SeasonMapLake Toba (Toba) weather in September
Indonesia
September in Lake Toba: hot, soaked, with clean air — a gamble, with 28 rainy days.
#9 of 12 months in Lake Toba · #1091 of 1383 destinations to visit in September · comfort 61/100 (tier C)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Lake Toba in September
Other months in Lake Toba
Lake Toba's forum notes February sits within the wet season, though 'wet season' doesn't mean rain all day — the typical pattern is an intense shower in the late afternoon or overnight, with clear mornings common. Regulars describe rainfall as highly variable year to year in February, and put daytime temperatures around 25-27°C with nights cooling to the low 20s°C.
Add your own note from Lake Toba's card on the map.
Lake Toba climate normals — September
| Daytime high | 26°C / 79°F | 🥵 hot |
|---|---|---|
| Nighttime low | 21°C / 70°F | |
| Feels like (high) | 30°C / 86°F | |
| Rainfall | 285 mm / 11.2 in | ⛈ soaked |
| Rainy days | 28 days | |
| Humidity | 84% | 💦 very humid |
| Dew point | 20°C / 68°F | |
| Sunshine | 8.2 h/day | |
| Daylight | 12.1 h | |
| Wind | 6 km/h / 4 mph | |
| Air quality (US AQI) | 32 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Lake Toba in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyFestival Danau Toba, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Lake Toba's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherLake Toba's weather doesn't swing hard through the year — comfort stays fairly steady in every month.
What's on in Lake Toba in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Festival
Festival Danau Toba
1 Jun – 30 Sep · usuallyMajor festivalCrowdedThe regional government's flagship week of Batak music, canoe racing and dance, usually held on Samosir in the dry half of the year. The dates move and have been postponed more than once. Source ↗
- Season
Dry season
1 Jun – 30 Sep · usuallyThe clearest air and the flattest water of the year, when the far wall of the caldera is visible from Tuk Tuk all day. Nights on the lake stay cool enough for a blanket.
- Hazard
Sumatran haze
15 Jul – 15 Oct · usuallySmoke seasonIn a dry year, smoke from land clearing further south on the island drifts north and the caldera rim goes flat and grey. Some years it never arrives at all. Source ↗
- Season
Wet season
MonsoonRisk28 rainy days and about 285 mm in the month — the real kind of rainy season, not afternoon showers.
from the climate normals
Where is Lake Toba?
Lake Toba in September — FAQ
- Is September a good time to visit Lake Toba?
- September in Lake Toba: hot, soaked, with clean air — a gamble, with 28 rainy days. It ranks #9 of 12 months for Lake Toba on SeasonMap's comfort score (61/100).
- What is the weather like in Lake Toba in September?
- In September, Lake Toba averages a daily high of 25.9°C and a low of 21.3°C, with about 285.2 mm of rain over roughly 28 rainy days.
- What is the air quality in Lake Toba in September?
- Lake Toba has a mean US Air Quality Index of about 32 in September.