Castle Rock, Colorado Weather
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Climate of Castle Rock: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Castle Rock, with average daytime highs around 30°C. December is the coolest, when nights typically fall to about -8°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 38°C, so the seasons feel very different from each other.
The area receives about 440 mm of rain in a typical year. Rainfall is modest in every month; July is the wettest at about 62 mm. The driest stretch is November to January, with under 20 mm a month.
For outdoor plans and travel, June to September usually offer the most comfortable weather in Castle Rock, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 4° | -7° | 17 mm | 55% |
| Feb | 5° | -8° | 21 mm | 56% |
| Mar | 10° | -4° | 34 mm | 52% |
| Apr | 15° | -1° | 51 mm | 50% |
| May | 21° | 4° | 58 mm | 49% |
| Jun | 28° | 11° | 42 mm | 41% |
| Jul | 30° | 15° | 62 mm | 45% |
| Aug | 28° | 13° | 52 mm | 46% |
| Sep | 24° | 8° | 36 mm | 44% |
| Oct | 17° | 1° | 30 mm | 48% |
| Nov | 10° | -4° | 18 mm | 51% |
| Dec | 4° | -8° | 19 mm | 56% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Castle Rock. Values describe typical conditions, not a forecast.
About Castle Rock weather
Castle Rock is set in Colorado's high-altitude climate, ranging from semi-arid plains to alpine mountains, about 42 km south of Denver. Summers bring warm days and cool nights (June–August), especially at altitude. The year winds down with cold, snowy winters in the mountains, milder on the eastern plains. This page shows live, auto-refreshing weather for Castle Rock: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Denver.
Frequently asked questions
Castle Rock is about 42 km south of Denver, in Colorado.
Castle Rock sees cold, snowy winters in the mountains, milder on the eastern plains.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Castle Rock's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Castle Rock, with average daytime highs of about 30°C and nights around 15°C.
The coldest nights come in December, when the average low is about -8°C and daytime highs reach around 4°C. Frost is possible on clear, calm nights.
Castle Rock receives about 440 mm of rain in a typical year. July is the wettest month at roughly 62 mm; no month averages more than 100 mm.
June to September usually offer the most comfortable weather in Castle Rock, with mild daytime temperatures and little rain.
In November Castle Rock typically sees daytime highs near 10°C and lows near -4°C, with about 18 mm of rain over the month and average humidity around 51%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
Live temperature for Castle Rock is shown at the top of this page and refreshes automatically — see the hourly breakdown below for how it changes through the day.
Castle Rock's day-to-day weather follows the broader pattern of Colorado described above. See the hourly weather forecast or the air quality index for more detail.