The four anime seasons, which are what people actually mean by "this season".
Anime is published in quarters — winter, spring, summer, fall — and talked about that way: a show is "a Summer 2026 anime", and the thing you want to browse is the whole quarter. "The previous season" is no use as a label; a list is only navigable if it says Summer 2026.
A season is its premiere window, which is also how the charts everyone reads are built: a show belongs to the quarter it started in.
Summary
Functions
Every season name, in order.
The season happening now, as {year, season}.
Human label, as everyone writes it: "Summer 2026".
The season after this one.
Which season a month falls in.
The season before this one.
This season and the ones before it, newest first — [{2026, :fall}, {2026, :summer}, …]. Counting back across a year boundary lands in the previous
year's fall, which is what a reader expects to see next.
The premiere window as {from, to} ISO dates — a show belongs to the season
it started in, which is how every seasonal chart is built.
Functions
Every season name, in order.
The season happening now, as {year, season}.
Human label, as everyone writes it: "Summer 2026".
The season after this one.
Which season a month falls in.
The season before this one.
This season and the ones before it, newest first — [{2026, :fall}, {2026, :summer}, …]. Counting back across a year boundary lands in the previous
year's fall, which is what a reader expects to see next.
The premiere window as {from, to} ISO dates — a show belongs to the season
it started in, which is how every seasonal chart is built.