When Chicago calls

Most of what city government does happens in daylight, on a regular shift schedule. Some of what residents notice doesn't. A pothole is a pothole at noon and at 3 a.m., but only one of those gets reported — at the hour the reporter is awake, walking past it, in a car on that block. The Chicago 311 record carries an exact timestamp on every call. Charted as a 24-hour cycle, those timestamps reveal which categories of complaint follow the workday and which follow the city's actual lived rhythm.

Below is the shape of one category: Street Light Out. Each slice of the dial is one hour; the further from center, the more reports that landed in that slot. Since January 2024, residents have filed 88,651 of these. The peak — 9 p — is when the city is dark and most people are still up. This is the shape of a complaint that requires darkness to be visible.

Four rhythms, one dial

Add three more categories and the contrast sharpens. Concentric rings now show, from outer in: Street Light Out (the night-skewed shape we just saw), Rodent Baiting (a morning-shift dispatch shape — the calls come in when sanitation crews log them, not when rats are seen), Graffiti Removal (a long afternoon plateau — daylight tagging traces, daylight reports), and Aircraft Noise (a bimodal commute shape, tracking O'Hare's morning departures and evening arrivals).

Four request types, four mechanisms, four shapes. The "city's hour" is not one hour — it's a layered set of rhythms whose peaks are hours apart.

When each rhythm peaks

Sorted by peak hour, the four shapes line up across the day. The morning shift owns Rodent Baiting; the afternoon owns Aircraft Noise (the first lobe of its commute pattern) and Graffiti; the evening owns Aircraft Noise again (the second lobe); and the late evening owns Street Light Out.

The geography of the night shift

The dial says when. It can't say where. Filtering Street Light Out down to the late-night window (10 p.m. through 4 a.m.) and projecting it onto Chicago's 77 community areas surfaces a familiar map: the West and South sides carry the heaviest concentration of after-dark streetlight reports. Area 25, Area 24, and Area 8 top the list.

Whether that reflects more outages or just more noticed outages is the question every 311-based map has to answer. A streetlight out in a quiet block on the Northwest Side and one on a busy stretch of Pulaski Road have very different odds of being called in by 2 a.m.

The dial is a question, not an answer. It says when residents file calls and when city workers process them — and those two things only sometimes coincide. Slice the underlying data yourself on the curated views page, or hit the SQL playground to write your own hour-of-day query against any of the city's sr_types.