Northern Thailand has a typical monsoon climate, but since it lies well North of the equator    (between 17 and 20 degrees North ), it does experience marked seasonal temperature variations.

The ‘wet season’ monsoon rains start in late May or early June and continue until October. Temperatures in the lowlands are around 32 degrees C in the mid-afternoon, falling to a minimum of around 23 degrees C at night. It rains on most days but rarely continuously. A typical day will dawn bright and sunny, clouds build up during the afternoon leading to heavy rain for an hour or two, frequently followed by a sunny evening. In August and September, typhoons sometimes occur ( although rarely severe ), with heavy rain, thunderstorms and high winds for three of four days.

In the ‘cool season’ from early November to February, humid tropical air from the Indian ocean gives way to cold, dry air originating in Central Asia to the North. The sun is still high enough to send temperatures above 28 degrees C during the afternoon, but following sunset the temperature drops rapidly, frequently to below 10 degrees C., so that early mornings are delightfully cool and misty. The sky is generally cloudless all day, and rain is very unlikely - perhaps one shower a month. From December, many of the trees lose their leaves as a protection against drought, and the lush greens of the countryside give way to sombre browns.

The ‘hot season’ is mercifully short - from mid March to late May. As the sun climbs higher in the sky, daytime temperatures approach 40 degrees C., and humidity increases, making any exertion difficult.

During this season the jungle is burnt off to prepare for next seasons planting, so the hills are  very smoky and dusty. The start of the rains, ( usually a massive thunderstorm ) brings relief as the temperatures drop. Temperatures decrease and rainfall increases with altitude, so the ‘wet season’ is significantly wetter and cooler in the hills. In the ‘cool season’, temperatures below freezing at night are not uncommon above altitudes of 1500 meters.