Air quality in San Clemente, California, United States of America today

Mr. Duck’s Air Quality Score

Good air today for San Clemente, Emilia-Romagna, Italy

⚠️ This website is currently under active development. Some data may be incomplete or temporarily inaccurate. For health-critical decisions, please verify information through official government or environmental sources.

Categories follow US EPA AQI breakpoints for PM (estimate from latest valid measurements; this project does not compute EPA NowCast/24-hour AQI yet).

This friendly indicator summarizes the latest city readings. For health guidance, please see: EPA AirNow or WHO.

Air quality today

The air quality in San Clemente today is classified as Good. The primary pollutant identified is PM2.5 (fine particles).

Measurements show a PM2.5 concentration of 0.009041666922469934 micrograms per cubic meter, based on twelve valid observations reported through OpenAQ. No PM10 value is available for this assessment. This page is informational; for health guidance, use official sources such as EPA AirNow or WHO.

Latest sensor values

PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).

What the data includes

The dataset for San Clemente pulls in six measured pollutants – PM1, PM2.5, PM10, relative humidity, temperature and UM003 (particle count). In total there are eleven recent‑time rows (rt=11) drawn from two distinct monitoring stations (st=2). The newest observations across the board were recorded on 2026‑02‑11 at 01:00 UTC for five of the pollutants; PM10 is an outlier, with its only entry dated 2025‑01‑13 at 23:00 UTC and coming from a different source (Reisfelt Manor LTD). All other variables are flagged as “Updated within 30 days,” indicating that the most current data are less than a month old.

PM1 values range from zero to about 4.42 µg/m³, with a median of roughly 2.21 µg/m³ and the central 80 % falling between 0.44 and 3.98 µg/m³. PM2.5 shows a broader spread: minimum just above zero (0.009 µg/m³), maximum 7.58 µg/m³, median near 3.80 µg/m³ and the 10th‑90th percentile band from 0.77 to 6.83 µg/m³. Relative humidity stays within a narrow window of roughly 56 % to 62 %, centering on 59 %. Temperature is similarly tight, varying between about 17.71 °C and 18.69 °C with a median of 18.20 °C. The UM003 particle count exhibits the widest variability, from a low of 85.75 particles/cm³ up to 1 010 particles/cm³; half of the observations sit near 548 particles/cm³, while the bulk (10th‑90th percentile) lies between 178 and 918 particles/cm³.

Because PM10 is represented by only one older record, its coverage is sparse compared with the other five pollutants that benefit from multiple recent rows. The overall picture shows fairly fresh data for most metrics but highlights an uneven temporal depth: while temperature, humidity and fine‑particle measures are regularly refreshed, coarse‑particle (PM10) information lags behind, meaning city‑wide condition snapshots may differ by location and time depending on which sensor is consulted.

Learn more about sources and filtering: About the data.

Trusted references: WHO (Air pollution) · US EPA AirNow · European Environment Agency (Air)

Latest sensor values (bars)

PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).

Data notes

The data shown reflects twelve valid measurements and was updated today (2026‑02‑11T01:00:00+00:00). While this snapshot provides a current view of air quality in San Clemente, conditions can differ across neighborhoods and change throughout the day, so local variations may not be captured by these aggregate values.

OpenAQ station rows