"We have had a lot of rain this month."

Translation: Nous avons eu beaucoup de pluie ce mois-ci.

[r.o.c.]

Nous avons eu beaucoup de pluie ce mois-ci.

If there is ce meaning this before mois, why is there another ci after mois?
When should i apply this?

[Sitesurf]

If you say "nous avons eu bcp de pluie ce mois-là" it means that you are referring to a past time, while "ce mois-ci" is about the current month at the time you speak.

[r.o.c.]

merci bcp sitesurf, je t'en remercie

[dbrockertactor]

Why isn't cet mois-ci acceptable? I can't seem to figure out why "ce" and "cet" are sometimes both allowed and sometimes not.

[Sitesurf]

because ce is used in front of masculine words starting with a consonant and cet in front of masculine words starting with a vowel or a non aspirate H:

ce mois-ci

cet arbre

cet homme