Bali Weather in September: What the Month Really Does

September is the last full month of the Bali dry season, and it behaves like it. Around 30 °C by day, three or four days with rain on them across the whole month, nine hours of sun, and the calmest sea of the year for the crossings to the Nusa islands.

Every guide tells you that much. None of them tell you that the month splits into three, that the middle ten days are the best window on the Bali calendar, or that the last week fills the south coast back up with Australian school holidays. September also has one real weakness, and it is the thing half the island is photographed for.

On this page

September in figures

Orders of magnitude measured on the south coast, which is where every published average for Bali comes from. Ubud runs wetter and cooler at night, and above a thousand metres none of it applies.

Day	30 °C	86 °F, and 29 to 31 through the month
Night	23 °C	73 °F, the coolest nights of the year
Sea	27 to 28 °C	81 to 82 °F, no wetsuit needed
Rain	45 to 50 mm	three or four days with rain on them
Sun	9 h	average per day, the year's high with August
Humidity	About 78 %	against 85 in January

Is September a good time to visit Bali

One of the three best months

Yes, and for most kinds of trip it is a top three pick. Nothing gets cancelled, nothing floods, the roads are dry and every part of the island is open. The dry air has also lifted the haze that hides the volcanoes for half the year, which is what decides whether the Gates of Heaven at Lempuyang has a mountain behind it or a white sky.

Two caveats, and both are about timing rather than weather. The smaller waterfalls are at their lowest flow of the year, and the last week of the month lands on Australian school holidays.

Is September right for your trip

A month does not have one quality. It has as many as there are reasons to come, and September is the clearest case of it on the calendar: the best month of the year for anything underwater, and the weakest for the falls.

Diving in September: The best month of the year

The best month for this. Nothing else on the calendar comes close. Six months without runoff have left the water around the Nusa islands as clear as it gets, commonly 25 to 30 metres at Crystal Bay against half that in February. The mola mola season runs roughly July to October, and the manta cleaning stations work all year round. Respect the current at Crystal Bay: it runs strong and cold whatever the surface looks like.

Manta Point and what you actually see there

Surfing in September: Excellent, and thinning out

The best month for this. The south west swell is still arriving and the trade winds still blow offshore on the Bukit in the morning, so Uluwatu and Padang Padang work the way they do in August. What changes is the line up. From the second week the crowd drops sharply and stays down until the Australian break. The swell eases late in the month, which suits anyone who found August too big.

Families in September: Strong, if you pick the window

Strong month for this. Warm sea, almost no rain, and the coolest nights of the year to sleep through. The catch is timing: Australian school holidays land you in the busiest and most expensive ten days of the month, on the stretch of coast where every other family goes. Base yourself away from Seminyak and Kuta, or book four to five months out rather than two.

What a Nusa Penida day trip really involves

Couples in September: The middle ten days, easily

Strong month for this. Sunsets are reliable, evenings are dry enough to eat outside every night, and the nights are the coolest of the year, which matters more than people expect in a room without air conditioning. The clifftop places on the Bukit and the valley hotels around Ubud both drop their rates in the second week.

Budget in September: Fine, and better in October

Fine month for this. September costs less than August and more than anything from November to March. You are buying the weather, and the weather is worth something. But if price decides your trip, October and April deliver almost the same conditions for twenty to thirty percent less, and February costs under half.

Waterfalls in September: The weakest month for this

Poor month for this. Six months into the dry season the smaller falls are at their lowest flow of the year. Tibumana and Kanto Lampo run thin. The big north coast falls still carry enough water, and the light beam at Tukad Cepung is actually better now, because the gorge is not full of spray. If falls are the reason for the trip, come in April.

Which Bali waterfalls hold up in the dry season

First time in September: One of the two safest picks

Strong month for this. For a first trip you want the weather to be a non issue, and in September it is. That leaves you free to make the mistakes that actually cost people days here: underestimating the traffic between the south and Ubud, and arriving at famous sites at eleven in the morning.

The Gates of Heaven, and the queue nobody warns you about

September is not one month

The weather barely changes across the thirty days. Everything else does. Two school calendars on opposite sides of the world land at either end of the month and leave a gap in the middle, and moving a trip by eight days is the cheapest upgrade on this page.

1 to 10 September: The tail of the high season

Northern summer trips are still landing and rooms booked in June are still occupied. Famous sites look exactly like August: full from mid morning, quiet again after four. Rates have started to slip but the drop has not reached the good places. You are paying August money for slightly better weather.

11 to 20 September: The quiet window

The best ten days on the Bali calendar, and almost nothing published about the month mentions them. Northern summer has ended, the Australian break has not started, and the dry season is still at full strength. Sites that queue in August are walkable, and rooms drop noticeably. If you have any freedom over your dates, put them here.

21 to 30 September: The Australian school break

The end of Term 3 sends a concentrated wave of Australian families to the south coast: Seminyak, Legian, Kuta, Nusa Dua. Flights out of Perth, Melbourne and Sydney get expensive and family rooms go early. Ubud and the east barely notice it. The dates move by state, so check yours before you book.

What September does badly

Thin sheets of water spread across the stepped rock wall of Kanto Lampo waterfall near Gianyar, Bali — Wide, thin and photogenic in its own way. It is not the wall of white water that the picture on the booking page shows.

Six months into the dry season, the rivers that feed the smaller falls run at their lowest of the year. Pools are shallow and warm, and the photograph you saved was almost certainly taken in February or March, when the same fall is three times the volume and the colour of milky tea.

That trade is not all one way. Low water means the pools are clear enough to swim in, which they are not in the wet season, and the paths down are dry rather than slick clay.

If falls are the reason for the trip, the honest answer is April. If they are one stop among ten, pick the ones with a catchment behind them and use the waterfall guide to skip the two that will disappoint you this month.

Booking around September

In the wet season you book a tour for the free cancellation. In September you book because the good boats and the good drivers run out, and they run out first in the last week. The weather will not let you down. Availability will.

A small tour boat running along the limestone cliffs of Nusa Penida on a calm sea

From≈ $28/ pers.

September, the reliable month

Free cancellation

Bali day tours and island boat trips

Duration: 3 to 12 hFrom ≈ $28 / pers.

✓Crossings to the Nusa islands run on schedule from June to October
✓The clearest water of the year for snorkelling and diving trips
✓Free cancellation on most listings, which covers a change of dates
✓Sunrise departures work: the haze has lifted and Agung is visible

See Bali tours and activities

Affiliate link. Booking through GetYourGuide costs you nothing extra and supports the guide. Prices are indicative and vary by option and season.

Bali in September: common questions

Temperature, rain, the sea, crowds and what to wear.

Is September a good time to go to Bali?

Yes, and for most kinds of trip it is one of the three best months. It closes the dry season, so you get around nine hours of sun a day, three or four days with rain on them across the whole month, and the calmest sea of the year for the island crossings. Two caveats are worth knowing before you book. The smaller waterfalls are at their lowest flow of the year, and the last week coincides with Australian school holidays, which fills the south coast again.

How hot is Bali in September?

Daytime highs on the coast sit around 30 °C, or 86 °F, with the range across the month running from about 29 to 31 °C. Nights drop to roughly 23 °C, 73 °F, the coolest nights of the Bali year. Ubud runs two or three degrees cooler after dark, and the highlands around Kintamani are genuinely cold at dawn, closer to 15 °C.

Does it rain much in Bali in September?

Very little. Expect somewhere around 45 to 50 mm across the whole month, spread over three or four days, and that rain usually falls as a short afternoon shower rather than a wet day. Rain becomes a real planning variable again in the second half of October.

What is the humidity in Bali in September?

Around 78 percent, against roughly 85 percent in January. That sounds like a small difference and it is the difference between a day of walking that works and one that does not. Temperature on Bali barely moves across the year, so humidity is what makes one month feel heavier than another.

How should I dress in Bali in September?

Light, breathable clothes for the day, plus three specific additions. Covered shoulders and knees for temple visits, or a sarong hired at the gate. One warm layer for the highlands and for any sunrise trek, which is the thing people most often wish they had packed. And shoes with grip for waterfall paths, which stay slick even in the dry season. A rain jacket is not worth the space this month.

Which is better in Bali, September or October?

September for reliability, October for value. September gives you clearer water, more certain skies and the better sea for the islands. October gives you noticeably lower prices, quieter sites all month rather than for ten days, and a landscape that greens up once the first rains arrive. If your trip depends on diving or on reaching Nusa Penida, take September. If it depends on the budget, take October.

Are boats to Nusa Penida cancelled in September?

Almost never. The crossing from Sanur is at its most reliable between June and October. Cancellations on this route are a wet season problem, concentrated between December and March. In September the thing that stops you reaching Penida is a fully booked boat during the Australian school break, not the sea.

Bali weather in September