Over the past few years, I've noticed the weather has a direct impact on my writing patterns.
Sun. I wake up early (like, 5:30 am in the summer), raring to go. I love watching the early morning sun as the streets come to life. Mornings are productive with lots of words on the page but by lunch I'm chafing to get outside. Living in London you quickly learn to take advantage of the sun while it lasts. Not to mention the afternoon sun pouring into my office makes it downright sauna-like.
Cloud. The most common, especially in winter. I've never known a grey like a London sky in winter -- my husband describes it as 'rat grey' (apparently they have a word for this in Arabic). I work slowly and steadily and while I may not achieve as much as my sunny streaks I usually reflect more on my plot and characters.
Rain. I spend the morning feeling smug and cozy in my flat, watching others struggle on the street outside (nice, I know). I work in spurts between downpours, then get the irresistible urge to curl up on my comfy bed with a book --- usually ending in a nap.
Snow. Rare, very rare, in London. Chances are if it's snowing, I'm not working. I'm too busy checking Twitter to see what part of London has imploded under 2 cm of snow or listening to how the end of the world is nigh since we don't have enough grit.
How does the weather affect your work?