11/28/2013 08:56 EST | Updated 01/28/2014 05:59 EST

What is a temperature inversion?

On long stretches of lingering fog or days when the mountains are warmer and sunnier than down at sea level, a temperature inversion is often to blame.

It is a common occurrence here in Vancouver, and is a term many Vancouverites may know well. But what exactly is it?

Johanna Wagstaffe answers that question in this week's Science Smart.

If you have a science question you'd like answered, send Johanna a tweet (@Jwagstaffe) or an email: