Autumn/fall (okay, since I'm on the topic. "Fall" is a silly word. It means something else, people. Having it both as the name of a season and "to drop or come down freely under the influence of gravity" makes things unnecessary confusing. "That was a great fall!"). Autumn/fall is for me the season most closely tied with the United States. Partly, it's because when I was there, I experienced fall (of the seasonal and not gravital kind). I saw beautiful foliage in several parts of the country, I tasted fall specialties such as pumpkin pie or candy corn, and I witnessed stores decorate for the most American of holidays: Halloween and Thanksgiving. Even before I visited the US, however, it was firmly established that fall is the "national" season.
All these things considered, I don't think it's surprising that it is during this time of year I mostly want to go back. I want to celebrate Halloween, the American way (would you BELIEVE that I left the country the day before Halloween?!). I want to hang out with a stereotypical sit-com family that watch football on TV while mom cooks the turkey for Thanksgiving. I want to have more pumpkin pie (even though I didn't like it much). I want to walk along a Minnesota field while admiring the colourful forest ahead. I want to smell stuff like maple and cinnamon and other things comprised into "pumpkin spice" in a Starbucks latte.