| Climate data for San Clemente Island, CA (normals and extremes 1963-1989) |
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 84.0(28.9) | 80.1(26.7) | 87.1(30.6) | 88.0(31.1) | 93.9(34.4) | 100.9(38.3) | 86.0(30.0) | 84.9(29.4) | 102.0(38.9) | 93.9(34.4) | 90.0(32.2) | 79.0(26.1) | 102.0(38.9) |
| Mean daily maximum °F (°C) | 65(18) | 64(18) | 65(18) | 68(20) | 69(21) | 71(22) | 74(23) | 75(24) | 75(24) | 73(23) | 68(20) | 65(18) | 69(21) |
| Mean daily minimum °F (°C) | 49(9) | 50(10) | 52(11) | 54(12) | 57(14) | 60(16) | 62(17) | 64(18) | 63(17) | 59(15) | 53(12) | 49(9) | 56(13) |
| Record low °F (°C) | 36.0(2.2) | 39.9(4.4) | 39.0(3.9) | 42.1(5.6) | 44.1(6.7) | 52.0(11.1) | 52.0(11.1) | 55.0(12.8) | 52.0(11.1) | 44.1(6.7) | 41.0(5.0) | 37.9(3.3) | 36.0(2.2) |
| Average precipitation days (≥ 1.0 mm (0.039 inches)) | 4.7 | 3.8 | 4.3 | 2.4 | 0.6 | 0.1 | 0.2 | 0.2 | 0.8 | 0.9 | 3.2 | 3.6 | 24.8 |
| Average relative humidity (%) (at 10 PT) | 71.4 | 74.1 | 73 | 68.9 | 71.9 | 74.1 | 75.9 | 74.9 | 74.5 | 71.9 | 71.4 | 72.7 | 72.9 |
| Average dew point °F (°C) | 47.7(8.7) | 49.3(9.6) | 49.5(9.7) | 49.5(9.7) | 51.8(11.0) | 55.0(12.8) | 57.9(14.4) | 59.5(15.3) | 58.8(14.9) | 56.1(13.4) | 52.3(11.3) | 49.3(9.6) | 53.1(11.7) |
| Source 1: NOAA (all data except mean daily max/min) |
| Source 2: Weather .mw- .mw- .mw- body:not(.skin-timeless):not(.skin-minerva) id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw- .mw- .mw- .mw- } }"Monthly weather". San Clemente Island, CA. 2016. Retrieved September 12, 2016. |
