Is it normal for my 90-day Non-Immigrant O visa application to take longer than expected due to the Songkran holiday?

Surprisingly (or not) this actually happens quite a lot (especially at the smaller immigration offices) for both initial 90 day Non-Imm visas and year extensions which require an under consideration period.

That's because these applications need to go to the division headquarter to get approval before being sent back to the issuing office

I tell people, IF they took your application, charged you the 2000baht, gave you a receipt, with a report back date, you WILL get the 90 day Non-Imm visa.

I have never seen nor heard of anyone applying for the initial Non-Imm visa who did not receive it (even if the report back date had past)..

I know that it makes you feel uncomfortable but not a lot you can do other than wait it out.. With the Songkran holiday I'd say just stay in contact with the immigration office report back when they told you to..

Wait it out, don't panic, it's part of the process...