Mission Viejo, CA climate
Mission Viejo has warm winters and pleasant summers, with very little rain. A typical July afternoon reaches 83°, a January night drops to 47°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Mission Viejo feels like
Winter
Spring
Summer
Fall
Mission Viejo 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 | 68° | 47° | 2.6" | 0 | 6 | 0 | 54° – 63° |
| February | 67° | 47° | 3.1" | 0 | 7 | 0 | 51° – 65° |
| March | 69° | 48° | 1.9" | 0 | 5 | 0 | 52° – 66° |
| April | 72° | 50° | 0.7" | 0 | 3 | 0 | 57° – 65° |
| May | 74° | 54° | 0.2" | 0 | 2 | 0 | 59° – 70° |
| June | 78° | 57° | 0.1" | 0 | 1 | 0 | 64° – 72° |
| July | 83° | 61° | 0.0" | 0 | 1 | 0 | 69° – 78° |
| August | 86° | 62° | 0.0" | 0 | 0 | 0 | 71° – 77° |
| September | 85° | 61° | 0.1" | 0 | 1 | 0 | 69° – 76° |
| October | 79° | 56° | 0.5" | 0 | 2 | 0 | 63° – 73° |
| November | 73° | 51° | 0.8" | 0 | 3 | 0 | 56° – 66° |
| December | 67° | 46° | 2.0" | 0 | 6 | 0 | 54° – 63° |
| Year | 75° | 53° | 12.1" | 0.0" | 35 | 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 Mission Viejo
Mission Viejo gets 12 inches of rain and melted snow a year. February is the wettest month and August the driest. Rain or snow falls on about 35 days a year.
A year-round growing season
Heating and cooling a home in Mission Viejo
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Mission Viejo, 41% of that work is heating and 59% 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.
Mission Viejo and its neighbors
Mission Viejo borders 7 towns with climate data. January nights across them vary by 0.9°. Lake Forest has the coldest January nights (47°) and Rancho Santa Margarita the hottest July afternoons (86°). Mission Viejo’s January low is 47° and its July high 83°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Mission Viejo 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 Mission Viejo averaged 2.0° warmer than the 1900s. The biggest change is in January (+3.1°). The shift is larger than in 93% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Mission Viejo’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 51° to 65°. August is the most reliable, staying within 6°.
Common questions about Mission Viejo’s climate
What is the coldest month in Mission Viejo?
December, with a typical high of 67° and a low of 46°.
What is the hottest month in Mission Viejo?
August, with a typical high of 86° and a low of 62°. About 30 days a year reach 90°.
How much snow does Mission Viejo get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Mission Viejo?
Frost is uncommon. Only 3% of years see a night at 32° or below.
What is the rainiest month in Mission Viejo?
February, with 3.1 inches of rain and melted snow. The year totals 12 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mission Viejo itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Santa Ana Fire Stn, CA (15 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.