Today | Weather | Saturday, August 29, 2026

Active Weather Warnings

Extreme Heat Warning

Weather in Lake Forest, California

01:54 AM

Now

75° F

Feels Like 77°

Precipitation 0 %

Wind 4 mph

Humidity 78 %

Today

Day 95°

Night 70°

Precipitation 1 %

Wind 7 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.

Lake Forest Weather Forecast Updated

40 minutes ago

Last updated on August 29, 2026 at 1:14 AM

Air Quality in Lake Forest

NOW

93 AQI

Moderate air quality Dominant pollutant: PM_2.5

Pollutant Concentrations:

PM_2.5 32.19 µg/m³

PM₁₀ 50.02 µg/m³

O₃ 0.046 ppm

NO₂ 0.5 ppb

SO₂ 0.2 ppb

CO 0.12 ppm

NH₃ 0.1 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 acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Show raw pollutant concentrations (µg/m³)

PM_2.5 – 32.19 µg/m³

PM₁₀ – 50.02 µg/m³

O₃ – 90.92 µg/m³

NO₂ – 0.93 µg/m³

SO₂ – 0.56 µg/m³

CO – 141.04 µg/m³

NH₃ – 0.1 µg/m³

NO – 0 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Lake Forest

Severe Expected Likely

Extreme Heat Warning

Extreme Heat Warning issued August 28 at 9:06PM PDT until August 29 at 8:00PM PDT by NWS San Diego CA

Aug 28, 9:06 PM → Aug 29, 8:00 PM

WHAT: Hot conditions continue into Saturday with highs up to 95.
Low temperatures will be in the low 70s.

WHERE: Orange County Inland Areas.

WHEN: Until 8 PM PDT Saturday.

IMPACTS: Heat related illnesses increase significantly during
extreme heat events.

ADDITIONAL DETAILS: Temperatures will fall to below normal by
Sunday.

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Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.

Updated: Aug 29, 1:14 AM Source: NWS Alert