Gig Harbor, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.8 °C (low) to 16 °C (high). Annual precipitation averages 1239.8 Millimeters. Gig Harbor is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.2 °C | 8.7 °C | 190.25 mm |
| February | 2.1 °C | 10.1 °C | 111.25 mm |
| March | 3.4 °C | 12.5 °C | 142.24 mm |
| April | 5.3 °C | 15.2 °C | 90.17 mm |
| May | 8.3 °C | 18.8 °C | 53.59 mm |
| June | 10.8 °C | 21.2 °C | 38.61 mm |
| July | 12.8 °C | 24.4 °C | 16.26 mm |
| August | 12.8 °C | 24.7 °C | 25.65 mm |
| September | 10.5 °C | 21.6 °C | 48.77 mm |
| October | 7.1 °C | 15.8 °C | 135.13 mm |
| November | 3.9 °C | 11.2 °C | 188.98 mm |
| December | 2.1 °C | 8.2 °C | 198.88 mm |
| Annual | 6.8 °C | 16 °C | 1239.78 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |