Hello there. When they say the tide is x metres, do they mean the size of beach is x metres or the depth of water?

Pete

Depth of water on tide table.

So if it said it was 7m, there would be less beach than 0m?

0 is the average of all the low tides of the year. So 0m has more beach than 7m and every once in a while you get a negative tide and thats the most beach you'll get.

freeflyfrog,

what site are you looking at for your wind/tides??
if you buggy at sf beach check this site its so much easyer to understand,
theres also a tide link in the top corner, click it and it shows tides throughout the day on a very easy to read scale.... and also has current photos of weather at the funston location.... (this site relates to fort funston but its only a few miles down the road to the beach, pretty accurate)

http://funston.appweb.org/webcam.htm

i use www.iwindsurf.com it has funston on it and a whole lot more. I use streaklines too to give me a "birdseye view" of what the wind is like. I've been staring at it for days now waiting for some wind! I just got some new kites and I'm dying to go try them out!

7m? Holy crap that's a huge tide. Yeah I know, some places get up to 15m tidal swings - crazy!

The 0m tide should represent actual sea level, if the moon and the sun weren't affecting the tide in that area. It is not the tidal average, since most habited areas experience averages greater than zero. Zero tide happens regularly of course, but its because the forces of the sun/moon equal out in that area at that time. Negative tides aren't that uncommon either. They'll always accompany a spring tide condition (this has nothing to do with the season of spring). In a spring tide, the relationship of the bodies is either sun-earth-moon (full moon) or sun-moon-earth (new moon). The pull stretches out the earth (land too actually, but to a smaller degree) and gives extremely high and low tides on either side of the earth.

Additionally, there's the semi-rare Proxigean Spring tide, which occurs when the moon is particularly close to the earth during its orbit and in a new moon phase. These are accompanied by ridiculously high and low tides.

To answer your question, lower # equals more beach.

So how many minus tides do we get in a year??
Does it change drasticlly from year to year??
thx

It really depends on the year. I'm sure there's some astro-physicist out there that has calculated out all the tides for the next 600 years and wrote a program for it. Just count on having your extreme high and low tides around the full and new moons. Go into any surf shop in Nov-Jan and pick up a tide calendar for the following year. Here's a list of the Proxigean tides until 2020:

LINK

The next really nasty one won't be for 10 years. Doh!

New moon = low tide
Full moon = high tide?

It switches doesn't it?