Air quality
Air quality in Gilroy today
Updated
Good (US AQI 46) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Sun, Oct 25, 7:00 pm (02:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Gilroy, California, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 46 Good
- PM2.5
- 6.1 µg/m³ 0.4× WHO 24-h guideline
- PM10
- 6.8 µg/m³
- Ozone
- 69 µg/m³
- Dominant pollutant
- ozone sub-index 46
- Best hour tomorrow
- 6:00 am AQI 56
- European AQI
- 26
Air quality in Gilroy right now
Right now the modelled US Air Quality Index for Gilroy, California, United States is 46, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by ozone, whose own sub-index is 46. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.
PM2.5 is 6.1 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 6.8 µg/m³ against a guideline of 45; ozone is 69 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 15 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 142 µg/m³.
Gilroy AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 37 around Sun 11:00 pm to 68 around Mon 4:00 pm, from "Good" at best to "Moderate" at worst.
The following day looks similar, averaging about 55.
| Local time (America/Los_Angeles) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 7:00 pm | 46 | Good | 6.1 | 7 | 69 |
| Sun 10:00 pm | 39 | Good | 15.3 | 16 | 41 |
| Mon 1:00 am | 41 | Good | 25.8 | 27 | 32 |
| Mon 4:00 am | 52 | Moderate | 35.7 | 36 | 40 |
| Mon 7:00 am | 58 | Moderate | 31.9 | 32 | 34 |
| Mon 10:00 am | 64 | Moderate | 20.2 | 22 | 65 |
| Mon 1:00 pm | 66 | Moderate | 7.4 | 10 | 96 |
| Mon 4:00 pm | 68 | Moderate | 7 | 10 | 96 |
| Mon 7:00 pm | 68 | Moderate | 6.4 | 9 | 69 |
| Mon 10:00 pm | 68 | Moderate | 6.5 | 8 | 46 |
| Tue 1:00 am | 65 | Moderate | 8.8 | 12 | 39 |
| Tue 4:00 am | 60 | Moderate | 9.4 | 12 | 45 |
| Tue 7:00 am | 54 | Moderate | 9.2 | 12 | 43 |
| Tue 10:00 am | 47 | Good | 8.4 | 11 | 62 |
| Tue 1:00 pm | 44 | Good | 8.1 | 12 | 87 |
| Tue 4:00 pm | 45 | Good | 9.4 | 14 | 92 |
| Tue 7:00 pm | 47 | Good | 10.3 | 15 | 70 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Gilroy tomorrow
Between 6 am and 9 pm local time, the cleanest air tomorrow is forecast around 6:00 am (AQI 56, Moderate) and the worst around 4:00 pm (AQI 68). That is a swing of 12 points, so a run or walk around 6:00 am is noticeably better.
Gilroy vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 52 (Moderate). Gilroy at 46 is 6 points cleaner than average.
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Gilroy
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| San Jose | 47 km | 55 | Moderate | 13.4 |
| Santa Clara, CA | 52 km | 55 | Moderate | 13.4 |
| Sunnyvale | 58 km | 55 | Moderate | 13.4 |
| Fremont | 71 km | 62 | Moderate | 21.7 |
| Newark, CA | 72 km | 62 | Moderate | 21.7 |
| Union City | 77 km | 62 | Moderate | 21.7 |
| Dublin, CA | 84 km | 62 | Moderate | 21.7 |
| Hayward | 87 km | 62 | Moderate | 21.7 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Gilroy, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Wildfire smoke
PM2.5 is forecast to reach 36 µg/m³ in the next 24 hours while NASA satellites detected 10 fire hotspots within 300 km in the last day (nearest about 37 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.
Advice for sensitive groups
With the AQI at 46, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Gilroy
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.