RAINY SEASON
Late May - mid October, with September the wettest month. The temperature range is 22 - 35 Celsius. The first regular thunderstorms come in late May and increase in frequency until they become daily July - September. By mid - late October the rain stops. In November there are normally one or two final rainstorms. Keen bikers that enjoy the challenge of riding on muddy roads should consider touring in late September- October.
The rains are usually tropical thunderstorms of short duration 1/2 - 2 hrs. Once a month July - September there is likely to be a period of bad weather, with steady rain for several consecutive days. Unless you like the thrill of riding in the rain on slippery roads, this is an unfavourable time for enjoyable riding.
Rain wear two piece light weight water proof suits are the best protection against the rain in the tropics. Riders should bring their own waterproofs as the only local rain wear - flimsy plastic ponchos - available do not provide adequate protection. I do not normally carry my waterproofs from mid December - January - March.
Rough rain guide - consider this for predicting where the rain's coming from & where to ride and avoid it. The rain comes from the sea & in North Thailand that means from either;
The Bay of Bengal & Burma way = the west-south-west
The Gulf of Tonkin / China Sea & Vietnam way = east-north-east
So if there’s a lot of rain around you just need to know where it coming from – either the West or the East.
If it’s coming from the west-south-west, then there’s a chance that the further east you go the less chance of rain. So if you’re starting from Chiang Mai then head towards the Laos border & Nan to get a dry ride.
If it’s coming from the east-north-east, then there’s a chance that the further west you go the less chance of rain. So if you’re starting in Chiang Mai then head west towards the Burma border & Mae Sarieng / Mae Hong Son to get a dry ride.
For help deciding where the rain is coming from take a look at these satellite pictures.
1.
Thai Met Office.
2.
The Weather Channel.
I always check these out when I’m off on a longish ride 3-4 day plus ride & worry about where the rain might be coming from. The important thing when looking at the pictures is to see where the rain is coming from - the west or east. Then make your plan.
If want to know whether the Mekong might flood check out
Mekong river water level & floods.
In the
wet season many National Parks in Thailand are closed.