Calgarians hopefully enjoyed the sunshine this weekend because a big, chilly weather change is forecast for the city Monday night that may bring September snow to the area.

CBC weather specialist Vickie Chase says a polar front system will move in from the north over the weekend, and will start to affect northern Alberta on Sunday.

Calgarians won't see the impact until Monday. Rain is in the forecast during the day, which is expected to turn into snow in the afternoon with the potential for 5 cm of snowfall and temperatures hovering just above zero.

"You won't need me to tell you that it's arrived because it is going to drastically change things for us," said Chase.

Environment Canada says Tuesday's forecast for Calgary is cloudy with a 60 per cent chance of flurries or rain showers, including a low of zero and high of 4 C.

Chase said the good news is the snow is expected to melt right away.

The upper elevations of the Rocky Mountains have already seen some snow this week.