Today | Weather | Tuesday, April 21, 2026

Active Weather Warnings

Weather in Pittsburgh, Pennsylvania

04:23 AM

Now

32° F

Feels Like 30°

Precipitation 0 %

Wind 5 mph

Humidity 66 %

Today

Day 70°

Night 55°

Precipitation 3 %

Wind 9 mph

UV Index (0 - 11+) 8

Warning: High UV Index Today: 8

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.

Pittsburgh Weather Forecast Updated

16 minutes ago

Last updated on April 21, 2026 at 4:06 AM

Weather Forecast History

Last Year's Weather on This Day (April 21, 2025)

Day

81°

Night

54°

Wind

12 mph

UV Index

Precipitation

90 %

Air Quality in Pittsburgh

NOW

35 AQI

Good air quality Dominant pollutant: O₃

Pollutant Concentrations:

PM_2.5 4.33 µg/m³

PM₁₀ 5.01 µg/m³

O₃ 0.038 ppm

NO₂ 3 ppb

SO₂ 0.7 ppb

CO 0.16 ppm

NH₃ 0.61 µg/m³

NO 0 µg/m³

PM_2.5 – 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)

PM_2.5 – 4.33 µg/m³

PM₁₀ – 5.01 µg/m³

O₃ – 73.88 µg/m³

NO₂ – 5.56 µg/m³

SO₂ – 1.83 µg/m³

CO – 178.25 µg/m³

NH₃ – 0.61 µg/m³

NO – 0 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Pittsburgh

Severe Future Possible

Freeze Watch

Freeze Watch issued April 19 at 7:59PM EDT until April 21 at 9:00AM EDT by NWS Pittsburgh PA

Apr 20, 11:00 PM → Apr 21, 9:00 AM

WHAT: For the Frost Advisory, temperatures as low as 33 will
result in frost formation. For the Freeze Watch, sub-freezing
temperatures as low as 28 possible.

WHERE: Portions of east central Ohio, southwest and western
Pennsylvania, and northern and the northern panhandle of West
Virginia.

WHEN: For the Frost Advisory, from 2 AM to 10 AM EDT Monday. For
the Freeze Watch, from Monday evening through Tuesday morning.

IMPACTS: Frost and freeze conditions could kill crops, other
sensitive vegetation and possibly damage unprotected outdoor
plumbing. Frost could harm sensitive outdoor vegetation. Sensitive
outdoor plants may be killed if left uncovered.

ADDITIONAL DETAILS: With elevated wind and scattered light
precipitation overnight Sunday night, frost development will be
highly localized to areas that are most sheltered from wind.

+ Read More

Take steps now to protect tender plants from the cold.

Updated: Apr 19, 11:10 PM Source: NWS Alert

Moderate Expected Likely

Freeze Warning

Freeze Warning issued April 21 at 1:30AM EDT until April 21 at 9:00AM EDT by NWS Pittsburgh PA

Apr 21, 1:30 AM → Apr 21, 9:00 AM

WHAT: Sub-freezing temperatures from 25 to 30.

WHERE: Portions of east central Ohio, western Pennsylvania, and
northern West Virginia.

WHEN: Until 9 AM EDT this morning.

IMPACTS: Frost and freeze conditions could kill crops and other
sensitive vegetation.