The semi-recent advent of strategically placed surface buoys have allowed everyone to have complete up-to-the-minute sea height, direction, interval, as well as barometric pressure, and wind speed calculation, which are instrumental in predicting future swell size and surface conditions up to approximately 14 days before reaching any given coastline around the world.
These are a handful of my favorite advanced internet resources used to predict up-coming swells and weather conditions in order of appearance. Order may vary slightly depending on region, being that some forecasters intel and attention to area may be biased.
NOAA Wave Action Model = Raw government data – foundation of most forecasts. Click height or period then scroll down for animation and hit display.
National Data Buoy Center NDBC.NOAA.gov = Real time readings directly from the buoys. Great for morning of the swell predictions to see exactly when the swell will hit and what time of day will be biggest.
BuoyWeather.com = Virtual buoy data for wind and swell height/period up to 6 days out. Membership needed in order to see prediction from day 3 to 6.
Surfline.com = Foolproof forecast information up to 14 days out. Complete with text, live cameras, charts, storm animation, and all of the latest and most advanced actual and future prediction information for every region of the world. Membership needed to see extended forecast.
WindGuru.com = Accurate height/period, and most importantly wind speed/direction information. No membership needed and found it works best in South Pacific.
StormSurf.com = Swell height and period information combined into animated charts. Wind animation also available. No membership needed.
SurfNewsNetwork.com = Great site for Hawaii swell and weather information.
MagicSeaweed.com = Daily cameras and more importantly animated swell height/period combination that I’ve found works especially well for South America. No membership needed.
Summary – There is more information out there than can be processed. I recommend finding a site or two whose configuration you like and stick with it. You’ll eventually be able to have a great idea of how the waves will be at any given spot after reading reports from the same sites and then going to the beach and checking the surf over an extended period of time.
Personal – I usually just look at NOAA WAM (first link) raw government data to see where storms are forming, then Buoy Weather and Surfline to back up my personal predictions and get wind data. If the swell looks promising or I’m on the fence about going to a few different spots, I’ll read data from the rest of the links. If I need extremely accurate information the night before or morning of the swell, I’ll look at the real time buoy data from NDBC (2nd link).
Most of these sites have apps for smart phones so you can keep up with the latest intel.