How do I make something happen once every 3 nights?

So I am trying to make a part emit particles but I want it to emit it every 3 nights, how would I do that?

First of you would need to have a day and night script. To do that create a script in ServerScriptService that makes the lighting's ClockTime constantly go up a bit and resets the ClockTime to 0 when ClockTime reaches 24.

Second get an IntValue in ReplicatedStorage call it Nights (you can actually call it whatever you want)

then a script that changes the IntValue every time the ClockTime goes back to 0 and resets the IntValue to 0 when it wants to go pass 3.

and finally another script in ServerScriptService. Make it so that every time the IntValue reaches 3 you activate a Particle Emitter.

because this ain't a request site, I won't give any scripts, therefore this is the most I can tell you.