Sok, you don't have facts on your side on this one: @<a href="#" class="seekto" data-time="1262">21:02</a> low tourist seasons exist in both Cambodia and Thailand, and occur about the same time in an average year, although they are slightly different. All you need to do is use time series decomposition techniques to split the Min of Tourism monthly time series and extract the seasonal factors. For Thailand, check the study by S Intarapak et al (2022).