| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Nov. 1 - Nov. 10 |
| Average Last Frost Date: | Apr. 1 - Apr. 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 72e - Middle Mississippi Alluvial Plain |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 62040 - Granite City, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 20 | 25 | 35 | 45 | 55 | 65 | 69 | 67 | 59 | 47 | 36 | 26 | 46 |
| Avg Max Temp (°F) | 38 | 44 | 55 | 66 | 76 | 85 | 90 | 88 | 80 | 69 | 54 | 42 | 66 |
| Avg Precip (In.) | 2.08 | 2.23 | 3.53 | 3.94 | 4.18 | 3.71 | 3.73 | 3.22 | 3.12 | 2.81 | 3.78 | 2.93 | 39.25 |