Hard to say, but from your description, I'm guessing a slim rectangular hourglass like Angie and San and others here. I think you have a great figure - perfect for skinnies, and well, all sorts of fun fashions!
My advice would be to invest in one pair of dark wash skinnies, and one pair of something different. Perhaps dark wash or black bootcuts or straight legs, or even a pair of bootcut white jeans (which can be worn year-round, and for your clime in particular, are a must have).
Ignore the sale - that is what is throwing you. It is not a deal, if you don't need two pairs of skinnies and you really would rather have black instead of light blue!
I'm in a much colder clime and I live in skinnies tucked into boots throughout the winter. In warmer weather (spring/fall) I still wear them with ballet flats (not converses - I am told this is a teenybopper look), but also wear straight legs and bootcuts and trouser cuts too.
I do think skinnies - if they flatter - are worth owning even if you can only have two pairs, and you are in a warmer clime where you don't wear boots all that often. My reasoning is pretty simple: they are THE fashion right now! Instant trend update. I don't think they'll be going back out of fashion anytime soon either.
So go for one pair of trendy skinnies, and one pair of something in a more classic cut, like bootcuts. Do consider white instead of black denim.
As for the boots question, yes, boots are more warm than sneakers and socks. I am finding this year that I can only wear tall boots comfortably when the temps get in the 40s and below. I do not know how others can wear them in 50 and up temps!! But that may just be me. I run hot lately, thanks to pre-menopause.
If you do invest in boots, give the peep-toe boots a try! You are in the best clime to pull something like that off.