Air Quality in California

Air Quality Outlook

California's air quality today is Good, with an AQI of 17.

AQI condition is currently Good with little or no pollution risk. Normal outdoor activities are suitable for most people

However, conditions may change throughout the day. Check the hourly air quality forecast to see when air quality may affect your health.

Air Quality Forecast for the Next 24 Hours in California

The Air Quality Forecast for the Next 24 Hours shows how air quality in California is expected to change from hour to hour.

The forecast starts at around 17, with conditions classified as Good, before gradually changing throughout the day.

Checking this hourly trend can help you understand when air quality is expected to be more favorable or less favorable for outdoor activities.

During the early morning, the forecast shows relatively stable air quality, with AQI values remaining around the lower range.

As the morning progresses, the AQI gradually increases, reaching approximately around the middle of the morning.

Conditions remain relatively steady around this period, although small fluctuations may occur from hour to hour.

Around midday, the forecast indicates a slight change in AQI before levels begin rising again during the afternoon.

By the evening, the increase becomes more noticeable, with the AQI reaching around  and conditions classified as 

This suggests that air quality may become less favorable later in the day compared with the earlier hours.

The hourly forecast is useful when planning outdoor activities such as walking, running, cycling, or other exercise.

If the AQI is lower during certain hours, you may prefer to schedule longer outdoor activities during those periods.

When the AQI reaches a higher level or is classified as Unhealthy, consider reducing prolonged outdoor exposure, particularly if you are sensitive to air pollution.

Air quality can change throughout the day, so relying on a single AQI reading may not provide the full picture.

Reviewing the next 24 hours of air quality gives you a clearer view of the expected trend and helps you plan around periods when conditions may be less favorable.

Check the latest Air Quality Forecast for California to monitor AQI, understand the current AQI classification, and choose the best time for your outdoor plans.

Daily AQI Forecast in California

Checking the Daily AQI Forecast in California is an important part of planning a healthy and comfortable day outdoors.

Unlike temperature, air quality can change significantly from one day to another—and even from one hour to the next.

California’s large cities, inland valleys, coastal communities, mountains, and desert areas can experience very different air-quality conditions because of weather, traffic, ozone, particle pollution, and wildfire smoke.

The Air Quality Index (AQI) converts pollution levels into an easy-to-understand number and category. The U.S. AQI ranges from 0 to 500, with lower values indicating better air quality.

Categories include Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous.

Why Should You Check the Daily AQI Forecast?

The biggest benefit of checking AQI is that it helps you make better decisions before spending time outdoors. An AQI forecast can indicate whether it is a good day for running, cycling, hiking, walking, sports, outdoor work, or family activities.

For example, if the forecast shows AQI: 42 and AQILEVEL: Good, you can use that information to decide whether to continue with your plans, reduce strenuous activity, choose a cleaner location, or move activities indoors.

EPA specifically recommends using AQI forecasts to plan outdoor activities and reduce exposure when pollution is expected to be elevated.

Checking AQI can also be particularly useful during wildfire smoke events. Smoke can cause particle pollution to rise quickly, meaning conditions may become less favorable even when the weather looks pleasant.

California air-quality agencies recommend checking air-quality information frequently because hourly conditions can change.

Benefits of Checking AQI Every Day
1. Plan outdoor activities smarter

Check the forecast before exercising, hiking, commuting, or organizing outdoor events.

If pollution is expected to be higher, consider moving strenuous activities to a cleaner period of the day.
2. Reduce exposure to pollution

AQI information helps you adjust the intensity and duration of outdoor activity.

For example, walking instead of running or spending less time outside can reduce the amount of polluted air you inhale.
3. Protect sensitive groups

Children, older adults, and people who are particularly sensitive to air pollution may need to take additional precautions when AQI levels rise.

California guidance recommends adjusting outdoor activity according to the AQI category.
4. Prepare for wildfire smoke

During wildfire periods, checking AQI regularly can help you identify worsening conditions earlier and decide when to limit outdoor exposure.
5. Choose the best time of day

Air quality does not necessarily remain constant throughout the day.

Some areas provide hourly forecasts or identify cleaner periods, allowing you to schedule outdoor activities when conditions are more favorable.

Tips and Tricks for Using the AQI Forecast
A simple habit is to check AQI before checking your outdoor schedule.

• Start with the daily AQI and AQILEVEL, then look at the expected trend during the day.
• Compare AQI with the current reading: A forecast is an estimate, while current AQI can change during the day.
• Check more frequently during wildfire events: Smoke conditions can change rapidly.
• Look beyond the number: Pay attention to the AQI category and primary pollutant, not just the numerical value.
• Check your specific location: California is geographically diverse, so statewide conditions may not represent the air quality in your city.
• Plan strenuous exercise carefully: If AQI is elevated, reduce exercise intensity, shorten the duration, or move the activity indoors.
• Recheck before heading outside: Conditions can change even when the morning forecast looked favorable.

Ultimately, the Daily AQI Forecast in California is more than a pollution number—it is a practical planning tool.

By checking AQI, AQILEVEL, current conditions, and daily trends, you can make more informed decisions about outdoor activities and reduce unnecessary exposure to poor air quality.

Frequently asked questions

1. What is the AQI in California today?

Today’s AQI in California is 17, classified as Good.

2. Is the AQI in California good today?

The current AQI is 17, with an air-quality level of Good.

3. Why does AQI vary across California?

AQI varies because of differences in weather, geography, traffic, emissions, and wildfire smoke.

4. Is it safe to exercise outdoors in California today?

With an AQI of 17 and a level of Good, check the AQI category before planning prolonged or strenuous outdoor activity.

5. What AQI level is unhealthy?

An AQI of 151–200 is classified as Unhealthy, while higher levels indicate greater health risks.

6. Will California’s AQI change during the day?

Yes. AQI can change as pollution and weather conditions change. The current AQI may therefore differ from the daily forecast.

7. Does wildfire smoke affect AQI in California?

Yes. Wildfire smoke can significantly increase AQI, particularly because smoke contains fine particulate matter such as PM2.5.

These tiny particles can penetrate deep into the lungs, making AQI especially important to monitor during wildfire events. California Air Resources Board recommends checking reliable AQI information and smoke forecasts when wildfire smoke is present.