July holidays...
July 13, Wednesday, Asanha Bucha Day
July 14, Thursday, Khao Phansa Day (Buddhist Lent)
July 15, Friday, Extra public holiday
July 28, Thursday, King Vajiralongkorn's Birthday
July 29, Friday, Additional special holiday
All above dates includes immigration, land transport and other government offices are closed.
13, 28, 29 only are bank holidays. Main branches closed, satellite offices such as in malls normally open. 13, 14 - Buddhist holidays so dry days (Not about possible rain, but no sales of alcohol).
If your Admitted or permitted to stay is on one of the closed days and you can not manage to go before that day, you can go the first working day after. You may get an extra stamp with overstay but no fines due to closed for holidays.
Take care