Ireland probably had something equivalent to the Coligny Calendar at one point in its history due to the presence of some repeated turns of phrases found in the Irish sagas, but by the historic period any record of it has collapsed. What we do have are references to four festivals, Lughnasadh, Samhain, Imbloc, and Beltane. Now, we know very little about the majority of these asides from their names, and anything you read about them online will be exceptionally dodgy. What we can say for sure is Lughnasadh was held on July 31st - August 1st and was probably something to do with the harvest or collection...