In my limited experiences with ocean kayaking, I've noticed that windspeed is only part of the equation and that there are other factors that are surprisingly important (well, surprising to me, anyway). Like the direction of the current relative to wind direction --- if the wind and currents are going in opposite directions, the swell/chop seems to increase in amplitude and decrease in wavelength, making for much nastier conditions but if the wind is blowing the same way the current is going it has a marked calming effect.
The more information you have, and the more accurate it is, the better.
Because I don't have a drysuit yet and am still learning, and go solo a lot, anything over Beaufort scale 4 conditions makes me think twice.