| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 37°F | 57°F | 46°F | 6.0" |
| February | 41°F | 61°F | 49°F | 5.2" |
| March | 49°F | 70°F | 58°F | 6.8" |
| April | 56°F | 77°F | 65°F | 9.0" |
| May | 63°F | 83°F | 72°F | 6.4" |
| June | 72°F | 91°F | 81°F | 7.2" |
| July | 75°F | 94°F | 84°F | 8.7" |
| August | 75°F | 95°F | 84°F | 5.1" |
| September | 67°F | 89°F | 77°F | 10.9" |
| October | 57°F | 79°F | 67°F | 13.0" |
| November | 48°F | 68°F | 57°F | 7.8" |
| December | 40°F | 59°F | 48°F | 7.7" |
| Index | Cumby | Texas | National |
| Air quality index | 51 | 52 | 42 |
| Pollution index | 37,723,200 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 181 |
| Days with moderate air quality | 155 |
| Days w/ poor A.Q. for sensitive groups | 28 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.290% |
| Carbon Tetrachloride | 0.220% |
| Lead | 0.230% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Sulphur Springs, TX | 16,573 | 36 | 28.0% |
| Lone Oak, TX | 644 | 51 | 2.0% |
| Neylandville, TX | 175 | 51 | 2.0% |
| Point, TX | 1,123 | 51 | 2.0% |
| Campbell, TX | 963 | 51 | 2.0% |
| Cumby, TX | 836 | 51 | 2.0% |
| City | Population | Air Quality Index | National Avg. |
| Maricopa Colony, AZ | 836 | 74 | 48.0% |
| Tignall, GA | 836 | 44 | 12.0% |
| Garnavillo, IA | 836 | 29 | 42.0% |
| Millersburg, IN | 836 | 37 | 26.0% |
| Spring Valley, KY | 836 | 49 | 2.0% |
| Cumby, TX | 836 | 51 | 2.0% |