Today | Weather | Tuesday, July 21, 2026
Active Weather Warnings

Weather in Hillsboro, Oregon

03:15 AM
Now
Cloudy Night
64° F
Feels Like 66°
Precipitation 7 %
Wind 2 mph
Humidity 88 %
Today
Hot Day
Day 99°
Night 64°
Precipitation 0 %
Wind 5 mph
UV Index (0 - 11+) 9

Warning: High UV Index Today: 9

High risk of harm from unprotected sun exposure. Take precautions: wear a hat, sunglasses, and apply sunscreen regularly if you’ll be outdoors for extended periods.

Hillsboro Weather Forecast Updated

39 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (July 21, 2025)
Night

Day

81°

Night

54°

Wind

5 mph

Precipitation

9 %

Air Quality in Hillsboro

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

Pollutant Concentrations:

PM2.5 6.67 µg/m³
PM10 9.7 µg/m³
O3 0.008 ppm
NO2 1.2 ppb
SO2 0.1 ppb
CO 0.08 ppm
NH3 0.59 µg/m³
NO 0.01 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)
PM2.56.67 µg/m³
PM109.7 µg/m³
O316.65 µg/m³
NO22.22 µg/m³
SO20.14 µg/m³
CO93.7 µg/m³
NH30.59 µg/m³
NO0.01 µg/m³

Weather Alerts and Warnings for Hillsboro

Moderate Expected Likely

Heat Advisory

Heat Advisory issued July 20 at 9:01PM PDT until July 22 at 11:00PM PDT by NWS Portland OR
Jul 21, 10:00 AM Jul 22, 11:00 PM
WHAT: Temperatures as high as 95 to 100 expected.

WHERE: Western and Central Columbia River Gorge and the Hood
River Valley, Portland Metro Lowlands, Greater Vancouver Metro,
Lower Columbia River and Cowlitz River Valleys, and East Central
Willamette Valley.

WHEN: From 10 AM Tuesday to 11 PM PDT Wednesday.

IMPACTS: Hot temperatures may cause heat illnesses.

ADDITIONAL DETAILS: Smoke from fires outside of the region or
clouds moving into the area could result in cooler daytime high
temperatures than currently forecast.
+ Read More
Drink plenty of fluids, stay in a cool place during the heat of the day, stay out of the sunshine, and check up on relatives and neighbors. For those without air conditioning, use fans to keep air moving. Keeps windows closed during the day and open at night, unless air quality is degraded due to wildfire smoke. 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. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.
Updated: Jul 21, 2:35 AM Source: NWS Alert