You ask: When is Thanksgiving?
I answer: It is on Thursday.
You ask: When is the holiday?
I answer: It is on Monday.

You ask: When is Thanksgiving?
I answer: It is in November.
You ask: When is the holiday?
I answer: It is in July.

Thanksgiving Şükran günü
Thursday Perşembe günü
Holiday Tatil, seyahat
Monday Pazartesi günü
NovemberKasım, yılın onbirinci ayı
JulyTemmuz ayı
English–Turkish Dictionary Table

I ask: What day is it today? 😇
You answer: ❓