Tides change everything.....in some places.
Last week I was talking to one of our esteemed readers and he mentioned to be getting great waves lately. I, on the other
hand, told him that I'd been missing on all the action mostly because I was surfing during the wrong tides.
Tides change everything where I surf, Portugal, but it's not like that around the world. This week I had somewhat of a
revelation. You may have already figured this out depending on where you live or traveled to and how much you put into
Tides in Portugal function like clockwork. Roughly 6 hours in and six hours out. You know that each day the tide shifts
approximately 1 hour forward. It's not exact but as a general rule it holds pretty well. To my surprise, tides in other
parts of the world work very differently.
When analysing tides, there's 2 things to look
- tide range - the difference in meters between high and low tide
- tide length - how long it takes to go from high to low tide and conversely
(these are my definitions not scientific)
I knew that the tide range, measured in meters, was different around the world but I didn't know that the length could
be different. To me, anywhere around the world, the tide would fill for 6 hours and go out for 6 hours (give or take).
Oh boy, was I mistaken. I've been to places like Australia, Nicaragua, Indonesia and others. If I knew all this at some point,
I certainly forgot. Let's dive in.
You can see that it's very regular. It changes during the month and depending on the moon cycle the different in
meters between low tide and high tide can be bigger or smaller. On the 12th of April there's a low tide of 0.73m and high tide of 3.70m.
Around 3meters difference between tides. On a low variance tide cycle like the 6th of April the difference
is around 1.5m.
Heading over to Bali and the revelation begins. I've been to Bali a few times but didn't notice how different the tides
were. From the 9h till the 16th April it seems to follow a pattern similar to Portugal.
However, on the 5th of April for example, we have a low tide 0.83m at 10:21pm. Going into the next day we have a high
tide of 1.41m at 4:53am. After only 3 hours to reach a low tide of 1.21m at 9:13am. From there we have 7 hours for a high tide
at 4:28pm. Fascinating. Also note that tide range changes a lot.
|Denpasar, Bali, Indonesia
San Clement, home of Trestles, also is very different from what I was expecting. First the
tide range is a lot smaller. The biggest tide variance is around 1.5m on the 8th April which is half of a big cycle in Portugal. On the 17th it seems like we
skip a cycle. From 7:21am until the end of the day tide is always rising. But we get an intermediate high and low tide.There's a high
tide of 0.78m and low tide after only 2.5 hours of 0.75m. That's 30cm difference between high and low tide.
|San Clemente, California, USA
I'll leave you with 3 more charts for you to analyse. Gold Coast, home of Snapper Rocks an Kirra in Australia, Cape Town
in South Africa as an approximation to Jeffreys Bay and Haleiwa, Hawaii.
|Gold Coast, Australia
|Cape Town, South Africa
If you want to explore further check tide-forecast.