I have found that
www.weatherunderground.com is very general.....and sometimes wayyyy off. If you know anything about the weather and have been fishing long enough, you can read the synopsis at the top of the page and it tells you all you need to know about the forecast. However, if you are not familiar with the weather patterns in relation to fishing go to the map at the bottom of the page, and go to the wave heights link....once there click animate map....and this is much easier to understand than the text that they give you, the darker the purple/pink the calmer it will be, just go to the time frame you are looking to fish and check it out, and it is accurate enough to go offshore on...I fish a lot and I trust it quite a bit. One other thing,
www.bouyweather.com site is usually right on with the wind speeds but the wave heights are usually off from my experience.