Castaic, CA climate
Castaic has warm winters and hot summers, with very little rain. A typical July afternoon reaches 93°, a January night drops to 41°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Castaic feels like
Winter
Spring
Summer
Fall
Castaic weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 64° | 41° | 4.4" | 0 | 6 | 0 | 48° – 60° |
| February | 65° | 41° | 5.1" | 0 | 6 | 0 | 45° – 62° |
| March | 69° | 44° | 3.1" | 0 | 5 | 0 | 49° – 64° |
| April | 74° | 46° | 0.9" | 0 | 2 | 0 | 54° – 65° |
| May | 79° | 51° | 0.4" | 0 | 1 | 0 | 56° – 72° |
| June | 87° | 56° | 0.0" | 0 | 0 | 0 | 65° – 77° |
| July | 93° | 61° | 0.0" | 0 | 0 | 0 | 71° – 83° |
| August | 95° | 62° | 0.0" | 0 | 0 | 0 | 75° – 82° |
| September | 90° | 59° | 0.1" | 0 | 1 | 0 | 70° – 79° |
| October | 81° | 52° | 0.7" | 0 | 2 | 0 | 62° – 72° |
| November | 71° | 45° | 1.0" | 0 | 3 | 0 | 48° – 62° |
| December | 63° | 40° | 3.0" | 0 | 5 | 0 | 47° – 58° |
| Year | 77° | 50° | 18.8" | 0.0" | 31 | 0 |
“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 Castaic
Castaic gets 19 inches of rain and melted snow a year. February is the wettest month and August the driest. Rain or snow falls on about 31 days a year.
A year-round growing season
Heating and cooling a home in Castaic
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Castaic, 47% of that work is heating and 53% is cooling.
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.
How Castaic 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 Castaic averaged 2.3° warmer than the 1900s. The biggest change is in January (+3.2°). The shift is larger than in 99% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Castaic’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 45° to 62°. August is the most reliable, staying within 7°.
Common questions about Castaic’s climate
What is the coldest month in Castaic?
December, with a typical high of 63° and a low of 40°.
What is the hottest month in Castaic?
August, with a typical high of 95° and a low of 62°. About 87 days a year reach 90°.
How much snow does Castaic get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Castaic?
Frost is uncommon. Only 37% of years see a night at 32° or below.
What is the rainiest month in Castaic?
February, with 5.1 inches of rain and melted snow. The year totals 19 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Castaic itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Piru 2 Ese, CA (9 mi, snow) and Newhall 5nw, CA (6 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.