Today | Weather | Friday, October 9, 2026

Weather in Waltham, Massachusetts

01:42 PM
Now
Rainy Weather
68° F
Feels Like 64°
Precipitation 42 %
Wind 16 mph
UV Index (0 - 11+) 1
Humidity 39 %
Today
Partly Sunny with Showers
Day 70°
Night 45°
Precipitation 49 %
Wind 12 mph
UV Index (0 - 11+) 4

Waltham Weather Forecast Updated

59 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (October 9, 2025)
Sunny Weather

Day

57°

Night

32°

Wind

12 mph

UV Index

40

Precipitation

0 %

Air Quality in Waltham

NOW
47 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 2.96 µg/m³
PM10 3.99 µg/m³
O3 0.051 ppm
NO2 1.1 ppb
SO2 0.5 ppb
CO 0.13 ppm
NH3 0.33 µg/m³
NO 0.37 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.5 – 2.96 µg/m³
PM10 – 3.99 µg/m³
O3 – 99.72 µg/m³
NO2 – 2 µg/m³
SO2 – 1.43 µg/m³
CO – 143.43 µg/m³
NH3 – 0.33 µg/m³
NO – 0.37 µg/m³