Several flights were delayed, cancelled or diverted due to heavy fog at the Calgary airport Tuesday evening, according to an airport spokesperson.

However, the airport said as of 10:20 p.m. unless weather conditions changed, the airport was likely through the worst of the impact.

"As fog continues to linger across Calgary and Western Canada we do encourage guests to check the status of their flights prior to heading to the airport," a WestJet spokesperson said in an emailed statement.

Earlier in the day, Environment Canada issued a fog advisory for Calgary and parts of southern and central Alberta warning of near-zero visibility.

The fog was expected to thicken overnight, the agency said around 3:30 p.m. Tuesday.

Visibility was expected to improve late Wednesday morning.

The agency suggested drivers slow down, watch for tail lights and be prepared to stop if visibility is low.

Advisories were also issued for the following areas:

Rocky View County.

Siksiksa First Nation.

Vulcan County.

Wheatland County.

Drumheller.

Red Deer.

Ponoka.

Stettler.

A full, up-to-date list of weather advisories is available on Environment Canada's website.