Mondego River
Despite being relatively distant from the coast, Coimbra also has a marked Atlantic influence due to the floodplain of the Mondego River which crosses the city, making both its winters and summers milder than they would otherwise be. This influence also makes cold waves less frequent and less intense, however, days with minimum negative temperatures and cold waves are still present occasionally. Topography is also an important factor to consider in regard to nighttime temperatures, the presence of cold air lakes, in topographically depressed areas at certain synoptic situations, can also lead to pronounced colder temperatures.