Go through your results for flights to Chiang Rai in Thailand with Netflights.
Flexible on dates? Conducting your search by month allows you to compare prices to Chiang Rai throughout the year. Accommodation prices will also be higher at this time of year.
So, if the flights to Chiang Rai don't work for you, you could always try searching for flights to other airports in Thailand.
For even more options, check what other airports you could fly to Chiang Rai from. You might be able to make a saving by going from a different airport or city.