in Ubud from 11 to 20 December, in the north, east and Nusa Penida from 21 to 31 December. The peak is almost everywhere in February, in the west in March. October, November and early December in the south are formally still the dry season. BMKG's main risks of the season: floods at the peak, landslides in the mountains, a rise in dengue.
What the forecast is. Twice a year the Indonesian state weather service BMKG issues a season forecast: in spring for the dry season, in autumn for the rainy one. The forecast for 2026/2027 came out on 2 October 2026, with a PDF book attached that has a table for each climate zone of the country. Bali has twenty such zones. The main reason this year is named directly: the El Nino index for June to August 2026 is +2.20, which is the "very strong El Nino" phase, and BMKG expects it to last until the start of 2027. El Nino reduces rainfall in Indonesia, so in almost all zones of Bali the season will start later than normal and be shorter.
How BMKG counts the start of the season. The year is divided into ten-day periods (dasarian): the first of a month runs from the 1st to the 10th, the second from the 11th to the 20th, the third from the 21st to the end of the month. The rainy season starts with the ten-day period in which at least 50 millimetres fell, if the next two periods also give 50 millimetres each, or together with it add up to 150. Individual downpours in October and November happen before this date, but they do not yet count as the season.
When it starts by area. A retelling of the table of Bali zones from the BMKG book, pages 91 to 92:
- South: Denpasar with Sanur, south Badung with Kuta, Seminyak, Canggu and the Bukit, south Tabanan and Gianyar. Start from 11 to 20 December, more than a month later than normal. Peak in February. The season is about 14 ten-day periods, roughly four and a half months. The amount of rain is within normal.
- Ubud and the centre of the island: middle Gianyar, Badung and Tabanan. Start from 11 to 20 December, peak in February, season 12 to 13 ten-day periods.
- Mountains: north Tabanan and Badung with Bedugul, north Gianyar. The rains come here earliest, from 21 to 30 November. Peak in January or February, the longest season on the island, 16 ten-day periods.
- Kintamani and north Bangli: start in the first or second ten days of December, peak in February.
- North, Lovina and the Buleleng coast: start from 21 to 31 December, peak in February, season about 11 ten-day periods. BMKG expects more rain than normal here.
- East, Amed and east Karangasem: start from 21 to 31 December, peak in February, also more rain than normal.
- Southeast, Klungkung, Candidasa and south Karangasem: start from 21 to 31 December, peak in February or March.
- Nusa Penida: start from 21 to 31 December, peak in February, the shortest season, about 10 ten-day periods.
- West, Jembrana with Negara and Medewi: start in the second or third ten days of December, peak in March.
What makes the season dangerous. In its recommendations for the forecast, BMKG names three risks. Downpours at the peak of the season cause floods. Long rain on slopes and in the hills causes landslides, which concerns mountain roads, Bedugul, Kintamani and the rice terraces. Humidity and standing water after the rains help the Aedes aegypti mosquitoes that carry dengue: BMKG expects a rise in cases. What to do with a fever is covered in the guide to dengue.
What BMKG advises. Follow the weather warnings of BMKG and the local disaster agency BPBD, including river water levels. Keep a grab bag with documents at home. If water comes up to the house, raise the vehicle and valuables higher and switch off the electricity if water has come inside. At the first signs of ground movement, leave at once without waiting for an order, and do not go back to the landslide site until it is declared safe. Do not throw rubbish into ditches and canals: a blocked drain turns an ordinary downpour into a flood on the street.
Frequently asked questions.
When is the south of Bali still dry? Per the BMKG forecast, the rainy season in Denpasar, Kuta, Canggu and on the Bukit will start from 11 to 20 December. October, November and early December there formally remain the dry season, although individual downpours are possible.
Is the forecast accurate? BMKG gives a probabilistic forecast by zone, and the date may shift. Last season the service updated its forecast in December, and we will correct this article when an update comes out.
Where to check today's weather? In the official Info BMKG app and on the bmkg.go.id site: there is a forecast by area and warnings about heavy rain. Earthquakes and tsunami are there too, covered in a separate guide.
What this means for you. October and November on most of Bali will, per the forecast, still be dry this year. This is the time to finish things with your scooter, the roof and the drains at the villa, check the mosquito nets and stock up on repellent. From December keep a rain poncho in the scooter's boot, and do not go to the mountains after heavy rain. At the peak of the season, in February, plan trips around the island with extra time and check the BMKG warnings before a long journey.