We humans define the seasons by the solar cycle or by our own, somewhat arbitrary calendar. According to the first, more natural definition, the seasons stretch between the solstices and the equinoxes while, on the latter, each is assigned a three month block, based on cultural and religious tradition.
It is, of course, the tilt of Earth's axis that produces our seasonal change, as the angle of sunlight (and subsequent surface heating) varies through the year. While there is limited annual solar variation in the Tropics, there is a dramatic seasonal change at the poles, with periods of perpetual light and darkness; between these extremes, the seasonal variance correlates with latitude but may also be affected by ocean currents or the proximity to large bodies of water, which moderate conditions on the adjacent land.
Nevertheless, as we all know, seasonal weather expectations, based on long term observations, are not always met. Stagnant weather patterns or sudden shifts in the jet stream can produce a spring without rain, a chilly summer or a week of balmy days in the midst of winter. While our wild neighbors respond primarily to the light cycle and readily adapt to changing conditions, we humans are prone to emotional turmoil when the weather and seasons are out of sync. Unfortunately, nature is oblivious to human expectations and we must accept (if not cherish) her whimsical temperament.
