| 2023 Hardiness Zone: | Zone 8a: 10°F to 15°F Zone 7b: 5°F to 10°F |
| 2012 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 7a: 0F to 5F |
| Average First Frost Date: | Nov. 1 - Nov. 10 |
| Average Last Frost Date: | Apr. 1 - Apr. 10 |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate |
| Ecoregion: | 37d - Arkansas Valley Plains |
| Heat Zone Days: | 91 - 120 days Over 86°F |
Annual Climate Data for ZIP Code 74959 - Spiro, OK | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 27 | 32 | 41 | 49 | 58 | 66 | 71 | 69 | 62 | 50 | 40 | 31 | 50 |
| Avg Max Temp (°F) | 49 | 55 | 64 | 73 | 80 | 88 | 93 | 93 | 85 | 75 | 62 | 52 | 73 |
| Avg Precip (In.) | 2.58 | 2.74 | 4.2 | 4.48 | 5.58 | 4.4 | 3.28 | 2.42 | 4.3 | 3.99 | 5.35 | 3.5 | 46.83 |