What makes a rainbow?

An explanation of atmospheric optical phenomena

Here at MetService, people often send us photos of interesting clouds, unusual weather, and also atmospheric optical phenomena. Atmospheric optics is the branch of physics which describes how light interacts with the Earth’s atmosphere, to create a wide range of visual spectacles. Things such as rainbows, ice haloes, and crepuscular rays all come under atmospheric optics, along with many others. These can be observed all around New Zealand under the right conditions.

Wellington Rainbow

With  a superb view over Wellington and the harbour from the MetService building in Kelburn, we're often (and quite appropriately)  treated to some fantastic weather related vistas. Here's a little sample, snapped on Monday 26 October 2009 as a few light showers passed over the city in a northerly flow late afternoon.