I'm not a big fan of the sun, but when it isn't there I miss it. Trying to catch some sun:
Type "light" into the visual thesaurus.
Chill out on the Tate Modern's concrete beach. It was crowded when we went, yesterday (we even ran into a friend) but the monochromatic light, sweet-scented mist and sheer vastness hushes and calms, so it doesn't feel crowded. In front of the huge sodium-light sun people lie down, sleep, sunbathe, stare up at the reflecting sky scattered with distant figures making faces and shapes and occasional flash-bulb sparkles while frequency-smuggling toddlers scamper around flashing penlights, bike lights, car lights. When you get bored of the public beach, there's a community centre upstairs (£6/£4 entry) with ping-pond (two ping-pong tables fused with a lily-pond bursting with fragrant lillies -- eight bats, no rules), a slightly dangerous french billiards variation (points for getting hit by the pendulum!), talking ant-hats, a frisbee and wendy-house combo, a reading-room full of casually-translated german philisophy (I took away a handout about the communities of hapless people) and a surprisingly pleasurable set of sliding mirrored doors, which really do close with a self-satisfied sigh. Also a space-shed made of coat hangers which was trying to talk to the real thing, though (unlike the others I've mentioned) you weren't allowed to touch that.
Visit Cowley Road Beach.
Stare at the real thing in the SOHO gallery.