Radiant of a meteor shower. Generally not a point but a small area, here intentionally exaggerated in size. Solid arrows represent plotted paths of observed meteors. By extending these paths backwards, observer can determine the radiant.
In the course of each year, the earth passes through a number of particle-swarms of varying densities. Some of the resulting meteor showers, like the Leonids and Giacobinids, are very feeble in most years, but sometimes produce spectacular displays.
The more important recognized meteor showers are:
| NAME OF SHOWER | DATE OF MAXIMUM |
| Quadrantids | January 1-3 |
| Lyrids | April 21 |
| Eta-Aquarids | May 4-6 |
| Perseids | August 10-14 |
| Giacobinids (Nu-Draconids) | October 9 |
| Orionids | October 20-23 |
| Leonids | November 16-17 |
| Geminids | December 12-13 |
Certain daytime streams are also known to be active during June and July. These daytime showers are, of course, invisible in the glare of sunlight, but they can be picked up by radar devices like those used in World War II to spot enemy airplanes.
Some meteor showers have been splendid enough to make a place for themselves in the historical record. Examples are the Leonid returns of 1833 and 1866, and the Giacobinid showers of 1933 and 1946. During these displays, meteors fell in a veritable fiery snowstorm, several hundred meteors sometimes appearing within a minute.
Not every annual return of a meteor shower is spectacular, however, since conditions may not be favorable each year for a brilliant display. After all, both parties to a traffic collision at an intersection must try to pass through the intersection at the same time. Our earth, like a well-managed train, always goes through the intersection on schedule, but the particles responsible for meteor showers are much more erratic. They may be early or late—or they may not show up at all. Of the meteor showers seen annually, the Perseids are the most dependable. The Leonids put on their best shows at intervals of 33 years (1799-1800, 1832-33, 1866, etc.). The Giacobinids at intervals of 6½ years (1933, strong; 1939-40, poor; 1946, magnificent).
If you plan to observe a meteor shower, here are some suggestions. You will need:
Acquaintance with the stars, both faint and bright, in the region containing the radiant of the shower.
Comfortable reclining lawn-chair.
Warm clothing (including blankets) for winter showers or summer ones at high elevations.
A patient family that will not only approve of your observing but will help you get up to watch after midnight, when most showers are at their best.
A corner of your back yard (or sun roof) where you can shade your eyes from street lights and other illumination.
Timepiece, preferably with radiant dial.