National Data Buoy Centre (NDBC)

This is a site run by the National Oceanic and Atmospheric Admistration (NOAA), and current data for conditions in the area around each data buoy. It also records conditions for the last 24 hours

• UK Recent Marine Data
• Channel Lightship
• Greenwich Lightship

Met Office

24 Hour weather forecast, inshore and offshore from the Met Office

• Inshore
• High Seas

BBC Weather

No need to say more....

• Weather
• Tides

XC Weather

Seems to provide a reasonably accurate 5 day forecast

• http://www.xcweather.co.uk

WindGURU

Well this one is for Sailors & Wind Surfers. But if you look for the days with no stars against them (i.e. low wind) then they should be good for us.

• http://www.windguru.cz/int/index.php

Magic Seaweed

Surf, swell, webcams and much more.

• http://magicseaweed.com/UK-Ireland-Surf-Forecast/1/

Purbeck Webcam

How about this... Going diving in Swanage, then have a look at what the weather is really like now.

• http://www.purbeck-dc.gov.uk/content/lilin/indexjava.htm