Weather in Bali in September

How September compares

September is the 10th warmest month of the year in Bali and ranks 67th of 134 destinations we compare for September - see where else is hot in September. Against London's average high of 18.6°C in September, Bali is 8.2°C warmer by day and 12.0°C warmer at night.

Daytime and night-time in September

The typical September day in Bali peaks at 26.8°C, but that is an average: the warmest 10% of days reach 27.8°C or more. About 99% of days top 25°C and 1 in 1000 pass 30°C. Nights average 23.2°C; one night in ten drops to 22.0°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 30.1°C (2018-09-30) and the coldest night 19.8°C (2007-09-11).

Rain in September

Wet (more than 8 rainy days): about 13 days with 1 mm or more, 43 mm in total. Year to year it varies a lot - the wettest September was 2010 with 196 mm, the driest 2014 with 6 mm. Humidity averages 83%.

Sea temperature in September

The sea averages 26.0°C - warm enough to swim (22°c+). Depending on the year it ranges from 25.3°C to 27.0°C. For the warmest sea here, come in February (28.9°C).

Sunshine and daylight

Around 5.6 hours of sunshine a day (estimated from cloud cover), 12.0 hours of daylight: the sun rises about 06:13 and sets about 18:16 local time in mid-September. Average cloud cover is 53%.

Is September a good time to visit Bali?

It is a reasonable choice: hot days but expect showers. The best months for Bali on our scoring are August, September, July; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Warm rather than fiercely hot, but noticeably humid

September sits towards the cooler end of Bali's year, although it will still feel hot coming from the UK. Almost every day reaches 25°C, so summer clothing should be your default rather than something you save for a lucky sunny spell. Humidity averages 83%, which can make walking around feel more tiring than the temperature alone suggests. Choose loose, breathable clothes and allow for breaks around midday rather than packing your schedule tightly. Evenings offer only modest relief from the daytime warmth, so this is not a month for travellers who need cool nights to feel comfortable. Prioritise accommodation where you can sleep comfortably in warm conditions.

Expect interruptions from rain, not guaranteed sunshine

Rain is a real part of the September picture, with about 12 rainy days during the month. That is enough to make a completely fixed outdoor itinerary a poor fit, but it need not put you off if you can adjust your plans. Carry a light waterproof and keep an indoor alternative available when the weather turns. Sunshine averages about 5.6 hours within 12 hours of daylight, so there is a useful amount of sun without a promise of blue skies all day. September suits travellers happy to take sunny opportunities as they come; it is less suitable if uninterrupted sun is the main reason for making the journey.

Comfortable sea temperatures help justify the journey

The sea is a strong reason to choose September: at an average 26°C, it is warm enough for swimming without the bracing entry you might expect at home. The year-to-year range of 25°C to 27°C also keeps it comfortably in swimming territory. Water temperature alone does not tell you about swimming conditions, so follow local safety advice. For a UK traveller, the bigger practical trade-off is the journey, with a flight from London taking about 16 h 24 min. Bali makes more sense if warm water and consistently warm air matter more to you than avoiding a long-haul flight or securing an entirely dry holiday.