Castro Valley pollen forecast - today, tomorrow and the week ahead
Today (9 August) pollen in Castro Valley is medium; mugwort and ragweed are medium; cypress and grass are low. Tomorrow (10 August 2026) levels are similar - mugwort declining, ragweed declining. Over the following five days grass, mugwort, and ragweed will increase; cypress will remain stable. Forecasts are calculated by Airmine using satellites to map local vegetation and determine pollen season onset.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Castro Valley's East Bay California setting features blue oak, California bay, and eucalyptus as the main tree pollen sources, with exposure varying between the extensively wooded chaparral hillsides of the Castro Valley hills and the more built-up commercial corridors along Castro Valley Boulevard. The elevation gradient between the oak and bay woodland above and the valley floor below creates distinct local pollen zones throughout the spring season.
Today - 9 August
-
Alder (Alnus):
None
0/100
-
Birch (Betula):
None
0/100
-
Hazel (Corylus):
None
0/100
-
Cypress (Cupressaceae):
Low
15/100
-
Grass (Poaceae):
Low
19/100
-
Willow (Salicaceae):
None
0/100
-
Mugwort (Artemisia):
Medium
35/100
-
Ragweed (Ambrosia):
Medium
45/100
High pollen levels may trigger sneezing, itchy eyes, and congestion. Airmine's neighbourhood estimates use satellites to map local vegetation and a statistical prediction model, updated four times daily.
Tomorrow - 10 August
-
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
9/100
-
Ragweed (Ambrosia):
Low
20/100
Air quality in Castro Valley
View air qualityFrequently Asked Questions
Is pollen high in Castro Valley right now?
On 9 August 2026, overall pollen levels in Castro Valley are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia, cypress, and grass remain at lower levels
Will pollen levels change in Castro Valley tomorrow?
On 10 August 2026, pollen conditions in Castro Valley will be different from today, with ambrosia, artemisia continuing to decline
Is pollen expected to decrease in Castro Valley this week?
According to the five-day outlook, grass, ambrosia, and artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Castro Valley?
On 9 August 2026, Ambrosia is the dominant pollen source in Castro Valley. artemisia, cypress, and grass are also present but at lower levels.
When is pollen season in Castro Valley?
How often is the Castro Valley pollen forecast updated?
The Castro Valley pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Castro Valley 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 Castro Valley 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 Castro Valley, 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.
Want to see pollen forecasts for other cities in United States?
Check pollen in other popular cities:
Data provided by Airmine — Last update: 10 August 2026 at 02:34 CEST (Data is updated four times daily.)
This page provides the latest public pollen forecast for Castro Valley.
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Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.