Perseids 2027: the peak comes in daylight; watch on the night of 12–13 August

The 2027 Perseids reach their peak on 13 August, between 08:00 and 10:00 UT, according to the calendar of the International Meteor Organization (IMO). On the Spanish mainland that is 10:00 to 12:00, in broad daylight, so in Spain the night to set aside is the night of 12–13 August, ten days after the eclipse. The shower is active from 17 July to 24 August, and on those nights the Moon will be halfway between first quarter and full: there will be little moonless sky.

The dates, according to the IMO

The ZHR is a reference figure: the number of shower meteors one person could count in an hour with a perfect sky and the radiant (the point they all seem to come from) directly overhead. With the radiant lower or a poorer sky, fewer are seen, the IMO itself explains, because many of the faint ones are lost.

For 2027 the IMO also gives two predictions. Maslov’s: the part of the particle stream the Earth crosses in 2027 is somewhat closer to our orbit because of Jupiter’s pull, and that could raise activity by 10 to 20% (a ZHR of 110 to 120). And the encounters with dust trails in Jenniskens’s table, one of which falls right in the Spanish night: the one at 23:46 UT on the 12th, 01:46 on the 13th in mainland Spanish time, which that table gives a ZHR of 280 (the other, a few hours earlier, would be weak). Maslov adds that around 02:00 UT on the 13th, 04:00 on the mainland, a fragment of an old trail could add a little activity. To check these predictions, the IMO asks observers to log their counts in intervals of half an hour or less.

The Moon on those days

The eclipse of 2 August falls at new moon, like every solar eclipse: NASA’s table of phases marks that day with a T, for total eclipse. Then come first quarter on 9 August, full moon on 17 August and last quarter on 25 August. The full moon of the 17th also brings a penumbral lunar eclipse that won’t be visible from Spain, as we explain in the eclipses of 2027.

On the nights of the 12th and the 13th, says the IMO, the Moon is halfway between first quarter and full, so the moonless stretch around the peak will be short. According to the IMO again, a full moon cuts the number of meteors seen roughly tenfold. The Moon on those nights isn’t full yet, and the Instituto de Astrofísica de Canarias (IAC), the astrophysics institute in Spain’s Canary Islands, has a tip for years with moonlight: look towards the part of the sky farthest from the Moon while it is above the horizon.

As for timing, from northern mid-latitudes such as Spain’s, the radiant is already reasonably high from 22:00 or 23:00 local time, according to the IMO, and NASA notes that the Perseids are best seen in the hours before dawn.

Where to watch them

The IAC recommends a dark, clear sky, away from city lights and from obstacles such as buildings, trees or mountains. You don’t need to go very high, and a beach or a stretch of coast with little light pollution can work. Your eyes need between 10 and 20 minutes to adjust to the dark, so during that time, no phone and no torches. And it’s better lying down: a reclining chair, a blanket or a towel.

If you feel like counting, your counts are useful: for the IMO, naked-eye counts are still an important part of the data for many showers. And if you like measuring things, experiments during the eclipse has four for the morning of 2 August.

From the eclipse to the Perseids

During totality on 2 August, what you will see next to the Sun are planets: Venus 2.9° from the Sun, directly above it, Mercury at 10.1° and Jupiter lower down, 1.3° from Regulus. We cover them in which planets will be visible (in Spanish), and what happens in those minutes in what is totality (in Spanish). If you go south to see the eclipse and stay on for August, the night of 12–13 August will find you there. The time and length of your eclipse are in will I see it?, and why there isn’t an eclipse at every new moon, in our learn section.

Sources: 2027 Meteor Shower Calendar — International Meteor Organization (activity, peak, ZHR, speed, comet, Maslov’s calculation, Jenniskens’s trails, the Moon on the nights of the 12th and 13th, the radiant’s altitude, visual counts and half-hour intervals); Major Showers Observations — IMO (what the ZHR is, a low radiant and the effect of the full moon); Phases of the Moon: 2001 to 2100 — NASA (the phases in August 2027 and the eclipses of the 2nd and the 17th); Perseids — NASA Science (the hours before dawn); Perseidas 2025: cómo ver la lluvia de estrellas (a pesar de la Luna) — IAC (in Spanish: where and how to watch, and what to do about the Moon); eclipseando data (the planets during totality, skyfield + DE440s engine).