I find damp - in hot weather or in cold - seems to make my symptoms play up (so should move from Britain really, shouldn’t I?). So far, I don’t mind heat by itself, but dislike either warm and humid OR cold and damp.
I’ve never found any scentific explanation why damp might affect it - other than perhaps just the psychological effects of miserable weather. But interestingly, when I saw a traditional Chinese acupuncturist (he wasn’t Chinese, but that’s beside the point), he informed me that, unsurprisingly, traditional Chinese medicine doesn’t recognize any such thing as “MS” (it wasn’t “discovered” then - and is rare in Chinese people anyway). Instead, it views all bodily ailments as the product of imbalances between the elements.
The diagnosis is individual to the person, not the disease, so not everyone with MS would necessarily get the same Chinese diagnosis. But for me, it was an excess of damp! That’s not to say he didn’t believe or accept the Western diagnosis - it’s just a completely different way of looking at things. Although I didn’t persevere with the acupuncture, the “damp” diagnosis does fit very well with my everyday experience - I hate and dread “damp”, but feel better when it’s dry.