Why meteor rates are never as high as advertised
The famous "100 per hour" figure for a big shower is the zenithal hourly rate (ZHR) — a benchmark measured under perfect conditions: the radiant straight overhead, a pitch-black sky and no Moon. Real skies pull it down, often by a lot.
What actually sets your rate
Three factors decide how many you really see:
- Radiant altitude. The higher the shower's radiant climbs above your horizon, the more meteors clear it. Near the horizon most are hidden below.
- Moonlight. A bright Moon erases the faint trails, which are the majority.
- Sky darkness. City light pollution can cut a dark-sky rate to a fraction.
The calculator above works all three out for your latitude and date, hour by hour.
Timing the peak
The radiant rises and sets like everything else, so it usually sits highest in the hours before dawn — which is why seasoned watchers set an early alarm rather than going out right after sunset.
Frequently asked questions
What is ZHR (zenithal hourly rate)?
ZHR is the number of meteors a single observer would see per hour under ideal conditions: the shower's radiant straight overhead, a limiting magnitude of 6.5 (very dark sky) and no Moon. It is a benchmark, not what you will usually see.
Why do I see fewer meteors than the advertised rate?
Three things cut the ZHR down: how high the radiant sits above your horizon (lower means fewer), moonlight washing out faint trails, and light pollution. The calculator combines all three to estimate your real rate through the night.
When is the best time to watch a meteor shower?
Usually the hours before dawn, when the radiant climbs highest and your side of Earth faces into the stream. The tool shows the rate across the whole night so you can pick the peak window.
Does the Moon ruin a meteor shower?
A bright Moon near full can hide most fainter meteors, sometimes halving the visible rate or worse. A new Moon, or a shower peaking after the Moon sets, gives the darkest sky and the best show.
Do I need a telescope to see meteors?
No. Meteors flash across large areas of sky, so the naked eye with a wide view is best. Give your eyes 20 minutes to adapt to the dark and avoid looking at your phone.