What to expect . . . High Season coincides with the best weather, so From mid November through to March you can expect plenty of sunshine and hardly any rain. You can also expect strong winds from the northeast in November & December which cool things down a little.
The hottest time of the year is March/April. From May through to October it’s the season referred to as one of the following: rainy season / green season / low season or simply the season to shelter indoors and play with your Nintendo for 5 months. Whatever you call it, there will be rain most days. However, this is often just in isolated showers during daylight hours. Most of the heavy rain is overnight. So you will see the sun, but can’t guarantee how much or on what days.
When to Visit: Ideally when it isnt raining, unless you just want a quiet escape from everyone – in which case Koh Chang in July is ideal. May & November are often pretty good months for visiting as they often combine quite a lot of sunshine with low season prices and very few . Plus most of the tour boats and dive schools are up and running so activity wise there are things to do.
This area of Thailand is one of the wettest in the country but that doesn’t mean that it rainy constantly during the rainy season. The majority or rainfall comes in the form of storms or very heavy rain showers which often last only 30 minutes per day before the sky clears and the sun comes out. So having an entire week of grey, overcast sky and no sunshine is quite a rarity but if you are visiting the island in the Western summer holidays, you aren’t going to be able to guarantee that you’ll come home with a deep tan.
How wet does it get?: The north of England averages about 800 – 1000mm of rain every year. This sounds a lot – but it isn’t, it’s roughly what Koh Chang gets every month in June, July, August and September. But as I mentioned above, the rain is in heavy tropical downpours rather than drizzling for days as it does in the UK & northern Europe. In total Koh Chang receives around 4,000mm of rain each year, most of it falling in these months.
From my unscientific observations of recent rainy seasons I’d say that the best of the rainy season weather is in the last two weeks of August, the weather in this period has been good in 2004,05,06,07 & 08.Not much rain, some cloud but a lot of sunshine and deserted beaches. Whereas mid to late of September has been the time of year which consistently has very heavy prolonged rainfall.
The data below is from the Thai Meteorological Office. In reality, I don’t think it is as wet as the offical stats make out, maybe that’s an upside of global warming.
|No. of very
rainy days >35mm
Temperature: It’s around 28-30C every day. A little warmer in March and April, possibly up to high 30′sC. And in December the mercury will struggle to get to 27/28C during the daytime, before plummeting overnight to around 15-18C. (If you have never experienced a night at 15C, then believe me, it is cold. you’ll need to pack a long sleeved shirt if you plan on going out on a midwinter’s evening.)
Humidity: It’s a tropical island full of trees, so you’ll sweat a lot regardless of what time of year you visit. That’s really all you need to know.
5 Day Weather Forecast: Kwikcast.com
Excellent Short Range & Long Range Forecast For Koh Chang: Koh Chang on Norwegian Met Institute
Past Weather From August 2006 to Today: Weather Updates