That's an interesting observation, Ken. I have not found any difference in loading using cloth patches with any weather extremes - except for severe cold - ie: minus 30 and colder.
Seems to me Taylor's first .62 Hawken got crunchy after a few shots using leather for patches - course, who knows what lube he was using- probably crisco shortening smeared all over. That means his bore's condition was changing shot to shot - not a recipe for accuracy, but for hunting larger game with large X rings, I suspose it's OK.
Today, I really don't see a need to use leather, with it being the most expensive and least accurate method of loading.