Helena, six or so years ago when I was going through the worst of my hot flashes while also sharing space with a co-worker who, though delightful in every other way, ran very very cold (and thus wanted our workspace MUCH warmer than I did), I asked on here what was the lightest possible layer I could wear under my clothes and still decently strip down to for a few minutes until the flash passed. Someone suggested the Uniqlo AIRism t-shirts and that suggestion served me well.
I agree with everyone that it's fascinating how much this all differs from person to person. One of my close friends never had any perimenopausal or menopausal symptoms, not a hot flash, not a night sweat, not a mood swing, nothing. But she never had any significant PMS either, so I'm not sure if there's any correlation?