I know, I'm supposed to be Mr. Buddhist here and "it is what it is" and all that, but damn, Sam, there's one thing that really can ruin an MS person's day (aside from falling, forgetting where your house is, and who is that person is smiling at you?) and that's heat. In fact I'm writing this in the air-conditioned bedroom far from the kitchen where its only 86 degrees. Now there are plenty of good places to get info on MS and heat like here. While Julie in the article talks about how MS sufferers have to resign themselves to sitting in dark rooms typing on their laptops, hoping the air conditioner will keep cranking, and we sit reading books (honestly not that hard), we miss the bliss of the outside.
Back when my hair was short, or rather long, or really, back when I had hair I'd be outside in this weather playing baseball for hours, and later I'd watch other people play baseball, and then go home, grab a shower and a cold Coke and watch baseball on TV. Now I can barely make it watching one game before I doze off.
But like I'm supposed to say, it is what it is. Looking at the other world, there's been a few studies that may link weather and bipolar disorder, but nothing definitive, so you can Google that at your leisure. What matters is that I can get crabby (or crabbier) in this heat. I am fortunate that my wife is also not a big heat person.
The only reason we like summer, aside from baseball, is that the next season is autumn.