| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 36°F | 26°F | 3.3" |
| February | 17°F | 38°F | 27°F | 4.5" |
| March | 26°F | 47°F | 36°F | 4.7" |
| April | 37°F | 61°F | 49°F | 5.9" |
| May | 47°F | 72°F | 59°F | 5.1" |
| June | 56°F | 79°F | 67°F | 5.9" |
| July | 63°F | 86°F | 74°F | 5.0" |
| August | 60°F | 83°F | 71°F | 5.5" |
| September | 53°F | 76°F | 64°F | 5.7" |
| October | 42°F | 64°F | 52°F | 6.8" |
| November | 31°F | 52°F | 41°F | 5.5" |
| December | 23°F | 41°F | 31°F | 4.8" |
| Index | Hudson | New Hampshire | National |
| Air quality index | 37 | 34 | 42 |
| Pollution index | 6,602,810 | 3,959,618 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 353 |
| Days with moderate air quality | 12 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.060% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Milford, NH | 8,644 | 37 | 26.0% |
| Lowell, MA | 111,311 | 37 | 26.0% |
| Londonderry, NH | 12,053 | 37 | 26.0% |
| Pepperell, MA | 2,685 | 37 | 26.0% |
| Nashua, NH | 89,052 | 37 | 26.0% |
| Hudson, NH | 7,230 | 37 | 26.0% |
| City | Population | Air Quality Index | National Avg. |
| Midland Park, NJ | 7,230 | 51 | 2.0% |
| Wauseon, OH | 7,229 | 39 | 22.0% |
| Otonabee-South Monaghan, ON | 7,229 | n/a | |
| Ridgefield, CT | 7,228 | 43 | 14.0% |
| Stanwood, WA | 7,228 | 24 | 52.0% |
| Hudson, NH | 7,230 | 37 | 26.0% |
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