There are a few who have tried it here but never well. The standard attempt usually involves changing over the elem level but not the middle and high schools so families who have kids at more than one school don't get breaks at the same time. So what happens is it tends to be initially popular with families who see the educational benefits but then becomes less so as the kids age and more families have to deal with the logistics of having their middle or high schoolers on a traditional schedule while the elementary schooler is on a year-round track. And part of the reason for the difficulty is that so few schools do this - if it were the norm, things like child care, enrichment camps and other break activities, sports schedules, etc. would fall into place, but as long as it is an unusual circumstance there will be challenges that come from being out of step with the norm.
As far as the weather issue I think that's another of those distractions that gets in the way of educational best practices. People would adapt and there are plenty of places that are fabulous in the winter, including some of the winter-sports destinations here in Michigan. Heck about 20% of our kids miss school at some point in the year to take a winter trip, mostly either to go to FL when it isn't terribly hot or to ski somewhere. And another huge chunk miss around this time of year for deer season trips that could be arranged during the fall break that is typically offered on a year-round schedule. Besides, on a typical year-round/extended-year schedule there is still a long break in the summer. The proposed schedule here cut summer break in half (5 weeks instead of 10 - all of July & first week of Aug), added a two week fall break, made Easter break a full two weeks, and extended existing Thanksgiving, Presidents' Day, and Memorial Day breaks to a full week each.