On Wed, 22 Nov 2006 02:20:25 GMT, in message
JtO8h.3548$_x3.1618@trndny02
"NE Sailboat" wrote:

when I see a marine weather report, the wind direction is given. for
example: wind from the southwest at 10-15 knots.

is the wind direction based on the true compass direction or magnetic?

So,, wind from the southwest = wind from 225* true

And if along the coast of Maine this would mean = wind from 242* magnetic

I don't think any of the forecasters actually intend you to take a
bearing from their forecast. When I feel confident I interpret 10-15
from the southwest to mean 5 -20 from a direction somewhere between
south and west, so variation is moot.

SW is a 45 degree octant.

Ryk