Typhoon and monsoon season in Southeast Asia

Southeast Asia has two seasonal wind patterns. From about May to October, the southwest monsoon carries moist air off the Indian Ocean, bringing rain to Myanmar, Thailand's Andaman coast, Cambodia, Laos, southern Vietnam and the western Philippines. Rain usually comes as heavy afternoon or evening downpours rather than all-day grey, although weeks of steady rain do happen.

From about November to March, the northeast monsoon reverses the flow. East-facing coasts then get the rain: Vietnam's central coast from Hue down to Quy Nhon, the Gulf of Thailand islands such as Koh Samui, and Malaysia's east coast islands. Indonesia south of the equator, including Bali, has its wet season from about November to March. The practical upshot is that somewhere in the region is almost always in its dry season.

Typhoons, which are tropical cyclones in the western Pacific, form over warm sea mostly from June to December and travel west. The Philippines and Vietnam take the most hits; Thailand, Cambodia and Laos usually get the heavy rain from weakened storms rather than the wind.

Use the table as a planning guide, not a forecast. Seasons shift by weeks from year to year, and a single storm can close a coast for days in an otherwise dry month.

Sea travel stops first. In Vietnam, the Quang Ninh authorities suspend Ha Long Bay and Lan Ha Bay cruises when a storm or strong wind warning is issued, sometimes a day or two before landfall; boats return to harbour and overnight cruises are cancelled or refunded according to the operator's terms (check). In the Philippines, the Coast Guard stops sailings in areas under a tropical cyclone wind signal, starting with small boats and extending to larger ferries as signals rise (check). Andaman ferries from Phuket and Krabi to islands such as Koh Phi Phi and the Similans run reduced schedules or close in the southwest monsoon (check).

Airlines cancel flights into a storm's path, usually with a free rebooking window announced on their website. Airports themselves may close for hours. Domestic flights reopen faster than ferries, so if you are stuck on an island, a flight out is often the first way off.

Follow the national agency for the country you are in: PAGASA in the Philippines (which gives storms a local name and issues wind signals 1–5), NCHMF in Vietnam, and the Thai Meteorological Department. The Japan Meteorological Agency is the regional centre for the western Pacific and publishes track forecasts for every named storm. The US Joint Typhoon Warning Center (JTWC) issues its own forecasts, which are widely shared but may differ in strength and timing.

Look at the forecast cone, not just the centre line: heavy rain and flooding often reach far beyond the path of the eye. Your hotel reception and local news will also know when schools close, ferries stop and roads are cut.

Most travel insurance covers weather disruption only if you bought the policy before the storm became a known event, usually defined as the moment it was named or publicly forecast. Buying on the day a typhoon is announced rarely helps. Buy insurance when you book the trip, and read the section on natural disasters, missed connections and cancellation.

Keep receipts for extra hotel nights, meals and rebooked transport, and get written proof of cancellations from the airline or ferry operator. Some policies pay a fixed amount per hour of delay; others only refund prepaid, unused bookings.

Before: if you are on a low-lying coast, a small island or in a flood-prone old town such as Hoi An, move inland or to a solid hotel in a larger city a day ahead. Withdraw cash, since ATMs and card machines fail when power goes. Stock drinking water, snacks and a charged power bank, and download offline maps. Tell someone your plan.

During: stay indoors, away from windows. Many hotels close storm shutters or tape windows. Do not go out to look at the sea. Expect power and mobile data cuts for hours or days.

After: flood water hides open drains, debris and live cables, so do not wade or drive through it. In mountain areas such as northern Vietnam and the Philippine Cordillera, landslides can close roads for days after the rain stops. Wait for local confirmation that a road is open before setting off by motorbike or bus.

Rainy season has real advantages: lower hotel prices, fewer crowds at big sights, green rice fields and full waterfalls. Many days bring sun in the morning and one hard downpour in the afternoon. For many travellers, the smart move is to pick the coast that is dry that month rather than skip the region.

Plan with slack. Keep one or two buffer days before an international flight, avoid non-refundable boat trips at the end of your trip, and book flexible rates in storm-prone months. Trains and buses are often the more reliable backbone: Vietnam's north–south railway keeps running in most storms, though floods can suspend sections in the central region.