| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 20.1° | 9.9° | — | — | 94 |
| February | 19.7° | 9.1° | — | — | 93 |
| March | 20.6° | 9.4° | — | — | 94 |
| April | 21.8° | 10.2° | — | — | 94 |
| May | 23° | 12° | — | — | 94 |
| June | 25.7° | 13.7° | — | — | 94 |
| July | 29.3° | 15.9° | — | — | 85 |
| August | 30.6° | 16.5° | — | — | 80 |
| September | 29.9° | 16.3° | — | — | 82 |
| October | 26.7° | 14.5° | — | — | 94 |
| November | 23.4° | 12° | — | — | 94 |
| December | 19.7° | 9.7° | — | — | 93 |
January in Mission Viejo averages a daily high of 20.1°C with nights around 9.9°C. Comfortable conditions for being outdoors all day.
February in Mission Viejo averages a daily high of 19.7°C with nights around 9.1°C. Comfortable conditions for being outdoors all day.
March in Mission Viejo averages a daily high of 20.6°C with nights around 9.4°C. Comfortable conditions for being outdoors all day.
April in Mission Viejo averages a daily high of 21.8°C with nights around 10.2°C. Comfortable conditions for being outdoors all day.
May in Mission Viejo averages a daily high of 23°C with nights around 12°C. Comfortable conditions for being outdoors all day.
June in Mission Viejo averages a daily high of 25.7°C with nights around 13.7°C. Comfortable conditions for being outdoors all day.
July in Mission Viejo averages a daily high of 29.3°C with nights around 15.9°C. Comfortable conditions for being outdoors all day.
August in Mission Viejo averages a daily high of 30.6°C with nights around 16.5°C. Comfortable conditions for being outdoors all day.
September in Mission Viejo averages a daily high of 29.9°C with nights around 16.3°C. Comfortable conditions for being outdoors all day.
October in Mission Viejo averages a daily high of 26.7°C with nights around 14.5°C. Comfortable conditions for being outdoors all day.
November in Mission Viejo averages a daily high of 23.4°C with nights around 12°C. Comfortable conditions for being outdoors all day.
December in Mission Viejo averages a daily high of 19.7°C with nights around 9.7°C. Comfortable conditions for being outdoors all day.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Mission Viejo peaks at 94.
Based on 30 years of records, October–June scores highest for comfort in Mission Viejo, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.6°C.
January is the wettest, averaging —mm of rain across roughly — wet days.
February is the coolest month, with average daily highs around 19.7°C.