Frost possible overnight in central and southern Alberta

This week will begin with mild and clear conditions in central and southern Alberta. In Calgary, the daytime high will reach 21 C on Monday with highs in the low 20s for much of southern Alberta. There will be very little cloud cover and only a light wind throughout the day and overnight, and (especially) in rural communities frost is possible overnight. Nocturnal cloud cover can serve to trap heat in during cooler overnight periods, and wind can help to mix the air in the lowest levels of the a