Castle Rock, ND climate
Castle Rock has cold winters and pleasant summers, with very little rain. A typical July afternoon reaches 84°, a January night drops to 5°.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Castle Rock feels like
Winter
Spring
Summer
Fall
Castle Rock weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 26° | 5° | 0.4" | 6° – 29° |
| February | 30° | 9° | 0.4" | -1° – 31° |
| March | 42° | 19° | 0.7" | 18° – 44° |
| April | 55° | 29° | 1.4" | 35° – 49° |
| May | 66° | 40° | 2.6" | 48° – 59° |
| June | 76° | 50° | 3.0" | 58° – 67° |
| July | 84° | 56° | 2.5" | 61° – 76° |
| August | 83° | 54° | 1.8" | 63° – 74° |
| September | 73° | 44° | 1.4" | 52° – 64° |
| October | 56° | 31° | 1.4" | 37° – 49° |
| November | 41° | 19° | 0.6" | 17° – 39° |
| December | 29° | 9° | 0.4" | 6° – 27° |
| Year | 55° | 30° | 16.6" |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Castle Rock
Castle Rock gets 17 inches of rain and melted snow a year. June is the wettest month and January the driest.
About 129 frost-free days a year
In half of years the last 32° night comes by May 16 and the first one by September 25. That leaves about 129 frost-free days for gardens, shorter than 95% of U.S. towns.
Heating and cooling a home in Castle Rock
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Castle Rock, 95% of that work is heating and 5% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Castle Rock and its neighbors
Castle Rock borders 6 towns with climate data. January nights across them vary by 0.7°. Mott has both the coldest January nights (5°) and the hottest July afternoons (84°). Castle Rock’s January low is 5° and its July high 84°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Castle Rock compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Castle Rock averaged 1.6° warmer than the 1900s. The biggest change is in January (+4.4°). The shift is larger than in 75% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Castle Rock’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from -1° to 31°. June is the most reliable, staying within 9°.
Common questions about Castle Rock’s climate
What is the coldest month in Castle Rock?
January, with a typical high of 26° and a low of 5°.
What is the hottest month in Castle Rock?
July, with a typical high of 84° and a low of 56°. About 30 days a year reach 90°.
When is the first frost in Castle Rock?
In half of years the first 32° night comes by September 25, and the last spring frost by May 16.
What is the rainiest month in Castle Rock?
June, with 3.0 inches of rain and melted snow. The year totals 17 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Castle Rock itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Mott, ND (4 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.