Wearing sunglasses during winter in Toronto was (and I assume still is) a totally normal thing (although frozen plastic didn't feel so good on the face, so when it was -21°C and blizzarding I'd leave them at home. Don't get me started on frozen eyeballs). Wearing sunglasses in England, at least where I live, when it's sunny but a bit cool out will get you stares; there seems to be an assumption that when the air is less than warm - sunny or not - sunglasses stay at home. And I live by the beach!
I am an all-year-round sunglasses wearer. Not because I am a rock star, always hung over or get punched in the face a lot - yes, the latter two have actually been assumed by strangers. I have had to explain to people I don't know that I can't even drink enough to get a hangover in the first place because alchohol makes me so sleepy. And I had to lift my glasses to show a guy at the metro station that I wasn't bruised undermeath. Why? Because I was wearing sunglasses when it was overcast or cold out and apparently that blows some people's minds. I wish I was making this silly stuff up but no, I have to deal with this. I never leave my house without my sunnies because I have extremely sensitive eyes; I've been checked regularly since childhood and there's no medical reason, I'm just lucky! If I don't wear some protection I have to squint to see, I get headaches, my eyes sting and begin to water and well, I just don't look good either and when that happens everyone suffers.
Here are some good reasons to wear sunglasses with full UV protection, year-round:
• Protect from the harmful effects of ultraviolet exposure which can include premature aging, cataracts, skin cancer, burns on the eye itself, and other nasty things
• Reduce or prevent headache: intense sunlight can cause migraine, tension, and other types of headaches
• Help the eye retain moisture: by blocking the sun’s light and heat, sunglasses can help keep the eyes moist by lessening the evaporation of tears
Sunglasses should also be worn when taking medications that induce photosensitivity, such as antibiotics or anti-inflammatories, so you don't get headaches and eye pain. And of course they look great, too! It's a win-win. I'm looking at some new frames to liven things up a bit and I have my eye on these black and blue Pradas from Sunglasses UK - they'd be a nice change from the tortoise shell pair I've been wearing which suit me, but aren't as cool as these: