Method
How we built the Denver data
The Denver data page draws on three public datasets, all free to download. One script fetches them; another boils them down into a single JSON file; the pages are generated from that file. No figure on the page was keyed in by a person.
Housing figures (American Community Survey)
We query api.census.gov for the 2020-2024 ACS 5-year estimates (release 2024) across 28 ZIP Code Tabulation Areas that together cover the City and County of Denver, a few of which spill into neighboring cities. For the four suburbs we switch to the Census "place" geography, which matches each city's own boundary.
- Share renting: B25003_003 divided by B25003_001.
- Arrived 2020 or later: B25038 cells 003 and 004 plus 010 and 011 (owners and renters whose householder moved in during 2020 to 2022, or 2023 on), divided by occupied units.
- Pre-1960 housing: B25034 cells 009 through 011, which cover 1959 and earlier, divided by B25034_001. The pre-1980 share also counts cells 007 and 008.
- Units in buildings of 10+: B25024 cells 007 through 009 divided by B25024_001.
- Households without a vehicle: B25044 cells 003 and 010 divided by B25044_001.
- Median build year: B25035_001 as published.
Caveats: a 5-year ACS estimate is an average of five years of sampling, and its error band widens as the area shrinks. ZIP boundaries ignore neighborhood boundaries, so treat our area labels as approximate.
Crime figures (FBI Crime Data Explorer)
We pull the summarized burglary and motor vehicle theft series (counts, plus rates per 100,000) from 2010 to 2025 for three agencies: Denver Police (ORI CODPD0000), Aurora Police (CO0010100) and Lakewood Police (CO0300400). A year is dropped if any month is missing. Each agency reports only what happens inside its own city, so read these as city numbers, never metro ones.
Weather figures (NOAA NCEI)
We use daily TMIN and TMAX plus snowfall from GHCND station USW00003017 at Denver International Airport, the station of record for Denver. For each year with at least 350 reported days in 2016 to 2025 (10 years), we count nights with a low at or under 32°F, days with a high at or under 32°F, and nights at or under 0°F, then average across years. The monthly chart uses those same years. DIA sits out on the plains northeast of town and is often a few degrees colder than Capitol Hill.
How often it updates
Once a month a scheduled job fetches all three sources again, regenerates the JSON file and hashes it. If the hash matches last month's, nothing happens; if it differs, the pages are rebuilt and the date at the top of this page moves. The Census publishes new ACS years in December, and the FBI posts annual crime data in the fall.
Citing the data
Denver Key Line, "Denver lock data by ZIP," https://denverkeyline.com/denver-lock-data/, data as of October 28, 2026. Sources: US Census Bureau ACS 2020-2024; FBI Crime Data Explorer; NOAA NCEI.