Only when I remember which can be week's personally never had a problem in 20year's and to be honest don't have time to change everytime especially when at work but we are all different and you should use how you feel is right for you
Mine definitely goes down during hot weather, went to Turkey last year was in the 90's all week perfect to slightly low bs on all inclusive too (didn't go mad tho couple more ice creams perhaps!!) I think I need to move to a warmer climate for my diabetes that's my excuse anyway