What to Do in Bangkok in September: Rain, Floods and Tips

September weather: the peak of the monsoon

Source: 1991-2020 normals for the Bangkok Metropolis station of the Thai Meteorological Department (TMD), also used in our guide to the best time to visit Bangkok. Average relative humidity reaches 79%, the highest of the year: the heat is heavy and laundry dries poorly. It rains almost two days out of three, often in heavy late-afternoon downpours.

Extreme episodes do happen. In late September 2026, a tropical depression dropped more than 300 mm of rain in 48 hours on some districts, and the Bangkok Metropolitan Administration (BMA) declared all 50 of its districts a disaster zone on 26 September, with flights cancelled at Suvarnabhumi Airport in the following days. This is not the rule, but keep some flexibility in your plans, follow TMD and BMA alerts, and allow at least half a day before a flight, see Bangkok's airports.

Crowds and prices in September

This is the quietest month: foreign tourist arrivals in Thailand are at their lowest of the year (about 2.2 million in September 2025, according to the Ministry of Tourism and Sports). Hotels cut their rates and queues at the Grand Palace or Wat Pho are short. Choose a hotel near a BTS or MRT station, see where to stay in Bangkok, and check cancellation conditions. For spending, see the Bangkok travel budget.

Getting around when it pours

• Prefer the BTS and MRT to taxis: in a heavy shower, taxis and ride-hailing cars are scarce and traffic jams. See transport in Bangkok.
• Do not wade through standing water: it can hide open manholes and carry bacteria. Avoid getting your feet wet with an open wound.
• Reschedule excursions: floating markets and boats are disrupted by storms; check the day before.
• Keep a covered plan B: see what to do in Bangkok when it rains.
• Protect your phone and papers in a waterproof pouch, and see health in Bangkok for dengue.

Events in September 2027

Moon Festival (Mid-Autumn): Wednesday 15 September

The Moon Festival, or Mid-Autumn Festival, falls on Wednesday 15 September 2027 according to the Chinese lunar calendar. It is not a public holiday in Thailand. In Chinatown, bakeries sell mooncakes in the weeks before the festival: see our guide to Chinatown and Yaowarat.

Vegetarian Festival: 2027 dates to be confirmed

Chinatown's Vegetarian Festival, ten days of "jay" food on Yaowarat Road, is held in late September or October depending on the lunar calendar: 10 to 18 October in 2026. The 2027 dates have not, to our knowledge, been published; check the Bangkok Vegetarian Festival page before booking.

No public holiday falls in September: banks and government offices are open all month.

What to wear and pack in September

• Light, quick-drying clothes and a spare outfit.
• A poncho or a sturdy umbrella, more useful than a jacket, which is too hot.
• Closed sandals with a grippy sole that cope with water.
• A waterproof pouch and a protected backpack.
• Mosquito repellent.
• A light long-sleeved shirt for temples and air conditioning.

The best ideas for days out in September

• Museums: the National Museum, the Museum Siam and the Jim Thompson House; see also the museums of Bangkok.
• Galleries: see the contemporary art galleries.
• Thai massage and cooking classes: Thai massage; cooking classes.
• Shopping centres: ICONSIAM and Siam.
• Temples early in the morning, before the showers: Wat Pho.
• At the table: sheltered street food in the food courts, seasonal fruit such as mangosteen.

September 2027 at a glance

Going further

September follows what to do in Bangkok in August and precedes what to do in Bangkok in October. To compare every month, read the best time to visit Bangkok and the calendar of festivals and events.