Today | Weather | Wednesday, May 20, 2026
Active Weather Warnings

Weather in Pasadena, California

01:54 PM
Now
Sunny Weather
88° F
Feels Like 93°
Precipitation 0 %
Wind 9 mph
UV Index (0 - 11+) 10
Humidity 17 %
Today
Sunny Weather
Day 88°
Night 61°
Precipitation 1 %
Wind 7 mph
UV Index (0 - 11+) 11

Warning: Extreme UV Index Today: 11

Overexposure to the sun's harmful UV rays can cause sunburn and increase the risk of developing skin cancer, including melanoma. Protect yourself by wearing clothing that covers your skin, sunglasses, and a hat. Apply a broad-spectrum sunscreen with an SPF of 30 or higher every two hours, even on cloudy days. Minimize direct sun exposure during peak hours (10 AM to 4 PM) to reduce the risk.

Pasadena Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (May 20, 2025)
Sunny Weather

Day

86°

Night

64°

Wind

6 mph

UV Index

11

Precipitation

0 %

Air Quality in Pasadena

NOW
48 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 9.97 µg/m³
PM10 22.41 µg/m³
O3 0.052 ppm
NO2 0.2 ppb
SO2 0.3 ppb
CO 0.11 ppm
NH3 0 µg/m³
NO 0.06 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)
PM2.59.97 µg/m³
PM1022.41 µg/m³
O3101.56 µg/m³
NO20.3 µg/m³
SO20.66 µg/m³
CO127.54 µg/m³
NH30 µg/m³
NO0.06 µg/m³

Weather Alerts and Warnings for Pasadena

Air Quality Alert

Air Quality Alert issued May 19 at 9:43PM PDT by NWS Los Angeles/Oxnard CA
May 19, 9:43 PM May 20, 5:30 PM
WHAT: The South Coast AQMD has issued an air quality alert due to
increased fine particle pollution from wildfire smoke. Visit
https://www.aqmd.gov/alertinfo to check current and forecasted air
quality levels.

WHERE: in portions of Los Angeles County. Levels of particle
pollution can vary by time and location depending on fire activity
and local weather conditions.

WHEN: until Wednesday at 4:30 PM.

IMPACTS: Particles in wildfire smoke can get deep into the lungs
and cause serious health problems such as heart attacks, strokes,
asthma attacks, and difficulty breathing. Everyone can be affected,
but people with lung or heart disease, older adults, people who
are pregnant, children, and those who spend a lot of time outdoors
are at greater risk.
+ Read More
To protect your health, if you smell or see smoke: * Remain indoors with windows and doors closed * Avoid intense outdoor physical activity * Run your air conditioner and/or an air purifier * If you must be outdoors, keep the time brief and wear a well- fitting N-95 mask * Do not use whole house fans or swamp coolers that bring in outside air if you have other methods to stay cool * Avoid other sources of pollution such as fireplaces, candles, incense, grilling, and gasoline-powered lawn and garden equipment
Updated: May 20, 12:39 PM Source: NWS Alert