| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 21.1° | 8.6° | 63.9mm | 4.3 | 91 |
| February | 21.5° | 8.1° | 67.2mm | 4.2 | 92 |
| March | 23.2° | 9.1° | 37.1mm | 3.8 | 92 |
| April | 24.8° | 10.2° | 18.1mm | 2 | 96 |
| May | 25.5° | 12.5° | 10mm | 1.6 | 97 |
| June | 28° | 14.3° | 1.1mm | 0.4 | 95 |
| July | 31.3° | 16.4° | 1.8mm | 0.2 | 82 |
| August | 32.2° | 16.6° | 3.1mm | 0.2 | 79 |
| September | 31.3° | 15.9° | 3.7mm | 0.5 | 82 |
| October | 28.2° | 13.8° | 19.2mm | 2 | 91 |
| November | 24.4° | 10.9° | 22.6mm | 2.2 | 96 |
| December | 20.3° | 8.5° | 64.4mm | 4.2 | 92 |
January in Lake Forest averages a daily high of 21.1°C with nights around 8.6°C. Expect roughly 4.3 wet days totalling 63.9mm. Comfortable conditions for being outdoors all day.
February in Lake Forest averages a daily high of 21.5°C with nights around 8.1°C. Expect roughly 4.2 wet days totalling 67.2mm. Comfortable conditions for being outdoors all day.
March in Lake Forest averages a daily high of 23.2°C with nights around 9.1°C. Expect roughly 3.8 wet days totalling 37.1mm. Comfortable conditions for being outdoors all day.
April in Lake Forest averages a daily high of 24.8°C with nights around 10.2°C. Rain is rare — about 2 wet days and 18.1mm across the month. Comfortable conditions for being outdoors all day.
May in Lake Forest averages a daily high of 25.5°C with nights around 12.5°C. Rain is rare — about 1.6 wet days and 10mm across the month. Comfortable conditions for being outdoors all day.
June in Lake Forest averages a daily high of 28°C with nights around 14.3°C. Rain is rare — about 0.4 wet days and 1.1mm across the month. Comfortable conditions for being outdoors all day.
July in Lake Forest averages a daily high of 31.3°C with nights around 16.4°C. Rain is rare — about 0.2 wet days and 1.8mm across the month. Comfortable conditions for being outdoors all day.
August in Lake Forest averages a daily high of 32.2°C with nights around 16.6°C. Rain is rare — about 0.2 wet days and 3.1mm across the month. Comfortable conditions for being outdoors all day.
September in Lake Forest averages a daily high of 31.3°C with nights around 15.9°C. Rain is rare — about 0.5 wet days and 3.7mm across the month. Comfortable conditions for being outdoors all day.
October in Lake Forest averages a daily high of 28.2°C with nights around 13.8°C. Rain is rare — about 2 wet days and 19.2mm across the month. Comfortable conditions for being outdoors all day.
November in Lake Forest averages a daily high of 24.4°C with nights around 10.9°C. Rain is rare — about 2.2 wet days and 22.6mm across the month. Comfortable conditions for being outdoors all day.
December in Lake Forest averages a daily high of 20.3°C with nights around 8.5°C. Expect roughly 4.2 wet days totalling 64.4mm. 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. Lake Forest peaks at 97.
Based on 30 years of records, October–June scores highest for comfort in Lake Forest, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 32.2°C.
February is the wettest, averaging 67.2mm of rain across roughly 4.2 wet days.
December is the coolest month, with average daily highs around 20.3°C.