| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 54f - Valparaiso-Wheaton Morainal Complex |
| Heat Zone Days: | 8 - 14 days Over 86°F |
Annual Climate Data for ZIP Code 60139 - Glendale Heights, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 18 | 28 | 37 | 47 | 57 | 62 | 61 | 53 | 41 | 31 | 20 | 39 |
| Avg Max Temp (°F) | 30 | 36 | 48 | 60 | 72 | 81 | 85 | 83 | 76 | 64 | 48 | 35 | 60 |
| Avg Precip (In.) | 1.75 | 1.51 | 2.53 | 3.75 | 3.8 | 4.07 | 3.93 | 4.49 | 3.4 | 2.64 | 3.11 | 2.34 | 37.32 |