Weather

This section contains local weather summaries. To the left, you’ll find summary pages with focus on the data we need to know as divers.

If you’re new to reading weather and trying to work out whether it’s a good time to dive, a little guidance.

Slack Tides #

Slack tides are the point where the water movement is minimal. This is typically an hour either side of the high or low tide. For some sites, when you dive on the tide is irrelevant, for others it’s a critical safety concern.

The depth shows the depth above lowest astronomical tide, which is the lowest depth we could expect due to purely astronomical effects. As you gain familiarity with local areas, you’ll get a feel for how your favourite dive sites look and feel at different depths. This often impacts the types of sea life you will see and, especially for rocky entries, can also impact the entry and exit.

The delta shows how much difference there is between the previous tide and this one. The larger this number, the more water movement you can expect. Local knowledge is important to understand how this will impact your dive.

Precis #

This is the meteorological precis, which is a short summary of the overall weather. It is focussed on how sunny, cloudy, rainy or windy the weather will be.

Temp #

This is the surface temperature. The water is usually going to be colder.

Rain #

While rain doesn’t impact us while diving, it can make entries and exits more challenging.

The range is an expected amount of rain and the probability tells us how likely that will be.

Swell #

This is the wave height and the time between waves.

Direction tells us where waves are coming from. That is, if you face in this direction, the waves will be coming at you.

Height is the height above the calm surface we can expect to see. This gives us an indication of how large the waves will be. As waves will also drop below the calm level, the perceived wave will be a bit larger.

Period tells us the time between waves. The larger the period, the longer it will be between them. Typically, above 10 seconds is fairly flat.

UV #

This is the ultraviolet index. This is here to give an idea of how careful you need to be about sun protection when preparing to dive or between dives.

Wind #

The wind has a big impact on future conditions as well as how quickly you’ll get cold after diving. As with swell, direction is where the wind is coming from.

The swell is also impacted by wind. In the southern hemisphere, the swell will be offset to the left of the prevailing wind direction. Persistent winds from a single direction will eventually cause the swell to be approximately 45º to the left of the wind direction. This means that an easterly wind will cause a north easterly swell. For those interested in learning more, this effect is called the Ekmon Transport.

You may hear some people still using knots for wind speed. A decent approximation is to double knots to get km/h.