The primary swell direction and wave period forecast are provided by SurferToday.com and NOAA.
Check the time in seconds between waves for the next seven days. Select your surf forecast region:

 

Hawaii

California

USA East Coast

USA West Coast

Gulf of Mexico

Australia & Indonesia

Atlantic

Puerto Rico

UK & France

Brazil, Mexico & Southeast USA

India & Africa

Alaska, Canada & Russia

 

The technical notice made by NOAA:

The peak period identifies either the period (the time between waves) associated with the locally generated wind sea (in cases with strong local winds) or the dominant wave system (swell) that is generated elsewhere.

Note that this peak period field shows discontinuities.

These discontinuities can loosely be interpreted as swell fronts, although, in reality many swell systems overlap at most locations and times.

NOAA - National Oceanic and Atmospheric Administration