San Marcos pollen forecast — San Marcos HS's Baseball Diamond neighborhood

On 9 August 2026, overall pollen levels in San Marcos are moderate. Artemisia is the main contributor to airborne pollen, while ambrosia, cypress, and grass remain at lower levels

On 10 August 2026, pollen conditions in San Marcos will be different from today, with artemisia at medium levels, grass at low levels, ambrosia at medium levels

According to the five-day outlook, artemisia, cypress, grass, and ambrosia pollen levels will increase later in the week.

On 9 August 2026, Artemisia is the dominant pollen source in San Marcos. ambrosia, cypress, and grass are also present but at lower levels.

As a baseball venue within San Marcos, San Marcos HS's Baseball Diamond follows the same seasonal pollen curve, opening with olive and acacia from January then eucalyptus follows, running through February. Grass pollen rises through March and April, and light weed pollen carries into September. Onshore Pacific breezes periodically clear the air, though inland valleys can still see elevated counts, which shapes conditions at San Marcos HS's Baseball Diamond much as it does elsewhere in San Marcos.

The San Marcos pollen forecast is updated four times daily. See the timestamp below for the most recent update.

Studies show that most pollen exposure (often 70–90%) comes from nearby sources, such as local trees and vegetation. A good pollen forecast therefore depends on accurately representing local vegetation. Pollen can travel long distances, but this usually matters only early in the season or during specific wind events.

Pollen data is often misunderstood. Most "pollen levels" are not real-time measurements, but forecasts.

Direct pollen measurements are typically delayed by 1-2 days because they require manual analysis. To show current conditions in San Marcos, modern forecasts combine recent measurements, weather data, and information about local vegetation.

This allows us to estimate pollen levels for today and the coming days, not just report the past.

Airmine’s atmospheric monitoring platform was developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team, using satellite and Earth observation technologies to improve emissions monitoring.