It would be a good idea if the clothing industry just accepted that here in the UK we rarely experience a proper version of 'summer'. For most of the year we have to protect ourselves from the elements, which are often as furious in spring/autumn as in winter (let's be honest), yet when summer technically arrives (ie, May onwards) the stores stock up on stupidly unrealistic, aspirational crap which is more suited to California than Manchester, iyswim?
We are supposed to flip from pale and untoned straight into tan and lithe at the drop of a hat. And every year we fall for it - all over again.
I think that in Britain we have to dress intuitively, rather than ideally. Our wardrobes need to be constantly prepared for irrational temp/weather changes, day by day, hour by hour. Sleeveless frocks are only rarely necessary (parties, very hot days, etc) and should probably - logically- be in the minority.....but no, not so.
It's either sleeveless or those flammable balloon sleeves, or 3/4 shit that gets bunched up to the armpit when to attempt to put on a jacket.
And even if you have good arms, sleeveless is still a pain in the arse because 9 times out of 10 you have to locate a cardi or jacket to counteract the cold, which will generally, unless you are very fortunate, destroy the look of the dress.
So you've got the industry churning out crap which imitates Hollywood that hardly any of us can actually wear.