The little bits of interplanetary grit making up the Perseid meteoroid stream orbit the Sun with a period of about 130 years, like their object of origin, Comet 109P/Swift-Tuttle. The richest part of the stream is strung out near the comet itself, which last dipped through the inner solar system in 1992. So the shower's annual sky show has waned of late — gone are the great Perseid meteor displays of the early 1990s.
This year's standard Perseid peak is predicted to come around 18h Universal Time (2 p.m. Eastern Daylight Time) on August 12th. That's good timing for the Far East, but for North America it splits the difference between the nights of August 11-12 and 12-13. Flip a coin — or watch the evening weather forecast — to decide which night to watch for them. The shower is also active to a lesser degree for many days beforehand and several days afterward.
The waning Moon is nearly at last quarter those two nights. It rises an hour or two after dark and will brighten the sky somewhat during the best Perseid-activity hours, from 11 p.m. until dawn. Nevertheless, this is a pretty reliable shower, and some Perseids should be there for the catching.
Moreover, meteor specialists Esko Lyytinen and Mikhail Maslov suggest we may encounter a ribbon of very old debris (ejected by the comet in 1610) on the morning of August 12th near 9h UT (4 a.m. CDT; 2 a.m. PDT). This could up the count for an hour or so. Both researchers also think that Earth's proximity to the stream's core might produce an additional surge four hours earlier, around 5h UT (1 a.m. EDT).
You may also see occasional meteors from two lesser showers that are also active: the Delta Aquarids and Kappa Cygnids. These move noticeably slower than Perseids, and they travel in different directions as if originating from their respective constellations.
Meteor watching is great "eyeball astronomy." Find a spot with an open view of the sky, wrap up warmly in winter clothes or a sleeping bag, and use mosquito repellent where you're not wrapped. Lie back in a lounge chair and watch whatever part of your sky is darkest. Be patient. You may see a meteor zipping into the upper atmosphere every few minutes on average.
Click here for Sky & Telescope's guide to the year's major meteor showers.