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PostPosted: 10 Aug 2014, 15:46 
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Joined: 11 Nov 2012, 23:32
Posts: 627
One of the biggest questions by any newcomer is when is the best time to dive?
Now this has been a hot topic as most members within our club have differing theories/methods that they use to interpret whether an area will be diveable. Regardless of the differing approaches one may take, the main reasons we as divers need to interpret the weather is to make sure the area we are diving is "Safe" to dive and that the "Visibility" we encounter will be good enough to enjoy the activity we are commencing.

In terms of Visibility there are many variables that can play a part - Rain, Wind direction, Previous days wind direction, Swell Height, Previous days swell height, Light levels, Turbidity, Runoff, etc
Without going into every variable a good rule to follow that most divers tend to agree with, is that the best time to dive is usually on or after 2-3days of offshore winds and low swell.

What's Offshore winds vs Onshore winds?
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The simple answer is offshore winds push all the inshore crap(seaweed, sediment, pollution, etc) away from the shore therefore creating better visibility. Whereas onshore winds do the opposite they stir up the bottom and push all the crap closer to shore making the water dirtier.

Swell Height - Is a very important factor. Most divers within our club will only dive certain areas when there is low swell. Anything under 3 feet is usually considered diveable. Yes there will be areas that you can dive that are protected from swell. But we as a club always put Safety first. Regardless of the conditions we encourage any diver to dive with a buddy and if a diving a new location do your research well beforehand and find out what conditions are most favourable to dive that area safely.

What sites are good to use to interpret weather conditions?
This has been a debate for many years. As some favour one site over another. Regardless of which you choose it's always a good idea to compare results from 2-3 sites. That way if there is correlation of results there is a greater chance that the information you are reading is correct.
Without causing any arguments here is a list of "some sites". Which are based from my own experience and from other members on this site.

http://www.willyweather.com.au = good for tide times, sunrise/sunset times & moon phases, daily rainfall.
http://www.seabreeze.com.au = usually good for wind direction
http://www.windguru.cz/int/ = another good one for wind direction
http://www.bom.gov.au = wind direction, rain forecast, warnings
http://www.swellnet.com = swell height, surf cams
http://magicseaweed.com/ = wind direction, swell height and direction

Here are some other sites but haven't used them
http://www.buoyweather.com/
http://www.baywind.com.au
http://www.baywx.com.au

Some of the coastal web cams are also good to look at.

Good luck and safe diving!

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PostPosted: 12 Aug 2014, 13:44 
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Joined: 03 Aug 2006, 09:55
Posts: 622
Location: Melbourne
Hi Jeoff,
If I may I might expand on your very useful post by briefly mentioning a simple consideration on swell period, as this might impact on ease of access or exit from rocky shore dives.
Other divers with more experience in reading this parameter can add further to the below.

Most surf reports show swell height, direction and swell period.
Whilst swell height and direction can be read quite intuitively, perhaps swell period needs to be commented on to better understand a basic swell parameter when diving close to shore.
Please note the brief explanation below as provided by Willyweather.

What is Swell Period?
Swell period tells us the approximate distance between swell waves. It is defined as the amount of time it takes for two consecutive wave crests to pass a stationary point.
How can Swell Period be used?
Swell period can be used to help determine onshore wave heights. A longer period results in a more powerful wave [close to shore], forming a higher face than swell of a similar height but with a shorter period. The exact height and quality of the waves will also depend on the contour of the seabed, wind speed and direction.

...In essence, swell of similar height but with different swell periods could have considerable impact on how easily it is to access or exit one spot, as the swell with greater period will carry a greater push / draw.

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PostPosted: 13 Aug 2014, 19:28 
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Joined: 16 May 2011, 20:54
Posts: 353
Have a Bouyweather membership and it has become my number 1 for predicting conditions. Has amazingly (on a few occasions) been pretty close even 5 days out. Agree you need to compare a few sites to get the full picture. Nice!


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