Ragweed Pollen Count in Castro Valley, CA — Today

Pollen by type in Castro Valley

• Castro Valley tree pollen count
• Castro Valley grass pollen count
• Castro Valley pollen count

What is the ragweed pollen count in Castro Valley today?

The Castro Valley ragweed pollen index today is 28 (Low) on Pollen Atlas’s modelled 0–100 scale. Low

Modelled pollen risk index — not a measured count.

Ragweed pollen is the dominant allergen in Castro Valley today. See the full Castro Valley pollen count for the overall index and every type together.

Castro Valley is a census-designated place in Alameda County, California. Its population is 65,389 (ACS 2023).

Castro Valley Ragweed Pollen Count: 5-Day Forecast

Pollen Atlas models the daily detail as an overall index: day-by-day splits by individual pollen type are not part of the modelled data, so this table shows Castro Valley’s overall trend across the week. Today’s ragweed pollen reading is the headline above.

Species driving Castro Valley’s ragweed pollen

Species-level counts are not part of the modelled data Pollen Atlas publishes — the modelled index is reported per pollen type, not per species — so this section gives the type summary: ragweed pollen reads 28 (Low) today. The plant-by-plant detail that is available, from the Google Pollen API, is in the next section.

How to read this: the “ragweed” figure on this site is the modelled weed pollen index — the weed group (ragweed + mugwort) — printed under the ragweed name the rankings use.

Plants affecting Castro Valley now — ragweed pollen

Detailed plant-by-plant readings for the ragweed pollen category were not returned in today’s source data for Castro Valley. The type summary stands: ragweed pollen reads 28 (Low) today.

In the California pattern, the plants that typically shape this city’s year are winter and spring trees, late-spring grasses and late-summer weeds — named here as regional context only, not as today’s readings.

Plant detail returns here automatically on any day the feed includes it.

What this ragweed pollen level means

Low risk. Keep windows open; consider allergy meds only if sensitive.

Enjoy outdoor activities.

Weeds follow in late summer and fall, stronger after wet winters. This month sits outside the usual ragweed pollen window for the California pattern, so today’s ragweed pollen reading is the modelled value outranking the calendar — this page reports the modelled reading first. The California allergy season guide singles out planted olive and the Central Valley’s concentrated spring pollen.

Castro Valley allergies today

Castro Valley allergies today are set by the same reading as the Castro Valley pollen count today: the Total Pollen Index is 24 (Low), and the ragweed pollen index on this page is 28 (Low) of it. When people ask about Castro Valley allergies, this is the number that answers them — one daily modelled index built from today’s tree, grass and weed index values for Castro Valley.

Allergies in Castro Valley follow the California calendar set out on the full Castro Valley page — the chapters, the plants behind them, and the 5-day forecast show whether today is typical for the season or an exception to it. If you are checking allergies today in Castro Valley before heading outdoors, the ragweed pollen split on this page is the part to read: it shows whether this pollen type is doing the work today, not just how high the total sits.

Read the five-day overall trend above as the Castro Valley allergy forecast for the ragweed pollen season: it shows whether Castro Valley allergies are set to ease or build across the week, day by day — the days to plan outdoor time around are the ones where the overall index steps down, not just today.