Welcome to the Wave Period service provided by SurferToday.com and NOAA.
Check the primary swell direction and wave period forecast in Alaska, Canada, and Russia for the next seven days:

 

Alaska, Canada and Russia Wave Period Forecast

What is Peak Wave Period Forecast? The NOAA Interpretation

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