Martian Seasons

Mars experiences seasons similar to Earth's due to the former's axial tilt (25 degrees compared to Earth's 23.5). During the Martian Year (approximately 29 Earth Months), Mars experiences four seasons, but due to Mars' highly eliptical orbit, the seasons have varied lengths compared to Earth's fairly equal seasons. Northern Spring/Southern Autumn is the longest month at about 194 Sols (Martian Days) and conversely the shortest season is the Northern Autumn/Southern Winter at 142 Sols. Northern Summer lasts 178 Sols and Northern Winter lasts 154 Sols.
Additionally, Mars' eliptical orbit means the aphelion and perihelion have a greater effect on the seasons. Mars is near aphelion during the Northern Summer/Southern Winter and perhelion during the Northern Winter/Southern Summer. As a result, the Southern Hemisphere experiences more extreme summers and winters.
The equatorial region experiences the most consistent weather, to include parts of the Mariner Valley Region at 13 degrees South. In the equatorial region, Aphelion/Perihelion has a greater influence on temperature and climate than the hemispheric seasons.
Two extended weather periods, colloquially called seasons, affect Mars at almost the same time each Martian year. The Dust Season lasts during the Spring and Summer for the Southern Hemisphere and therefore have the highest intensity in the South. The Wet Season for each Hemisphere centers around the Winter, with strongest precipitation towards late Autumn and the Spring thaw. These heavy rains often cause flash flooding and the proliferation of seasonal rivers, drastically altering the Martian landscape for their duration. During the Winter the subzero temperatures mean that most precipitation will be in the form of snowfall.