Oak Glen, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 45.4 °F (low) to 68.8 °F (high). Annual precipitation averages 24.5 Inches. Oak Glen is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.1 °F | 55.1 °F | 5.03 in. |
| February | 34.7 °F | 55.0 °F | 6.24 in. |
| March | 37.1 °F | 59.6 °F | 4.17 in. |
| April | 39.5 °F | 63.7 °F | 1.68 in. |
| May | 45.1 °F | 70.8 °F | 0.76 in. |
| June | 52.8 °F | 79.5 °F | 0.17 in. |
| July | 60.8 °F | 85.8 °F | 0.26 in. |
| August | 61.0 °F | 86.2 °F | 0.15 in. |
| September | 56.1 °F | 81.8 °F | 0.45 in. |
| October | 47.6 °F | 71.4 °F | 0.81 in. |
| November | 40.2 °F | 62.3 °F | 1.5 in. |
| December | 34.6 °F | 54.4 °F | 3.26 in. |
| Annual | 45.4 °F | 68.8 °F | 24.48 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |