Looks like Lughaidh is correct about the capital
M on
Mhí (according to Learning Irish), and
Márta is masculine in Connemara too. Fixed above.

Hmm, interesting. TYI doesn't bother with a capital. No mention in GGnamBC or An Caighdeán. Guess it must be optional. Personally, I look on it as part of the name of the month, so the capital makes sense.
Working from WFM's list, and filling in the gaps from other sources, we have:
1.
Eanáir or
Mí Eanáir or
an chéad mhí den bhliain2.
Feabhra or
Mí na Feabhra or
Mí na Féile Bríde3.
Márta or
An Márta or
Mí an Mhárta4.
Aibreán or
An tAibreán or Mí Aibreáin5.
Bealtaine or
An Bhealtaine or
Mí na Bealtaine6.
Meitheamh or
an Mheitheamh or
Mí an Mheithimh7.
Iúil or
Mí Iúil8.
Lúnasa or
Mí na Lúnasa or
Mí Lúnasa9.
Meán Fómhair or
Mí Meán Fómhair 10.
Deireadh Fómhair or Mí Deireadh Fómhair 11.
Samhain or
Mí na Samhna12.
Nollaig or
Mí na NollagWeeFalorieMan wrote:
Is é an lá inniu an Aoine ...
According to TYI, you can also just say
Inniu an Aoine ... for that, and in Connemara it would be
Inniu Dé hAoine ... (whereas
Dé is only used adverbially in Munster.)
WeeFalorieMan wrote:
How would you say: To-day is Friday May 31st 2013
"Today is Friday 31 May 2013."
Inniu Dé hAoine/an Aoine an t-aonú lá dhéag is fiche dhá mhíle is a trí déagLooks like it is also
an t-aonú lá is fiche for "the twenty-first" (not
an chéad lá is fiche*).
