Heat and flare up

Having a terrible flare up and more time of work. Completely exhausted, can barely walk and psorasis has spread to new places. I had this last year in the heat and remember the Dr telling me that heat can be just as bad as the cold. However I seem to have other non medical people (uh hum work and friends) commenting about how I am wrong and shouldn't flare up in the summer. I just wondered on all your experiences. Thank you