why is late july and the begining of august the best time to see falling stars?

Answer 1

The real reason is that the evenings and nights are still comfortable enough for people to stay up and watch the meteor showers. Also, they are well publicized at that time of year.

A dozen times a year, the Earth goes through regions occupied by greater concentrations of dust and pebbles strewn along the orbit of comets. The comet itself may be far away at the other end of its orbit, but if the comet has been going around long enough, there will be "stuff" all along (and around) its orbit.

When we go through these regions of "more stuff", we get more shooting stars than usual.

Here are some popular showers:

Perseids, Aug 13 (+/- 2 days) 90 per hour
Geminids, Dec. 14 (+/- 1 day) 120 per hour
nu-Aquarids, May 5 (+/- 5 days) 60 per hour
Leonids, Nov. 18 (+/-1 day) 15 per hour

The duration (shown as +/-) is the number of days on either side where we can expect at least 50% of the maximum expected rate.

For example, the Perseids actually last of weeks. However, their rate is very low until about August 11 when it finally reaches above 40 per hour (in a dark site, with no Moon and a clear sky). The "good viewing" window lasts until August 15 or 16.

The Perseids really last from late July to late August, but the rate is poor until you get within two days of the maximum.

The Geminids have a better maximum rate but the good viewing window is much shorter, the meteors are much slower, therefore not as bright (30 km/s instead of 60 km/s for the Perseids) and December 14 is usually much colder (in the Northern hemisphere) than August 13.

Answer 2

You can see shooting stars (meteors) any night the sky is clear.
But the most visible meteor shower in most years are the Perseids, which peak on August 12th of each year at over 1 meteor a minute.
There are also several large meteor showers at other times of the year:
- Quadrantids in January
- Lyrids in April
- Eta Aquarids in May
- Areitids in June
- South Delta Aquarids in July/August
- Perseids in August
- Orionids in October
- Geminids in December

The reason people see more meteors in July and August is that the weather is warm and people are out at night longer. Add to that the fact many people vacation out of big cities where the night skies are darker.