Rillito, Arizona has a Hot Semi-Arid Climate climate (Köppen classification: BSh). Average annual temperatures range from 13.1 °C (low) to 29.4 °C (high). Annual precipitation averages 279.4 Millimeters. Rillito is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.7 °C | 19.3 °C | 26.42 mm |
| February | 5.2 °C | 20.9 °C | 23.11 mm |
| March | 7.8 °C | 24.8 °C | 16.26 mm |
| April | 10.6 °C | 28.6 °C | 9.65 mm |
| May | 15.3 °C | 33.7 °C | 8.64 mm |
| June | 20.6 °C | 39 °C | 4.83 mm |
| July | 24.4 °C | 39 °C | 45.97 mm |
| August | 23.9 °C | 37.8 °C | 55.37 mm |
| September | 20.8 °C | 35.9 °C | 30.73 mm |
| October | 14 °C | 31.1 °C | 19.3 mm |
| November | 7.6 °C | 24.5 °C | 14.48 mm |
| December | 3.3 °C | 18.7 °C | 24.64 mm |
| Annual | 13.1 °C | 29.4 °C | 279.4 mm |
| Average First Frost Date | Jan. 21 - Jan. 31 |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSh - Hot Semi-Arid Climate |