April is one of the cooler months of the year in Castle Rock, with average highs near 14.7°C and lows around -0.8°C (mean 7°C). It is a relatively wet time of year, averaging 50 mm of rainfall and 50% relative humidity across the period.
April is one of the cooler months of the year in Castle Rock. Across 45 years of records, the warmest April in Castle Rock was 1981 — when the month averaged 10.6°C — while the coldest was 1983 at 2.6°C. Typical April days reach 14.7°C with nights near -0.8°C. The long-term April temperature trend is broadly flat.
April is a relatively wet time of year in Castle Rock, averaging 50 mm of rainfall. The wettest April on record was 1999 with 158 mm, while the driest was 2002 at 6 mm.
Relative humidity in Castle Rock during April averages 50%. The most humid April was 1983 at 62%, and the least humid was 2022 at 37%.
April receives about 5.8 kWh/m²/day of solar energy in Castle Rock. The sunniest April was 2002 at 6.5 kWh/m²/day, and the cloudiest were 2005, 2009 and 2016, among others at 5.2.
Average wind speed in Castle Rock during April is 2.9 m/s. The windiest Aprils were 1984 and 2022 at 3.5 m/s, while the calmest was 2019 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 7.0°C | 6.0°C | 7.7°C | 7.1°C | 7.3°C | +0.3°C |
| Avg High | 14.6°C | 13.3°C | 15.7°C | 14.9°C | 15.4°C | +0.8°C |
| Avg Low | -0.7°C | -1.3°C | -0.3°C | -0.7°C | -0.8°C | -0.1°C |
| Avg Rain | 41 mm | 65 mm | 52 mm | 50 mm | 36 mm | -5 mm |
April temperatures in Castle Rock have risen by about 1.2°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -13°C (2013) to a record high of 28°C (2012).
Rainfall in April is a relatively wet time of year, averaging 50 mm, with a wettest year of 158 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.3°C per decade while lows rose 0°C per decade, widening the gap between day and night.
A good time to visit Castle Rock
April is a good time to visit Castle Rock, with days averaging 14.7°C and nights around -0.8°C (mean 7°C, cooler than Castle Rock's yearly average) and moderate rainfall. July and August are marginally more temperate, but April still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 16.6°C | 8.3°C | 0.0°C | 27.6°C | -8.1°C | 26 mm | 46% | 2.7 m/s | 5.9 |
| 2024 | 16.3°C | 8.4°C | 0.5°C | 24.0°C | -4.4°C | 60 mm | 50% | 3 m/s | 6 |
| 2023 | 14.8°C | 6.7°C | -1.4°C | 26.5°C | -8.5°C | 41 mm | 45% | 2.6 m/s | 6 |
| 2022 | 16.0°C | 7.6°C | -0.7°C | 25.8°C | -7.2°C | 10 mm | 37% | 3.5 m/s | 6.4 |
| 2021 | 14.3°C | 6.1°C | -2.2°C | 23.8°C | -10.3°C | 49 mm | 50% | 2.6 m/s | 5.6 |
| 2020 | 14.4°C | 6.6°C | -1.3°C | 26.8°C | -10.9°C | 29 mm | 50% | 2.4 m/s | 5.9 |
| 2019 | 15.8°C | 8.0°C | 0.2°C | 24.0°C | -8.0°C | 30 mm | 53% | 2.3 m/s | 5.4 |
| 2018 | 15.6°C | 7.5°C | -0.7°C | 24.9°C | -5.7°C | 29 mm | 45% | 3.3 m/s | 6.1 |
| 2017 | 15.2°C | 7.4°C | -0.5°C | 24.9°C | -8.9°C | 49 mm | 50% | 2.9 m/s | 5.8 |
| 2016 | 13.0°C | 5.9°C | -1.2°C | 22.6°C | -9.5°C | 79 mm | 58% | 2.9 m/s | 5.2 |
| 2015 | 15.4°C | 7.5°C | -0.4°C | 23.3°C | -4.7°C | 71 mm | 51% | 2.5 m/s | 5.8 |
| 2014 | 14.0°C | 6.5°C | -0.9°C | 23.7°C | -10.8°C | 45 mm | 52% | 3.2 m/s | 5.6 |
| 2013 | 12.1°C | 4.3°C | -3.6°C | 24.2°C | -13.0°C | 46 mm | 53% | 2.9 m/s | 5.4 |
| 2012 | 18.7°C | 10.2°C | 1.8°C | 28.0°C | -4.0°C | 41 mm | 43% | 2.8 m/s | 6.4 |
| 2011 | 14.7°C | 6.9°C | -0.9°C | 22.5°C | -6.9°C | 42 mm | 47% | 3.4 m/s | 5.7 |
| 2010 | 14.4°C | 6.8°C | -0.7°C | 22.2°C | -5.7°C | 69 mm | 53% | 3.4 m/s | 5.9 |
| 2009 | 13.8°C | 6.2°C | -1.4°C | 23.2°C | -9.6°C | 95 mm | 55% | 3.2 m/s | 5.2 |
| 2008 | 13.9°C | 5.7°C | -2.5°C | 23.2°C | -8.6°C | 30 mm | 44% | 3.2 m/s | 6.4 |
| 2007 | 14.0°C | 6.5°C | -1.1°C | 25.5°C | -6.3°C | 74 mm | 56% | 2.9 m/s | 5.5 |
| 2006 | 18.1°C | 9.6°C | 1.1°C | 26.3°C | -6.2°C | 21 mm | 40% | 3.1 m/s | 6.1 |
| 2005 | 14.8°C | 7.0°C | -0.8°C | 23.1°C | -7.1°C | 76 mm | 53% | 3 m/s | 5.2 |
| 2004 | 14.1°C | 6.9°C | -0.2°C | 23.6°C | -8.3°C | 86 mm | 55% | 3 m/s | 5.4 |
| 2003 | 15.9°C | 8.3°C | 0.7°C | 24.5°C | -5.9°C | 54 mm | 49% | 3.1 m/s | 6 |
| 2002 | 18.8°C | 9.9°C | 0.9°C | 26.3°C | -7.0°C | 6 mm | 37% | 2.9 m/s | 6.5 |
| 2001 | 16.8°C | 8.5°C | 0.1°C | 24.6°C | -5.8°C | 42 mm | 47% | 3 m/s | 5.9 |
| 2000 | 17.1°C | 8.6°C | 0.2°C | 25.2°C | -9.6°C | 36 mm | 47% | 3 m/s | 5.9 |
| 1999 🌧️ | 11.4°C | 4.4°C | -2.6°C | 21.4°C | -12.3°C | 158 mm | 58% | 3.3 m/s | 5.2 |
| 1998 | 11.3°C | 4.5°C | -2.4°C | 22.9°C | -6.9°C | 71 mm | 60% | 2.5 m/s | 5.9 |
| 1997 | 10.7°C | 3.7°C | -3.4°C | 21.5°C | -12.8°C | 76 mm | 58% | 2.6 m/s | 5.6 |
| 1996 | 14.4°C | 6.7°C | -0.9°C | 23.9°C | -7.4°C | 36 mm | 49% | 3.2 m/s | 5.9 |
| 1995 | 11.5°C | 4.5°C | -2.5°C | 20.4°C | -10.7°C | 89 mm | 57% | 2.8 m/s | 5.2 |
| 1994 | 13.7°C | 6.4°C | -0.9°C | 24.9°C | -8.1°C | 62 mm | 56% | 2.7 m/s | 5.4 |
| 1993 | 13.1°C | 5.7°C | -1.7°C | 21.7°C | -5.7°C | 51 mm | 57% | 2.7 m/s | 5.9 |
| 1992 | 17.8°C | 10.0°C | 2.1°C | 27.3°C | -5.9°C | 17 mm | 48% | 2.4 m/s | 6.2 |
| 1991 | 13.9°C | 6.3°C | -1.4°C | 25.3°C | -6.6°C | 47 mm | 49% | 2.5 m/s | 5.7 |
| 1990 | 14.9°C | 7.7°C | 0.5°C | 23.1°C | -5.8°C | 43 mm | 56% | 2.7 m/s | 5.3 |
| 1989 | 16.1°C | 8.2°C | 0.4°C | 27.6°C | -11.4°C | 34 mm | 45% | 2.9 m/s | 5.5 |
| 1988 | 16.1°C | 7.9°C | -0.4°C | 24.8°C | -9.2°C | 25 mm | 49% | 2.8 m/s | 5.7 |
| 1987 | 15.8°C | 8.0°C | 0.3°C | 25.3°C | -7.6°C | 28 mm | 49% | 3.1 m/s | 6.1 |
| 1986 | 15.2°C | 7.5°C | -0.2°C | 23.6°C | -10.1°C | 67 mm | 54% | 3.1 m/s | 5.8 |
| 1985 | 15.9°C | 8.2°C | 0.4°C | 24.3°C | -5.6°C | 59 mm | 52% | 2.7 m/s | 5.5 |
| 1984 | 10.6°C | 3.7°C | -3.2°C | 21.0°C | -7.0°C | 66 mm | 58% | 3.5 m/s | 5.4 |
| 1983 ❄️ | 8.9°C | 2.6°C | -3.7°C | 21.7°C | -12.8°C | 48 mm | 62% | 2.6 m/s | — |
| 1982 | 13.9°C | 5.9°C | -2.0°C | 20.9°C | -7.3°C | 20 mm | 42% | 3.2 m/s | — |
| 1981 🔥 | 18.9°C | 10.6°C | 2.2°C | 27.2°C | -6.6°C | 19 mm | 42% | 2.7 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 14.7°C with lows near -0.8°C (mean 7°C), based on 45 years of NASA POWER data.
April averages 50 mm of rainfall in Castle Rock, a relatively wet time of year. The wettest on record was 158 mm in 1999.
The hottest April reached 28°C in 2012. The coldest dipped to -13°C in 2013.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 1.2°C. Daytime highs moved from 13.6°C to 15.6°C and overnight lows from -1.3°C to -0.8°C over the same span.
April is one of the cooler months of the year in Castle Rock and a relatively wet time of year, so plan for around 14.7°C daytime highs and -0.8°C at night.
Not quite — April is the 6th coolest month in Castle Rock, averaging 7°C.
For April in Castle Rock, pack warm layers and a jacket for chilly mornings, with typical highs of 14.7°C and lows of -0.8°C.
Relative humidity in April averages 50% — relatively dry.
Average wind speed in April is 2.9 m/s. The windiest April on record averaged 3.5 m/s (1984).
The wettest April on record was 1999 with 158 mm. On average, April sees 50 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Castle Rock behaves each April, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for April specifically, along with year-by-year records and how the month has changed over the decades.
