It's shaping up to be a stellar year for fall colours, thanks to the weather, and an expert says the best is yet to come.

Fall colours foliage good year Gatineau Hills Oct 2014

It's been a good year for colourful fall foliage, and an expert says the brightest leaves haven't yet arrived. (CBC)

Thousands of spectators are filling Gatineau Park to take in the sensational fall foliage. The science behind that view involves the right mix of temperature and sunlight.

"The two key factors that lead to really vibrant red colours in the fall are low temperatures and high light," says Jeffery Saarela, a research scientist at the Canadian Museum of Nature.

Saarela says the best fall views haven't yet arrived. If the weather co-operates, colours should peak with more vibrant reds in the next couple of weeks.

To see more, check out the video in the player above.