(1) The seasons on Mars are similar to those on Earth, but colder, because it is further from the Sun, and longer, because its year is longer than ours.
(2) Because of Mars' nearly 10% eccentricity, and lack of oceans, there is a noticeable difference between perihelion summer and aphelion summer, both in temperature, and the number and intensity of dust storms.
(3) Because of Mars' nearly 10% eccentricity, its seasons have very unequal length. Even for the Earth, there is a difference of a few days in the lengths of the seasons; but on Mars, the differences are measured in months, not days.