How to use the calendar
The box at the top shows the Next peak: the name of the shower, its full date and how much of the Moon will be lit that night. The table below lists all 10 showers in the order of their next peaks, starting with the one coming up. For each one it shows:
- Peak: the date of maximum activity, and Active: the window when the shower produces meteors.
- ZHR: the zenithal hourly rate, explained below.
- Radiant: the constellation the meteors seem to come from.
- Parent body: the comet or asteroid whose debris causes the shower.
- Speed: how fast the meteors hit the atmosphere, in km/s.
- Moon at peak: the percentage of the Moon that is lit on the coming peak night.
Click a shower’s name for a full guide, such as the Perseid meteor shower or the Geminid meteor shower.
What the ZHR means
The zenithal hourly rate is the number of meteors a single observer would see in one hour under a perfectly dark sky, with the radiant straight overhead. Real conditions are never that good, so you will usually see fewer: light pollution, a low radiant, haze and moonlight all cut the count. A ZHR of 100 might give a few dozen meteors an hour from a dark rural site and only a handful from a city.
Why the Moon matters
Moonlight brightens the sky and hides the fainter meteors, which are the majority. A shower peaking near new moon can be spectacular, while the same shower near full moon may show only its brightest members. That is why the table shows the Moon’s illumination at each peak. For the dates of new and full moon, see moon phases.
Where meteor showers come from
Comets, and occasionally asteroids, leave trails of dust and grit along their orbits. When Earth passes through such a trail each year, the particles enter the atmosphere at high speed and burn up as meteors. Because all particles travel in parallel, their paths seem to fan out from one point in the sky, the radiant, which gives each shower its name: the Orionids appear to come from Orion and the Leonids from Leo. Halley’s Comet is the parent of two showers, the Eta Aquariids in May and the Orionids in October. To learn more, read what is a meteor.
Tips for watching
Find a dark place away from streetlights, with a wide view of the sky. Dress warmly, even in summer, and bring a reclining chair or a blanket. You do not need to look at the radiant: meteors appear all over the sky, and those further from the radiant often have longer trails. Check the weather, and plan for the peak night and the night before or after, since rates are often good on either side of the maximum.