Sunset Photography Tips
Photographing sunsets can be very rewarding, especially if there are intense colours in the sky. Below is the method I use to predict if there is chance the sunset will be worthwhile.
Clouds, Clouds and Clouds...
The biggest contributor to a dramatic sunset are the clouds. But not all clouds are good.
Essentially there are 3 levels of clouds that we observe: Low, medium and high level. We desire high level clouds, are worried about medium clouds and do not want low clouds at all. Here is why.
As the sun gets lower in the sky it's light starts to reflect on the bottom of the high clouds, often producing those great colours we see (reds, oranges and yellows). If the high clouds extend well beyond your visible horizion you may get some colour but more muted and diffused rather than intense and dramatic.
Medium clouds can get in the way of this, though in some cases may enhance the scene. This is why medium clouds are a 50/50. Lots of thick continuous medium clouds probably won't be good but patchy medium clouds may produce those 'rays from heaven' in some cases.
Low clouds just block everything if they are in the area so they are not going to be our friends.
How To Work Out What Clouds Are Where
Fortunately this is fairly straight forward. A website called Skippysky provides good information on cloud cover. It is aimed at astronomers and is a free service, Please consider making a donation if you find it useful and/or it helps you commercially. It is run by Andrew Cool based in Adelaide, South Australia.
Simply select your region and you are presented with a lot of options. Choose your location on the area selected (Adelaide, Australia in my case)
Across the top of the page are options to view the cloud levels as well as move forward in time (to +120 hours) to see predictions of future cloud cover. Below are examples of low, medium and high cloud cover from the same point in time as an example of what you will see. Although these are around 11:30 am CST (+10;30 UTC) if we imaging this is what we were expecting at sunset then I would probably consider it less likely a nice sunset given the heavy amount of middle cloud. I would, however, try and see how fast the middle clouds are moving as there is a relatively thin band of middle clouds, with lots of high level clouds. Low clouds in the image below are good (not many).
In conjunction with SkippySky your local weather forecasting service may assist with information on other aspects of the weather, such as rain or lightning, which may add or subtract from your desire to venture out. Of course, all of these are predictions and anything is possible. These techniques merely help is assessing the likelihood of a good sunset. Your mileage may vary !