Riding a Scooter in Chiang Mai Rainy Season

Chiang Mai’s rainy season runs from May to October. The roads are passable — thousands of riders do it every year — but rain changes the physics of every corner and every stop. Here is what actually changes and how to adjust.

When rainy season runs

Month	Character
May	Hot, afternoon thunderstorms begin — roads still mostly dry
June	Frequent afternoon rain, roads wet most days
July–September	Peak rainfall, flash floods possible
October	Rain tapering off, roads still wet

The green season (as it is also called) brings the landscape to life and makes Northern Thailand look its best. But it requires adjusting how you ride.

What rain actually changes

Grip

Reduced on every surface, especially:

• Road paint — lane markings, painted arrows, and painted edge lines become extremely slippery when wet. This is one of the most dangerous surfaces in Chiang Mai rain and surprises most riders. A painted arrow in the middle of a corner is a genuine hazard.
• Metal surfaces — drain covers (manhole covers), steel plates on road repairs, any painted surface
• Leaves and mud — common on mountain roads
• Gravel and sand — accumulated at corners and junctions during dry season, becomes slick when wet

Braking distance

Braking distance increases significantly in the wet. Apply brakes earlier and more progressively. On a scooter with CBS (Combined Braking System), let the system manage front-rear distribution. On a scooter with ABS, you can brake more firmly without locking the wheel — ABS is a genuine safety advantage in wet conditions.

Visibility

Heavy rain reduces visibility for you and for other drivers. A visor without anti-fog treatment fogs immediately when you stop at a junction. Headlights of other vehicles are harder to see through rain.

Road closures and flash floods

Low-lying roads near rivers can flood quickly after heavy rain. Route 107 between Chiang Mai and Pai passes several river crossings. If water is running across the road, do not attempt to cross — the depth and road surface under the water are unknown.

Mountain roads can develop landslides after heavy sustained rain. Check local conditions before heading into the mountains. Some mountain roads are reduced to one lane or temporarily closed after major rain events.

How to prepare

Before you ride

• Apply anti-fog spray or wipe to your visor before departure
• Ensure your headlight is working — always on, even in daylight
• Check tyre tread — bald tyres have no grip in the wet
• Pack rain gear in your bag

What to wear in the rain

• Rain jacket over your clothes — not a poncho. A poncho billows, catches wind, and can wrap around the handlebars or wheel. A proper rain jacket that fits over your clothing is essential.
• Waterproof bag for your belongings
• Closed shoes — wet sandals or thongs offer no protection in a crash

The anti-fog habit

At every stop — a coffee shop, a fuel stop, a viewpoint — wipe your visor dry before you set off again. A fogged visor on a wet road is nearly blind.

Mountain roads in rain

Mountain roads in the wet are genuinely dangerous. Before you head up:

• Check the weather at your destination — mountain weather changes faster than city weather
• If thunderstorms are forecast, delay or cancel the mountain trip
• If rain begins while you are on a mountain road, pull over and wait for it to pass if possible

When riding in the wet on mountain roads:

• Reduce speed by 30–40%
• Increase following distance
• Treat every painted line as slippery
• Do not use the front brake aggressively in corners — rear brake only, keep the front wheel straight
• If you feel the rear wheel losing grip, straighten the bike immediately and brake gently

After the rain

If your scooter has been sitting in heavy rain:

• Check the brakes before you set off — wet road grime coats brake pads and reduces bite
• Dry your helmet properly before storing it — wet padding develops mould within days and the smell is difficult to remove
• Check the seat is dry before you sit

Green season specifics

The green season (May–October) is when the landscape is at its most beautiful. Doi Inthanon and the surrounding mountains are green and the waterfalls are flowing. The trade-off is:

• Roads are wet more often than dry
• Mountain roads require more attention
• Daylight hours are slightly shorter (sunset around 18:30 in June–August)
• Fewer tourists means quieter roads but also thinner rental fleet availability

Sources

• Chiang Mai Ambassador, “Chiang Mai Driving Tips” (chiangmaiambassador.com, accessed 2026-04-27)
• Chiang Mai Locator, “Traffic rules in Thailand” (chiangmailocator.com, accessed 2026-04-27)