Another issue to keep in mind is that airlines will refuse to transport dogs if the temperature at embarkation OR destination airport is below 45 F. or above 85 F.
I just had an immense hassle with American Airlines, bringing two dogs back to Argentina in early March. The temperature at JFK airport was 39 F., and AA rudely informed me, 'Go home, you ain't flying.' Next day I returned, same problem. But this time, a helpful manager informed me that a special document called 'Certificate of Acclimatization' signed by the vet could allow the 'temperature window' rule to be waived.
I had to call the vet from the ticket counter and get this certificate issued and sent to AA by fax -- two hours of last-minute "tramites." Then you have to unpack the dogs from their kennels and hand-carry them through the TSA's metal detector or scanner. AARGH!
With Argentina and the U.S. being in opposite hemispheres, probably the best idea is to schedule your trip in spring or autumn, when neither end of your travel itinerary is at extreme temperatures. Suerte!