When planning a holiday, getting your timing right is important and if you're wondering when is the best time to visit Thailand and the answer is quite simple - there really isn't a 'bad' time to visit. As far as the weather is concerned, there aren't really any extremes so it's generally a good time to visit year round. However, as a tropical climate the rainy season from July to October can put some people off. Although it's important to remember that the rain passes quickly and actually helps to cool down the temperature.