An occluded front is a combination of both a cold and a warm front.

Note: A front is shown as a line on a weather chart that represents the front's surface position. An occluded front is represented by a combination of semicircles (warm front symbol) and barbs (cold front symbol) along the front line.

An occlusion occurs because the cold front moves faster than the warm front, and therefore, the cold front inevitably will catch up with the warm front. This occurs first near the centre of the depression, where the original distance between the two fronts is the shortest.

The characteristic weather of the two fronts also becomes combined. However, because temperatures between the cold air behind the warm sector and the cold air in front of the warm sector are never the same, the type of occlusion will be either a warm or cold occlusion.