Castle Rock, Colorado · winter 2026-27
Chill hours in Castle Rock this winter
Chill hours accumulated since 1 November
Hours at or below 45°F, running total. Grey: last winter; clay: this winter so far.
- Winter 2026-27
- Winter 2025-26
View as table
| Month | Chill hours (≤ 45°F) |
|---|---|
| November 2025 | 360 |
| December 2025 | 434 |
| January 2026 | 553 |
| February 2026 | 371 |
| Total | 1,718 |
Fruit trees need a set number of cold hours in winter before they bloom well. Nurseries rate varieties by it: low-chill varieties need roughly 100 to 400 hours, many peaches and plums 500 to 900, and most apples and sweet cherries 800 to 1,200 or more. Your variety's rating is the number to compare with the 1,718 hours Castle Rock had last winter.
Chill hours here are hours at or below 45°F, estimated hour by hour from the station's daily high and low. Checked against measured hourly air temperature at 39 NOAA reference stations last winter, the estimate was within 1.9% of the measured count at the median station. How it is checked.
Chill hours nearby
Each from a different station.
| City | Distance | Chill hours so far | Last winter |
|---|---|---|---|
| Denver, CO | 42 km | 49 | 1,597 |
| Brighton, CO | 68 km | 57 | 1,769 |
| Boulder, CO | 80 km | 70 | 1,523 |
| Cañon City, CO | 109 km | 54 | 1,476 |
| Greeley, CO | 118 km | 48 | 1,674 |
| Pueblo, CO | 126 km | 70 | 1,773 |
Questions
- How many chill hours has Castle Rock had this winter?
- 82 hours at or below 45°F from 1 November to Nov 8, 2026, estimated from the daily highs and lows at the Denver Centennial Airport station.
- How many chill hours did Castle Rock get last winter?
- 1,718 hours from 1 November to 28 February (2025-26).
- Which chill model is this?
- The simple 45°F model: every hour at or below 45°F counts. The 32 to 45°F count, which leaves out hours below freezing, is shown as well.
Data: Global Historical Climatology Network - Daily (GHCN-Daily), daily maximum and minimum temperature (NOAA National Centers for Environmental Information (NCEI)); GeoNames gazetteer (cities15000) (GeoNames).