StormGrid shows where it is raining across the United Kingdom right now, using the Met Office national radar composite. Watch the last few hours animate to see whether a shower is heading towards you or away, search any town or postcode, and check official Met Office warnings and Environment Agency flood alerts on the same map.
Real lightning strikes are shown as they are detected, and they are free for everyone. So are the radar, the animation, the warnings and the flood alerts — there is no account needed and nothing to install.