Today | Weather | Thursday, December 4, 2025

Active Weather Warnings

Coastal Flood Advisory

Weather in Napa, California

02:05 AM

Now

41° F

Feels Like 37°

Precipitation 0 %

Wind 6 mph

Humidity 67 %

Today

Day 59°

Night 37°

Precipitation 0 %

Wind 6 mph

UV Index (0 - 11+) 2

Napa Weather Forecast Updated

1 minute ago

Last updated on December 04, 2025 at 2:03 AM

Air Quality in Napa

NOW

29 AQI

Good air quality Dominant pollutant: O₃

Pollutant Concentrations:

PM_2.5 3.78 µg/m³

PM₁₀ 8.2 µg/m³

O₃ 0.031 ppm

NO₂ 2.9 ppb

SO₂ 0.4 ppb

CO 0.13 ppm

NH₃ 0.14 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 – 3.78 µg/m³

PM₁₀ – 8.2 µg/m³

O₃ – 60.95 µg/m³

NO₂ – 5.52 µg/m³

SO₂ – 1.14 µg/m³

CO – 148.65 µg/m³

NH₃ – 0.14 µg/m³

NO – 0 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Napa

Minor Expected Likely

Coastal Flood Advisory

Coastal Flood Advisory issued December 3 at 9:39PM PST until December 7 at 3:00PM PST by NWS San Francisco CA

Dec 3, 9:39 PM → Dec 7, 3:00 PM

WHAT: Up to 1.4 ft of inundation above ground level is
possible in low lying areas near shorelines and tidal
waterways.

WHERE: Bayshore locations along the San Francisco Bay and San
Pablo Bay.

WHEN: Until 3 PM PST Sunday.

IMPACTS: Flooding of lots, parks, and roads with only
isolated road closures expected.

ADDITIONAL DETAILS: At the San Francisco tidal gauge high
tide is expected to be 1.2 ft above normal (7.00 ft MLLW) at
9:04 AM Wednesday, 1.4 ft above normal (7.20 ft MLLW) at 9:48
AM Thursday, 1.4 ft above normal (7.23 ft MLLW) at 10:35 AM
Friday, 1.2 ft above normal (7.08 ft MLLW) at 11:25 AM
Saturday, and 0.9 ft above normal (6.75 ft MLLW) at 12:17 PM
Sunday. High tide timing varies up to 90 minutes earlier or
later along the Pacific Coast and throughout the San Francisco
Bay respectively.

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If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property.

Updated: Dec 4, 2:03 AM Source: NWS Alert