Weather for Waltham, Massachusetts
Current Weather
Five Day Weather Forecast
Fri
H: 98°F
L: 71°F
Sat
H: 89°F
L: 66°F
Sun
H: 89°F
L: 62°F
Mon
H: 79°F
L: 60°F
Tue
H: 72°F
L: 54°F
Air Quality
Nitrogen Dioxide: 2.8 μg/m3
Sulphur Dioxide: 0.7 μg/m3
Ozone: 135 μg/m3
Astronomical
Sun Transit: 12:44 AM
Sunset: 8:23 PM
Daylight: 15 hrs 16 mins
Moon Transit: 10:08 AM
Moonset: 5:55 PM
Moon Phase: Waning Crescent
Moon Illumination: 2.0%
Best Times for Fishing or Hunting
Major Periods
12:00 AM - 12:00 AM9:38 AM - 12:08 AM
Minor Periods
5:25 PM - 6:55 PM2:06 AM - 3:36 AM
Action Rating: 2 out of 5
Heat Advisory issued June 12 at 2:44AM EDT until June 12 at 8:00PM EDT by NWS Boston/Norton MA
Effective: Fri June 12, 2026, 2:44 AM
Expires: Fri June 12, 2026, 8:00 PM
* WHAT...Heat index values up to 96. * WHERE...Portions of central, eastern, northeastern, and southeastern Massachusetts and northern Rhode Island. * WHEN...Until 8 PM EDT this evening. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.
Air Quality Alert issued June 12 at 2:48AM EDT by NWS Boston/Norton MA
Non-Weather Emergency Message. Not sent to IPAWS.
Effective: Fri June 12, 2026, 2:48 AM
Expires: Fri June 12, 2026, 11:15 PM
The Massachusetts Department of Environmental Protection has issued an Air Quality Alert for Ground Level Ozone, from 11 AM this morning to 11 PM EDT this evening. An Air Quality Alert day means that Ground Level Ozone concentrations within the region may approach or exceed levels that are Unhealthy for Sensitive Groups. Air is unhealthy for sensitive children and adults, such as those with asthma, lung or heart disease, and older adults. Sensitive children and adults should limit prolonged outdoor activity. For additional information, please visit the Massachusetts Department of Environmental Protection website at: https://mass.gov/dep/massair/forecast
Heat Advisory issued June 12 at 2:29AM EDT until June 12 at 8:00PM EDT by NWS Gray ME
Effective: Fri June 12, 2026, 2:29 AM
Expires: Fri June 12, 2026, 8:00 PM
* WHAT...Heat index values of 95 to 100 expected. * WHERE...Portions of southwest and western Maine and central, northern, and southern New Hampshire. * WHEN...From noon today to 8 PM EDT this evening. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
Air Quality Alert issued June 12 at 2:48AM EDT by NWS Boston/Norton MA
Non-Weather Emergency Message. Not sent to IPAWS.
Effective: Fri June 12, 2026, 2:48 AM
Expires: Fri June 12, 2026, 11:15 PM
The Rhode Island Department of Environmental Management has issued an Air Quality Alert Day for Ground Level Ozone, from 11 AM this morning to 11 PM EDT this evening. An Air Quality Alert day means that Ground Level Ozone concentrations within the region may approach or exceed unhealthy standards. For additional information, please visit the Rhode Island Department of Environmental Management website at: https://dem.ri.gov/
Weather Forecast
Air Quality
Nitrogen Dioxide: 13.47 μg/m3
Sulphur Dioxide: 0.97 μg/m3
Ozone: 93.33 μg/m3
Astronomical
Sun Transit: 12:44 AM
Sunset: 8:23 PM
Daylight: 15 hrs 16 mins
Moon Transit: 10:08 AM
Moonset: 5:55 PM
Moon Phase: Waning Crescent
Moon Illumination: 2.0%
Best Times for Fishing or Hunting
Major Periods
12:00 AM - 12:00 AM9:38 AM - 12:08 AM
Minor Periods
5:25 PM - 6:55 PM2:06 AM - 3:36 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.25 μg/m3
Sulphur Dioxide: 0.54 μg/m3
Ozone: 87 μg/m3
Astronomical
Sun Transit: 12:45 AM
Sunset: 8:23 PM
Daylight: 15 hrs 16 mins
Moon Transit: 11:09 AM
Moonset: 7:17 PM
Moon Phase: Waning Crescent
Moon Illumination: 0.1%
Best Times for Fishing or Hunting
Major Periods
12:44 AM - 3:14 AM10:39 AM - 1:09 PM
Minor Periods
6:47 PM - 8:17 PM2:43 AM - 4:13 AM
Action Rating: 3 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.88 μg/m3
Sulphur Dioxide: 0.85 μg/m3
Ozone: 97.21 μg/m3
Astronomical
Sun Transit: 12:45 AM
Sunset: 8:24 PM
Daylight: 15 hrs 17 mins
Moon Transit: 12:15 AM
Moonset: 8:33 PM
Moon Phase: New
Moon Illumination: 0.7%
Best Times for Fishing or Hunting
Major Periods
1:48 AM - 4:18 AM11:45 AM - 2:15 PM
Minor Periods
8:03 PM - 9:33 PM3:33 AM - 5:03 AM
Action Rating: 5 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 4.7 μg/m3
Sulphur Dioxide: 0.57 μg/m3
Ozone: 86.67 μg/m3
Astronomical
Sun Transit: 12:45 AM
Sunset: 8:24 PM
Daylight: 15 hrs 17 mins
Moon Transit: 1:23 PM
Moonset: 9:37 PM
Moon Phase: New
Moon Illumination: 3.8%
Best Times for Fishing or Hunting
Major Periods
2:56 AM - 5:26 AM12:53 AM - 3:23 PM
Minor Periods
9:07 PM - 10:37 PM4:36 AM - 6:06 AM
Action Rating: 4 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 5.92 μg/m3
Sulphur Dioxide: 0.52 μg/m3
Ozone: 45.44 μg/m3
Astronomical
Sun Transit: 12:45 AM
Sunset: 8:25 PM
Daylight: 15 hrs 17 mins
Moon Transit: 2:29 PM
Moonset: 10:27 PM
Moon Phase: New
Moon Illumination: 1.0%
Best Times for Fishing or Hunting
Major Periods
4:03 AM - 6:33 AM1:59 PM - 4:29 PM
Minor Periods
9:57 PM - 11:27 PM5:51 AM - 7:21 AM
Action Rating: 3 out of 5