- The 2027 Perseids peak on the night of 12 Aug–13 Aug; active 17 Jul – 24 Aug.
- Up to 100 meteors an hour in a perfect sky; on the peak night in London about 52 from a dark site, about 16 from town.
- The Moon is 85% lit but below the horizon at the best hour: the sky is dark.
- The radiant is in Perseus, highest around 04:10.
- Source: 109P/Swift–Tuttle; speed 59 km/s.
When to look in 2027
The Perseids are active from 17 Jul to 24 Aug. The curve shows activity rising and falling, the dots under it how much of the Moon is lit each night.
Night by night
For each night the best hour is computed: the radiant high, the sky dark, the Moon in the way least. A dark site means out of town where the faintest stars show; town means a bright suburban sky.
| Night | ZHR | Moon | Best | Dark site | Town |
|---|---|---|---|---|---|
| Fri 6 Aug | 8 | 28 % | 03:40 | 4 | 1 |
| Sat 7 Aug | 12 | 39 % | 03:40 | 7 | 2 |
| Sun 8 Aug | 19 | 49 % | 04:00 | 11 | 3 |
| Mon 9 Aug | 29 | 59 % | 04:00 | 17 | 5 |
| Tue 10 Aug | 45 | 69 % | 04:00 | 27 | 8 |
| Wed 11 Aug | 70 | 78 % | 04:00 | 43 | 13 |
| Thu 12 AugPeakmost meteors | 85 | 85 % | 04:00 | 52 | 16 |
| Fri 13 Aug | 35 | 91 % | 04:00 | 22 | 7 |
| Sat 14 Aug | 14 | 96 % | 04:00 | 9 | 3 |
| Sun 15 Aug | 6 | 99 % | 04:00 | 2 | <1 |
| Mon 16 Aug | 2 | 100 % | 04:00 | <1 | <1 |
| Tue 17 Aug | 1 | 99 % | 04:20 | <1 | <1 |
| Wed 18 Aug | 0 | 97 % | 04:20 | <1 | <1 |
Where to look
The meteors fly out of the radiant in Perseus. In London it stays above the horizon all night and is highest, 67°, around 04:10.
You do not have to look at the radiant itself: meteors appear all over the sky, and the longest ones 40–60° away from it. Lie back, take in as much sky as you can and stay with it for 20–30 minutes so your eyes adapt.
Where they come from
The Perseids are dust from Comet 109P/Swift–Tuttle. Its nucleus is about 26 km across and it orbits the Sun every 133 years: it was last near the Sun in 1992 and will return in 2126. Every August the Earth crosses its broad dust stream.
History
The Perseids have been watched for at least 2,000 years. In Europe they are called the Tears of St Lawrence, as the peak falls near his feast on 10 August. In 1866 the Italian astronomer Giovanni Schiaparelli showed that the Perseids travel on the same orbit as Comet Swift–Tuttle: the first proof that meteor showers come from comets. In 2016 rates were about twice the usual.
What they look like and how to watch
Perseids are fast (59 km/s) and often bright, with many fireballs and glowing trains. From northern Europe the radiant in Perseus never sets, so meteors appear from the evening, with the most before dawn when the radiant is highest. Warm August nights make this the easiest shower for a first look.
How many meteors you will really see
The ZHR (100) is how many meteors an observer would see in an hour in a perfectly dark sky with the radiant straight overhead. The real count is always lower: the lower the radiant, the more meteors stay below the horizon, and every step of sky brightness hides the faintest ones.
This page uses the International Meteor Organization formula: hourly rate = ZHR × sine of the radiant altitude ÷ r^(6.5 − limiting magnitude). For this shower r = 2.2. A dark site is taken as showing stars to magnitude 6.0, a town to 4.5; moonlight takes off up to 1.8 magnitudes.
How to photograph a meteor
You need a camera with manual mode and a tripod. Wide-angle lens (14–24 mm), aperture wide open (f/1.8–f/2.8), ISO 1600–3200, exposures of 15–25 seconds. Focus manually on a bright star and tape the ring.
Shoot continuously with an intervalometer or remote, frame after frame for an hour or more. Meteors are random, so patience wins: one or two an hour is a normal catch. Aim 40–60° from the radiant, above the glow of the horizon.
Dates in the coming years
| Year | Peak | Moon |
|---|---|---|
| 2028 | Friday · 11 August 2028 | 63 % |
| 2029 | Saturday · 11 August 2029 | 8 % |
| 2030 | Monday · 12 August 2030 | 99 % |
| 2031 | Tuesday · 12 August 2031 | 23 % |
| 2032 | Wednesday · 11 August 2032 | 29 % |
| 2033 | Thursday · 11 August 2033 | 96 % |
Other meteor showers
Questions people ask
When are the Perseids in 2027?
The peak is on the night of 12 Aug–13 Aug. The shower is active from 17 Jul to 24 Aug, so meteors show for several nights before and after.
What time is best?
In London on the peak night, around 04:00, when the radiant is 65° up and the Moon interferes least.
How many meteors will I see?
A ZHR of 100 is the perfect-sky figure. In London on the peak night expect about 52 an hour from a dark site and about 16 from town.
Which way should I look?
Meteors come from the direction of Perseus but appear all over the sky. Look 40–60° away from the radiant, at the darkest part of the sky.
What causes the Perseids?
Dust left by 109P/Swift–Tuttle. The Earth crosses the stream at the same time every year, and the grains burn up in the atmosphere at 59 km/s.
Will the Moon get in the way?
The Moon is 85% lit but below the horizon at the best hour: the sky is dark.
- International Meteor Organization, Meteor Shower Calendar: activity periods, solar longitudes of the peaks, ZHR, population index.
- IMO Visual Observing Handbook: the hourly rate formula (ZHR, radiant altitude, limiting magnitude).
- Astronomy Engine (Don Cross): positions of the Sun, the Moon and the radiant.
- JPL Small-Body Database: comet and asteroid orbits.
The peak date is computed from the Sun's ecliptic longitude. The activity curve is the IMO model ZHR(λ) = ZHRmax · 10^(−B·|λ − λmax|). For each night the radiant altitude and the Sun and Moon are computed every 20 minutes; the hour with the highest expected count is shown.