Today | Weather | Friday, September 18, 2026

Weather in Sammamish, Washington

05:34 AM
Now
Cloudy Night
52° F
Feels Like 50°
Precipitation 0 %
Wind 5 mph
Humidity 92 %
Today
Cloudy Weather
Day 73°
Night 50°
Precipitation 1 %
Wind 5 mph
UV Index (0 - 11+) 4

Sammamish Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 18, 2025)
Sunny Weather

Day

72°

Night

50°

Wind

6 mph

UV Index

40

Precipitation

1 %

Air Quality in Sammamish

NOW
29 AQI
Good air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 6.86 µg/m³
PM10 9.41 µg/m³
O3 0.015 ppm
NO2 1.5 ppb
SO2 0.1 ppb
CO 0.13 ppm
NH3 0.68 µg/m³
NO 0 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)
PM2.56.86 µg/m³
PM109.41 µg/m³
O330.29 µg/m³
NO22.88 µg/m³
SO20.39 µg/m³
CO154.04 µg/m³
NH30.68 µg/m³
NO0 µg/m³