Air & Temperature · 24 hours
Scroll through one summer day in a Colorado housing unit, from before dawn to after lockdown. Watch the heat outside, in the dayroom, and in a top-tier cell, and see which rules apply at each hour.
Illustration Built from published engineering methods and Colorado's own rules, not measured in any one prison. The daily schedule comes from Michael Clifton's years inside; it varies by facility and custody level. Every assumption is listed at the end.
Colorado nights cool off fast in dry air. Inside, the concrete is still holding yesterday's heat, so the cell lags far behind the cool morning outside.
Once cell doors open, dayroom air can reach the cells. This is when the cooler morning air helps most, if the system is pulling it in.
An open door is not freedom. People can reach the pod to shower, use the microwave or watch TV, but usually not the sally port or anywhere outside the unit.
From Michael Clifton, 24½ years in Colorado prisons, including Limon and Sterling
Most Colorado facilities now run controlled movement: you need a pass and staff approval to go anywhere, and you get about five minutes to get from one place to the next. People used to be able to push the button and walk out to yard during yard hours. Getting out of a hot unit is no longer a choice you make.
From Michael Clifton, 24½ years in Colorado prisons, including Limon and Sterling
On days forecast to reach 90°F, the work-crew supervisor checks the heat index. Strenuous yard activity stops only when the heat index reaches 105°F.
AR 850-17: alert at a 105°F heat index · heat index outside right now: — · read the rule
In dry air, this is when a swamp cooler works best: the drier the air, the more water it can evaporate. On a humid afternoon it falls behind.
6 CCR 1010-13 §9.4: indoor temperature must stay under 86°F in the warmest months · read the rule
Sun has heated the roof and walls all afternoon. That heat keeps flowing into the top tier long after the outside air starts to cool.
Doors close. Lockdown has moved over the years, from 9 PM to 10 PM and back to 9 PM; around 9 is common now. In a cell with no vent of its own, the only air comes through the door gaps, so the cell stops sharing the dayroom's cooling. People inside have described swamp coolers doing little for the cells after lockdown.
Reported at Fremont CF: Prison Journalism Project, 2023
Outside has cooled by 20 degrees or more. The top-tier cell cools far more slowly, because the concrete gives back the heat it stored all day. In restrictive housing, a fan isn't on the property list at all.
AR 850-06: one fan allowed in general population; none in restrictive housing designations · read the rule
The whole day, with your settings
Either way, CDOC's heat rule measures the yard, not the cell. Nothing in it records how hot a housing unit gets, so no one can say from public records which of these days a real prison is having.
| What | Value used | Where it comes from |
|---|---|---|
| Outside temperature | Dry July day: low 62°F, high 95°F, dew point 45°F. Heat spell: 68°F / 100°F, dew point 48°F. Humid afternoon: 64°F / 90°F, dew point 58°F. Coolest at 5 AM, hottest at 3 PM. | Example days chosen to match typical Front Range and Arkansas Valley summers; not a specific date |
| Swamp cooler output | Working well: closes 80% of the gap between air temperature and wet-bulb temperature. Warm air can't get out: 45%, more moisture indoors, +2°F | Standard evaporative cooling method; same as the Air & Temperature cutaway |
| Air conditioning | Holds the dayroom near 76°F at about 50% humidity | Typical comfort setting; illustrative |
| People and lights | +4°F in the dayroom | Illustrative |
| Top-tier cell | +6°F over the dayroom with door gaps only, +2°F with its own vent; up to +3°F more from the sun on the roof in late afternoon | Illustrative: heat rises; roof and sun-side wall add heat |
| After lockdown | +2°F more in a cell with door gaps only | Illustrative: the cell stops sharing dayroom air |
| Concrete holds heat | Indoor air moves toward its target with a 3-hour lag (cells 4 hours) | Illustrative: heavy masonry buildings respond slowly |
| Schedule | Pod doors open 6:00 AM, lockdown 9:00 PM; controlled movement in between | Michael Clifton's firsthand account; varies by facility and custody level, and time out of cell has shrunk over the years |
| Heat index | Temperature plus humidity | National Weather Service formula |