| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 39°F | 66°F | 51°F | 4.9" |
| February | 41°F | 71°F | 55°F | 2.3" |
| March | 47°F | 78°F | 62°F | 4.3" |
| April | 53°F | 86°F | 70°F | 1.8" |
| May | 61°F | 94°F | 78°F | 2.3" |
| June | 71°F | 104°F | 89°F | 6.7" |
| July | 80°F | 105°F | 92°F | 6.0" |
| August | 78°F | 103°F | 90°F | 5.5" |
| September | 72°F | 98°F | 85°F | 28.8" |
| October | 58°F | 88°F | 73°F | 1.1" |
| November | 47°F | 76°F | 61°F | 2.4" |
| December | 40°F | 64°F | 51°F | 3.6" |
| Index | San Tan Valley | Arizona | National |
| Air quality index | 74 | 57 | 50 |
| Pollution index | 4,063,380 | 5,576,494 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 36 |
| Days with moderate air quality | 242 |
| Days w/ poor A.Q. for sensitive groups | 60 |
| Days with unhealthy air quality | 19 |
| Pollutant | Total |
| Arsenic | 0.004% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.040% |
| Mercury | 0.001% |
| City, State | Population | Air Quality Index | National Avg. |
| Gilbert, AZ | 226,832 | 74 | 48% |
| Queen Creek, AZ | 30,849 | 74 | 48% |
| Upper Santan Village, AZ | 459 | 74 | 48% |
| Apache Junction, AZ | 37,775 | 74 | 48% |
| Gold Canyon, AZ | 9,616 | 74 | 48% |
| San Tan Valley, AZ | 88,507 | 74 | 48% |
| City, State | Population | Air Quality Index | National Avg. |
| Toms River, NJ | 88,537 | 40 | 20% |
| Edmond, OK | 88,342 | 47 | 6% |
| Newton, MA | 88,317 | 47 | 6% |
| Meridian, ID | 88,247 | 36 | 28% |
| Waukegan, IL | 88,159 | 35 | 30% |
| San Tan Valley, AZ | 88,507 | 74 | 48% |