San Luis pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in San Luis is moderate; ragweed is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week mugwort will increase; ragweed will decrease; grass will remain stable.
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Features and forecast availability vary by region.
Pollen Risk
Today - 20 September
| Pollen species | Level | Value |
|---|---|---|
| Alder (Alnus) | None | 0/100 |
| Birch (Betula) | None | 0/100 |
| Hazel (Corylus) | None | 0/100 |
| Cypress (Cupressaceae) | None | 0/100 |
| Grass (Poaceae) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 6/100 |
| Ragweed (Ambrosia) | Moderate | 44/100 |
Tomorrow - 21 September
| Pollen species | Level | Value | 7-Day Trend |
|---|---|---|---|
| Alder (Alnus) | None | 0/100 | — |
| Birch (Betula) | None | 0/100 | — |
| Hazel (Corylus) | None | 0/100 | — |
| Cypress (Cupressaceae) | None | 0/100 | — |
| Grass (Poaceae) | None | 0/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 8/100 | |
| Ragweed (Ambrosia) | Moderate | 46/100 |
Local Environmental Conditions
Aspen and willow thrive along the cold mountain bank, both common subalpine streamside trees; this sits nearby. Parkland with regularly mown grass and planted trees, both sources of grass and ragweed pollen; this sits within the neighborhood. Surrounding neighborhoods with similar tree cover typically see a closely comparable pollen mix.
January is the coldest month here at around -5°C, warming to about 21°C by July, and most of the 401 mm annual rainfall falls in the warmer months around July. Expect pollen activity to start building from around February, tracking the rise in temperature out of the January low.
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Frequently Asked Questions About Pollen in Colorado
Is pollen high in San Luis right now?
On 20 September 2026, overall pollen levels in San Luis are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia remain at lower levels
Will pollen levels change in San Luis tomorrow?
On 21 September 2026, pollen conditions in San Luis will be similar to today, with ambrosia at moderate levels, artemisia at low levels
Is pollen expected to decrease in San Luis this week?
According to the five-day outlook, ambrosia pollen levels are expected to gradually decrease, while artemisia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in San Luis?
On 20 September 2026, Ambrosia is the dominant pollen source in San Luis. artemisia are also present but at lower levels. grass are not currently active.
When is pollen season in San Luis?
How often is the San Luis pollen forecast updated?
The San Luis pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in San Luis come from nearby or far away?
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.
Are pollen levels in San Luis based on measurements or forecasts?
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 Luis, 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.
Understanding the Scale
The 0–100 scores represent risk levels, not direct measurements of pollen or air pollutant concentrations. Higher scores indicate higher risk. Pollen and air quality use different thresholds.
Pollen
| None | 0 | No or negligible risk of exposure. Pollen/mold exposure is expected to be minimal. |
| Low | 0-25 | Low risk of exposure. Small amounts of pollen or mold spores may be present. |
| Moderate | 25-50 | Moderate risk of exposure. Pollen/mold exposure is expected to be noticeable. |
| High | 50-75 | High risk of exposure. Elevated pollen/mold exposure is expected. |
| Very High | 75-100 | Very high risk of exposure. Pollen/mold exposure is expected to be at or near its highest levels. |
Get More in the Airmine Pollen app
Get 15-day pollen forecasts with morning, afternoon and evening detail, plus 5-day air quality forecasts. Explore interactive pollen risk maps, estimated pollen season start, route profiles and a symptoms diary.
Features and forecast availability vary by region. Currently covering Europe, the contiguous US, southern Canada, South Africa, Australia, Indonesia (Java & Bali), Brazil, Paraguay, Uruguay and the Buenos Aires area.
Developed with support from the European Space Agency (ESA) Business Applications and Space Solutions (BASS).
