Wave and swell forecasts can be obtained from most of the same places as wind/weather forecasts. It’s sometimes also worth consulting information intended for surfers - e.g. http://magicseaweed.com. Wave forecasts will normally include:
- Wave height - can our group cope with the forecast waves? What effect will they have when they strike the coast? Waves of 1 meter will feel serious to an inexperienced group. This is about the height when group members will sometimes disappear in the troughs.
- Wave period - long period swell (e.g. 10 seconds or greater) is easier to paddle in than short period chop. However, long period swell implies a bigger wave for a given height, so the effect of the wave breaking will be more powerful.
- Wave direction - suggests where we can find shelter. Waves will tend to diffract around headlands, so shelter may be imperfect depending on the shape of the coastline. This video (15 mins) gives a good illustration of this sheltering effect. If you watch it, I suggest keeping a map of the area to hand so that you can easily understand how the locations mentions relate to each other.