| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate |
| Ecoregion: | 10e - Pleistocene Lake Basins |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 98944 - Sunnyside, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 25 | 29 | 34 | 39 | 46 | 52 | 56 | 55 | 47 | 38 | 31 | 25 | 40 |
| Avg Max Temp (°F) | 40 | 47 | 58 | 66 | 74 | 81 | 89 | 89 | 79 | 67 | 50 | 40 | 65 |
| Avg Precip (In.) | .89 | .61 | .63 | .52 | .56 | .43 | .19 | .31 | .46 | .53 | .98 | 1.16 | 7.26 |