The Sky Zone

When you want to know what the weather is like, where do you look? At the sky of course!

Looking up at the sky can answer a lot of questions, from "what time is it?" to "do I need my coat?" and plenty of others

But did you know we can also use the sky to tell us about the levels of pollution in the atmosphere? Read on to find out more.

Sky Colour


Deep Blue

A very clean sky. A deep blue sky can occur when a cold front brings in clean, unpolluted air from the north. A deep blue sky can also occur when clean air from over the ocean is pushed over the land.


Medium Blue

A medium blue sky suggests that there is a lot of water vapour in the air, but it can also be causes by coal burning power plants.


Pale Blue

A pale blue or milky sky can suggest that there is a lot of air pollution, possibly from coal burning power plants, or it may have accumulated on a particularly still day.



Suggests the possibility of considerable air pollution in the form of sulfur from coal-burning power plants or certain chemical plants. In some areas this condition occurs mainly in summer when the air is still and pollution accumulates. There are also natural sources of sulfur dioxide, including volcanoes and ocean plankton. Large portions of the island of Hawaii have often been blanketed by a thick layer of hazy sulfur dioxide from the Kilauea Volcano.