I don't like winter anymore, last year I spent 5+ week in Bs As just visiting my family/friends and it was like 2 weeks on summer, the day is too short
Check Lan, they usually have some good fare for JFK-MIA, sometimes cheaper than MIA-EZE. I had 2 weeks off starting this Friday and I didn't buy a ticket for $845 (6/16 to 6/29) because is winter

( $935-10% off sale -10% off coupon).
PS: don't you have AA or BA miles? JFk-EZE is 40k miles for RT ticket in spring break