The Wave Period and time between swells is provided by SurferToday.com and NOAA.
Check the peak wave period for the next seven days. Select your surf forecast region:

Hawaii Wave Period Forecast

California Wave Period Forecast

USA East Coast Wave Period Forecast

USA West Coast Wave Period Forecast

Gulf of Mexico Wave Period Forecast

Australia and Indonesia Wave Period Forecast

Atlantic Wave Period Forecast

Puerto Rico Wave Period Forecast

UK and France Wave Period Forecast

Brazil, Mexico and East USA Wave Period Forecast

India and Africa Wave Period Forecast

Alaska, Canada and Russia Wave Period Forecast

 

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