Weight gain in a humid climate

About 6 months ago I moved from the high Rockies of Colorado to Hawaii. In Colorado I weighed 122lbs in the morning and within weeks of moving to Hawaii I gained 5-7lbs. I am now at 130 in the morning. I workout and I eat healthy. Mostly low carb paleo diet with a free day every couple of weeks. I was wondering if the change in climate- a very dry high altitude cool climate to a very hot humid sea level climate could have added any weight in the form of water weight? I can't figure out where the extra weight has come from- I continue to eat healthy and exercise. Could it be age related? I just turned 35 or perhaps the Hawaiian diet adds more carbs/sugar in the form of fruit? (I don't eat processed sugar but will eat fruit occasionally). I'd like to get back to my Colorado weight - is that realistic or could the environment actually add weight? Thanks for your time :-) Mahalo