How ChillSemester works, and how much to trust it

Where the data comes from

• Classes, times, rooms and seats come from CUNY's public Global Search, the same pages you can open yourself. We read them politely and slowly.
• Professor numbers come from Rate My Professors: the rating, difficulty, would-take-again percentage and number of ratings. We never copy or show review text.
• Registration dates are read from each college's own calendar or registration page, linked from the dates page. When a college has not published one, we say so instead of guessing.
• We never ask for your CUNYfirst login and never register for classes for you. You always enroll yourself.

How fresh it is

A background job keeps re-reading the whole catalog, college by college, around the clock. Every class page shows the time its seat status was last confirmed (“Seat status as of…”), so you can judge it yourself. Seats can still change between refreshes, which is why a class marked open can be full a minute later.

Right now, for Spring 2027: 100% of the 26,978 sections were confirmed in the last 24 hours, and 90% in the last 6 hours. (Live numbers; they update as the refresh runs.)

Ratings are re-checked about once a month and before each registration period. Registration dates are re-checked as colleges publish them.

How seat alerts are checked

• An alert watches a full class and emails you when it opens a seat. That is the only event a seat alert tracks.
• Watched classes are re-checked about every 2 minutes while that college's registration is open, and about every 45 minutes the rest of the time.
• Separately, a registration reminder (free) emails you before your registration date and warns you if every section of a class you picked fills up. It does not tell you when a full class opens again; a seat alert does.
• Alerts are best effort. Another student can take the seat first, and we cannot guarantee delivery. Do not rely on any single tool for a class you must have.

Professor ratings

The Chill Rank blends difficulty, overall rating and would-take-again. A professor needs at least 3 ratings to get one, and we skip a match when a name could belong to two people rather than show the wrong professor. Details, and how many professors are covered right now, are on the rankings page.

Your degree audit

• The PDF is read once, in memory, and never stored.
• We keep only the courses, grades and open requirements it lists, tied to your account and visible only to you. Your name and student ID are discarded.
• You can delete the saved audit, or your whole account, yourself at any time. Full details are in the privacy policy.
• Degree Works can be wrong or incomplete, and so can our reading of it. Corrections are built in, and your advisor has the final word.