He'll be miserable at first. Heh.
I remember my Long Island friends (husband and wife) when we first reported to Fort Bragg, North Carolina, in June of 1986. They absolutely could not stand the heat. Other than one autumn and one spring in Northern Virginia for some training courses, they'd spent their entire lives in New York or Germany, to that point. Kind of like Kelly's life up north thus far.
But by the second summer, they were old hands. The wife still didn't like it, but the husband didn't mind. I think because he was outdoors almost all the time working, he acclimated much quicker to it than she did spending much of the day in air conditioning.
Kelly will be outdoors a lot, so he'll get used to it over the first summer. By year two, he won't think twice about it.