hello!

Can some one explain when what time the exchange rate change in Thailand?

Just go daily exchange rate from Thaivisa SMS shows tomorow euro 39,3 and pound 45 Thb going down today half bath , but visa website show still the better rate?

how it comes that the thai banks know the next day exchange rate earlier then other country's?

The exchange rates changes several times per day depending upon how active the forex market is

The Thai banks know what the exchange rate is for the next day since they close before European or American banks open

You should be getting your rates from bank web sites not Thai Visa or Visa International since you will most likely be getting your exchange at a bank in Thailand

For daily fluctuations see this Siam Commercial Bank web page, just click on the time on the top to obtain this type of detail:

http://www.scb.co.th/scb_api/index.jsp