What is the hottest month in Mission Viejo?

August is Mission Viejo's hottest month, with the highest average daily high of the year. The month-by-month table above shows Mission Viejo's exact average high and low for each month, based on the 1991–2020 climate normals — the standard 30-year reference period meteorologists use.

What is the coldest month in Mission Viejo?

December is Mission Viejo's coldest month, with the lowest average daily low of the year. The averages-by-month chart above gives the exact average high and low for every month, so you can see how cold a typical winter day runs.

How much does it rain in Mission Viejo?

Mission Viejo's total annual precipitation and its wettest and driest months are shown in the rainfall-by-month section above. Those figures are 1991–2020 normals — the average monthly precipitation total across that 30-year window — so they reflect a typical year rather than any single wet or dry season.

What months are best to visit Mission Viejo?

The most comfortable months in Mission Viejo are usually the shoulder seasons — spring and fall — when temperatures sit between the summer peak and winter low and rainfall is moderate. Compare the average high, low, and precipitation for each month in the table above to pick the window that fits the weather you want.

Has Mission Viejo gotten hotter?

There isn't enough data to say. The warming-stripes chart above plots Mission Viejo's annual mean temperature for every complete year of station data from 1949 to 2025, but no trend line is fitted: the latest stretch of complete years with no gap over 10 years is 2012–2025, only 11 years (a trend needs at least 30). A shorter or broken record can't separate a climate trend from normal year-to-year swings.

What is the record high temperature in Mission Viejo?

Mission Viejo's all-time record high — the hottest single day in the station record — is shown in the records section above, along with the date it occurred. Records are drawn from the nearest long-term weather station's full daily history, which begins in 1949, so they capture the most extreme heat on record, not just a typical summer day.

What is the record low temperature in Mission Viejo?

Mission Viejo's all-time record low and the date it was set appear in the records section above. Like the record high, it comes from the station's full daily history back to 1949, so it reflects the coldest day on record rather than an average winter low.

Mission Viejo, California Climate

Mission Viejo weather by month — average highs and lows, rainfall, all-time records, and the warming record since 1949

Hottest month: 95°FAugust average high
Coldest month: 37°FDecember average low
Precipitation: 10.7 ina year
Wettest month: February2.4 in on average

1991–2020 NOAA climate normals

At 7:15 AM PDT on Sep 21 it was 66°F in Mission Viejo — 8° above the 58°F typical for that hour (estimated from the Sep 21 normal high of 90°F and low of 57°F, interpolated from the monthly normals).

Mission Viejo weather by month

Average high, low, and rainfall for every month, from Mission Viejo’s 1991–2020 climate normals, the standard 30-year reference period. Each band runs from the month’s average low to its average high: a tall band is a big day-to-night swing.

66°37°

2.0″Jan

66°38°

2.4″Feb

71°40°

1.5″Mar

74°44°

0.8″Apr

80°51°

0.3″May

87°56°

0.1″Jun

94°62°

0.1″Jul

95°62°

0.4″Aug

92°59°

0.2″Sep

82°49°

0.5″Oct

72°41°

0.7″Nov

65°37°

1.8″Dec

Average high → low (°F)Rainfall (inches)1991–2020 normals

Mission Viejo monthly weather averages — average high, average low, and rainfall for each month, from the 1991–2020 U.S. Climate Normals (NOAA).
Month	Avg High	Avg Low	Rainfall
January	66°F	37°F	2.0 in
February	66°F	38°F	2.4 in
March	71°F	40°F	1.5 in
April	74°F	44°F	0.8 in
May	80°F	51°F	0.3 in
June	87°F	56°F	0.1 in
July	94°F	62°F	0.1 in
August	95°F	62°F	0.4 in
September	92°F	59°F	0.2 in
October	82°F	49°F	0.5 in
November	72°F	41°F	0.7 in
December	65°F	37°F	1.8 in
Annual	79°F	48°F	10.7 in

Mission Viejo’s warming record since 1949

No trend published: the latest stretch of complete years with no gap over 10 years is 2012–2025, only 11 years (a trend needs at least 30)Gaps are years with incomplete station data.

Not what a typical year looks like, but how the typical year has changed. Each stripe is one complete year’s average temperature at the station, 1949 to 2025, colored against the mean of those years: blue for cooler years, red for warmer ones. No trend line is fitted to them: the latest stretch of complete years with no gap over 10 years is 2012–2025, only 11 years (a trend needs at least 30).

Mission Viejo rainfall by month

Mission Viejo averages 10.7 inches of precipitation a year. The wettest month is February and the driest is June.

Mission Viejo temperature records

All-time record high: 116°Fset September 6, 2020
All-time record low: 17°Fset December 21, 1968

Records are drawn from the nearest long-term weather station’s full daily history, so they capture the most extreme single day Mission Viejo has recorded — not a typical seasonal high or low.

Frequently asked

What is the hottest month in Mission Viejo?: August is Mission Viejo's hottest month, with the highest average daily high of the year. The month-by-month table above shows Mission Viejo's exact average high and low for each month, based on the 1991–2020 climate normals — the standard 30-year reference period meteorologists use.
What is the coldest month in Mission Viejo?: December is Mission Viejo's coldest month, with the lowest average daily low of the year. The averages-by-month chart above gives the exact average high and low for every month, so you can see how cold a typical winter day runs.
How much does it rain in Mission Viejo?: Mission Viejo's total annual precipitation and its wettest and driest months are shown in the rainfall-by-month section above. Those figures are 1991–2020 normals — the average monthly precipitation total across that 30-year window — so they reflect a typical year rather than any single wet or dry season.
What months are best to visit Mission Viejo?: The most comfortable months in Mission Viejo are usually the shoulder seasons — spring and fall — when temperatures sit between the summer peak and winter low and rainfall is moderate. Compare the average high, low, and precipitation for each month in the table above to pick the window that fits the weather you want.
Has Mission Viejo gotten hotter?: There isn't enough data to say. The warming-stripes chart above plots Mission Viejo's annual mean temperature for every complete year of station data from 1949 to 2025, but no trend line is fitted: the latest stretch of complete years with no gap over 10 years is 2012–2025, only 11 years (a trend needs at least 30). A shorter or broken record can't separate a climate trend from normal year-to-year swings.
What is the record high temperature in Mission Viejo?: Mission Viejo's all-time record high — the hottest single day in the station record — is shown in the records section above, along with the date it occurred. Records are drawn from the nearest long-term weather station's full daily history, which begins in 1949, so they capture the most extreme heat on record, not just a typical summer day.
What is the record low temperature in Mission Viejo?: Mission Viejo's all-time record low and the date it was set appear in the records section above. Like the record high, it comes from the station's full daily history back to 1949, so it reflects the coldest day on record rather than an average winter low.