Every year, our planet Earth crosses the orbital path of Halley’s Comet in late April and May. Bits and pieces from this comet light up the night-time as Eta Aquariid meteors. This shower is said to be active from April 19 to May 20, although Earth travels most deeply into this stream of comet debris around May 5 or 6.
The best time to see the meteors will be late tonight, Wednesday 5h May, or very early tomorrow morning when the sky is at its darkest. Even if you miss it this evening, you’ll have a chance to catch it tomorrow night.