Will be traveling from Dublin to Cancun via JFK NewYork via Dallas FW. Comming from NewYork to Dallas and have only 1 hour to another flight to Cancun Mexico at 3 of September. Will this be enough time?

You might have a better response on the Air Travel forum page.

Will you have to clear immigration/customs at JFK? If yes, then it's not enough time.

If there's a way you can just pass thru the USA without having to do that, then maybe.

Sounds like you have a one-hour layover in Dallas, not New York, so yes, I think it's doable.

You can't transit in the US without going through Immigration and Customs. In this case that will happen in NYC. I hope you have at least a 3 hour layover there.

As for 1 hour in Dallas - is this all on a single ticket? If it is you are protected and if you mis the flight they are required to put you on the next one with an empty seat. If these are separate tickets and you miss the flight you will be considered a no show and have to buy a new ticket at the walk up price.'

If the latter is the case I would change flights to have a much longer layover in Dallas.

Sorry - don't see where you are from but you will need a US visa with multiple entries in order to do this trip. Not sure if you need ESTA or an actual visa.

Dublin, as stated in the post, so ESTA should suffice.

Dublin airport offers preclearance (not sure if OP's flight is one with preclearance). If on a flight with preclearance OP will go through customs and immigration in Dublin and arrive as a domestic passenger at JFK.

Dublin, as stated in the post, so ESTA should suffice.

Being eligible for an ESTA depends on nationality. I don't see any mention of the OP's nationality.

Is it the DFW-CUN flight you are asking if an hour is enough? An hour is not enough at any of your connection points.

If you have an ESTA, it takes 10-20 mins to get thru immigration at JFK if you use the kiosks. If you prefer to stand in line, it can take hours. Customs and baggage can take forever to get through. And then a change of terminal perhaps?