Beverly aggravated assault rose 86% against its multi-year baseline, the strongest single signal in Chicago this briefing and the first time this neighborhood has topped the citywide rankings. The move stands out against an otherwise broadly declining month, making it the clearest fresh story in September 2026.
Citywide volume is down 3.7% against the prior 12 months, 128,894 incidents against 133,803. The signal mix leans toward stability: 49 sustained-shift signals and 34 below-trend signals against 10 fresh spikes across 77 neighborhoods. Sexual assault registered fresh spikes in three neighborhoods, Lower West Side, West Pullman, and Douglas, a category-level pattern that sits alongside the Beverly aggravated assault move as the second thread worth tracking.
The Beverly result is new to the top of the rankings, so there is no multi-month run to contextualize it. The sexual assault pattern across three neighborhoods is the more structurally notable element: three separate areas showing the same move in the same month is a signal worth watching in October. Otherwise, the sustained-shift and drop signals continue to outnumber spikes nearly eight to one, and the multi-year decline in citywide volume holds.
Sustained drops worth naming
Robbery ran below trend in the trailing 12 months — 29% down from the year before. Sustained shifts often precede a baseline reset; we surface them at the same prominence as spikes.
How last month's forecasts performed
Forecasts for September were issued from data through August 2026. 9 of 9 citywide bucket forecasts (100%) landed inside their 95% prediction intervals.
| Category | Predicted | Actual | Error | In CI |
|---|---|---|---|---|
| Aggravated Assault | 1101[983–1219] | 1093 | 0.7% | INSIDE |
| Arson | 37[21–53] | 36 | 1.7% | INSIDE |
| Burglary | 550[365–729] | 501 | 9.8% | INSIDE |
| Homicide | 44[23–63] | 31 | 40.6% | INSIDE |
| Motor Vehicle Theft | 1998[1145–2940] | 1431 | 39.6% | INSIDE |
| Other Larceny | 5622[4565–6701] | 4667 | 20.5% | INSIDE |
| Robbery | 484[283–696] | 414 | 16.9% | INSIDE |
| Sexual Assault | 272[238–306] | 283 | 3.7% | INSIDE |
| Vandalism | 2200[1969–2435] | 2100 | 4.8% | INSIDE |
Per-bucket coverage, MAPE, and bias across the full 12-month horizon live on the methodology page.
Public Analyst.ai, “September 2026 — Chicago,” archived snapshot.Permanent URL: /chicago/2026/september