There is a constant relationships between the period of a wave and the speed at which it travels. A longer period swell means the waves are traveling faster and have more energy. When waves have more energy, it means bigger more powerful waves at the beach. For this reason, a 5ft. swell with a 13 second period will almost always be better than an 8ft. swell with a 9 second period. Usually a swell period of 6 seconds or less indicates weaker wind swell and generally less "focused" energy. When the period is greater than 12 seconds, this typically indicates more powerful "ground" swell, which will generate bigger more powerful surf.
More Tips

Wave Height: 2 ft
Swell Period: 9 secs
Swell Direction: ESE
Wind Speed: 7 mph
Wind Direction: Onshore (E)