Hot sake, which I always will associate with the New Year and winter in Japan.
In America, we have some things which are similar to seasonal food in Japan, though they tend to be tied to specific holidays rather than the calendar or weather. Marketers are also constantly trying to expand the timeline on everything. I recall, for instance, when marshmallow peeps were available only at Easter and only as, well, peeps and not other types of critters. In Japan, though you can get certain foods year-round, there are seasons for eating particular dishes regardless of availability because the culture throughout the centuries associates them with a particular time frame. There was something about these consistent patterns that added to the sense of the rhythm of life and made you take notice of the time passing. It is similar to the way eating pumpkin pie used to make people remember the warmth of family around Thanksgiving (or the fighting and screaming depending on your family) before pumpkin pie became a food to be consumed year round.
I miss the way the food matched the seasons with predictable regularity.
If you'd like to see some very brief idyllic commercials for season sweets, you can watch one for each here (at least at the time of this posting, the link is valid).