Definitely heat – even cooking in a hot kitchen – and I have to wear my hair off the back of my neck and use cold water to cool my face and neck, or I get profuse sweating and even a sudden nose bleed. Also, more noticeable fluctuations in feeling changes in temperature even at night. I can be cold one minute and blazing hot the next. My temperature reading doesn’t change but I get really red flushing in my face when I get hot, exercise or even have a glass of wine (sigh – I miss having an occasional glass of wine). I also started getting purple hands (Raynaud’s disease) when my hands get cold. I live in a higher altitude in a cold climate and I have to have an air conditioner running and cooling scarf on my feet and legs in order to sleep in summer. I haven’t noticed cold affecting me at all.  I avoid trips to hot places during their hottest seasons. I will pay more attention to low pressure systems and my MG symptoms – I never considered there could be a correlation and we have a lot of pressure changes here. Thanks so much to everyone for sharing all of this great info – the more we understand about how environment and other conditions impact our MG symptoms, the easier it is to manage them and live our best lives!