Ragweed Pollen Count in Los Altos Hills, CA — Today

Updated Saturday, November 7, 2026

Pollen by type in Los Altos Hills

What is the ragweed pollen count in Los Altos Hills today?

The Los Altos Hills ragweed pollen index today is 25 (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 Los Altos Hills today. See the full Los Altos Hills pollen count for the overall index and every type together.

Los Altos Hills Ragweed Pollen Count: 5-Day Forecast

DayOverall indexCategory
Saturday, November 725Low
Sunday, November 825Low
Monday, November 924Low
Tuesday, November 1020Low
Wednesday, November 1120Low

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 Los Altos Hills’s overall trend across the week. Today’s ragweed pollen reading is the headline above.

Species driving Los Altos Hills’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 25 (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 Los Altos Hills now — ragweed pollen

Detailed plant-by-plant readings for the ragweed pollen category were not returned in today’s source data for Los Altos Hills. The type summary stands: ragweed pollen reads 25 (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.

Los Altos Hills allergies today

Los Altos Hills allergies today are set by the same reading as the Los Altos Hills pollen count today: the Total Pollen Index is 25 (Low), and the ragweed pollen index on this page is 25 (Low) of it. When people ask about Los Altos Hills allergies, this is the number that answers them — one daily modelled index built from today’s tree, grass and weed index values for Los Altos Hills.

Allergies in Los Altos Hills follow the California calendar set out on the full Los Altos Hills 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 Los Altos Hills 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 Los Altos Hills allergy forecast for the ragweed pollen season: it shows whether Los Altos Hills 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.

See the full Los Altos Hills pollen count — all types, the overall index and today’s ranking context

Los Altos Hills tree pollen count

Los Altos Hills grass pollen count

See how Los Altos Hills ranks in today's pollen count rankings — the worst cities for allergies today

See Los Altos Hills on the pollen map

Every pollen type, with photos and seasons: the pollen directory

California allergy season guide

Ragweed season

Find an allergist in Los Altos Hills, CA

Pollen indexes: a modelled pollen risk index computed by Pollen Atlas from open weather, vegetation and phenology data, calibrated against CDC/NAB season data. Plant detail: Google Pollen API. Index values are modelled, not measured counts. Sources: CDC/NAB; USA-NPN; GBIF (CC BY); ESA WorldCover (CC BY 4.0).