When is Samonios in comparison to the Gregorian calendar?

The Celtic year started with Samonios. It is a fact non-discussed about.

The question is when the Celtic Year started? Notice, the Coligny table says nothing about that. The only argument for putting the start in June is that Samonios sounds like Summer. But naive etymology cannot be an argument in any discussion, except as a joke. If you want to take it as a fact, you must prove every change from the current state of word up to the probable source word. From Celtic into English. Have you seen those proofs? Neither did I.

We know, that existing Celt nations have their New Year Samain holiday at the end of October. Of course, the real historical holiday was connected to some Moon phase after the autumn equinox, not exactly to October 30 as it is now in some places. But that will give us a possible displacement of +- 28 days and won't reach June at any rate. If somewhen Celts did move the start of the year (such thing happened sometimes for some nations) and moved all months by three (the thing unheard of), there should be some mention of it somewhere, some legends, anything... Have you read about such move? Neither did I.

Already just before AD Celts' tribes covered all of Europe and Asia Minor. A coordinated calendar change in these times was already impossible. So, the change could happen either during the last 10 centuries, when Celts already lived in the same close area, or in the unknown ancient times, where all Celts lived together - before 1200BC. The first simply did not happen, we would know about such change in historical times. The second is possible.

But what could be the reason for such change? It couldn't be a state law - Celts hadn't got a state so long ago. So, it had to be a change in their religion. And it had to be a really great change. On the other hand, we have no knowledge of Celtic religion changes. Their religion remained the same. Celts=Celtic religion, druids and things. That religion was what made Celts Celts. So, if there was another religion before that one, neither later Celts nor we would recognize those people as Celts. Some predecessor tribe, probably.

On the other hand, before 1200BC Celts had no civilization and didn't have any need for a calendar. They had no agriculture yet. (It started at about 700BC in these parts)

Morals: Never trust in naive etymology.