Air Quality in Waltham, United States

Rain
16.9°C · 96.5% humidity
16.9°
Feels 16.9°
55
Moderate
Unusually sensitive people should consider reducing prolonged outdoor exertion.
5 stations

Nearby Monitoring Stations

AQI Forecast Calibrated
63 3pm
63
63
55 6pm
57
59
60 9pm
54
54
53 12am
53
52
53 3am
53
53
53 6am
53
53
53 9am
53
53
53 12pm
54
54
Station readings
65
71
56
CAMS model adj +29
34
34
34
34
34
34
34
27
27
25
25
24
24
24
24
24
24
24
24
24
24
24
25
25
AD 728×90

Air Quality Index Trend

47h · 1 stn

Waltham's air quality is primarily affected by vehicle emissions and industrial activity. Seasonal wildfire smoke and weather patterns can cause periodic air quality deterioration.

96.5%
Humidity
76.4 km/h
Wind NNE
1012.7 hPa
Pressure
2.2
UV Moderate
GoodModerateUSGUnhealthyVery UnhealthyHazardous

Which pollutant is driving the AQI?

PM2.5▲
55
14.15 µg/m³
PM10
25
27.45 µg/m³
050100150200300500

What is the weather forecast for Waltham?

Temperature & Precipitation

PM2.5 Trend

47h · 1 station
PM2.514.15 µg/m³ ✓ WHO
Moderate
PM1027.45 µg/m³
Good
UV INDEX2.2
Moderate
AD 300×250
Station readings (5 stations within 25 km)
14.15
Median
12.75
Average
9.6
Low
18.24
High
PM2.5 µg/m³ · Model: 13.7 · Bias: -0.4

What is the 7-day forecast for Waltham?

07-21
27.2° 18.8°
4.19 mm
07-22
22.7° 14.9°
9.25 mm
07-23
27.7° 16.7°
1.81 mm
07-24
26.5° 14.9°
2.31 mm
07-25
35.5° 20.6°
2.88 mm
07-26
23.5° 17.0°
1.63 mm
07-27
28.8° 14.9°
5.94 mm
Both models agree Avg diff: 3.4°C

Where are air quality stations near Waltham?

56
Magazine Beach Park
10.1 km PM2.5: 14.4 µg/m³ PM10: 15.7 µg/m³
53
Nubian Square - DEP Station
13.6 km PM2.5: 13.1 µg/m³
9
Boston Roxbury
13.6 km PM2.5: 2.2 µg/m³
52
Boston
14.6 km PM2.5: 12.6 µg/m³
42
Boston
14.6 km PM2.5: 10.1 µg/m³
32
Milton Blue Hill Observatory
20.9 km PM2.5: 7.7 µg/m³

What cities are near Waltham?

57 Watertown 56 Belmont 58 Brighton 56 Chestnut Hill 63 Allston 55 Wellesley 55 Needham 56 Brookline 59 Cambridge 57 Somerville
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Data sources: AQI from ground-level monitoring stations via AQICN. Weather forecast from ECMWF (IFS & CAMS models). AQI calculated using US EPA standard. Updated 2026-07-21T22:17 UTC.