San Lorenzo, CA Pollen Count Today
San Lorenzo, CA · Updated Saturday, November 7, 2026
Pollen Overview
Today's overall pollen level and the dominant type (trees, weeds, grass, or mold).
Total Pollen Index
The combined pollen level across all types (0–100).
San Lorenzo, CA
Weeds Index
How active weeds pollen is today (0–100).
San Lorenzo, CA
Pollen Types
Pick a pollen subtype to update the species forecast
5-Day San Lorenzo Overall Pollen Forecast
Bars are colored by severity (Low/Moderate/High).
This reading is the forecast point shared with San Leandro, CA — 2 nearby places use the same point; San Lorenzo is 5.7 km from it.
Pollen count San Lorenzo residents check each morning
The San Lorenzo pollen count today is 24 (Low). The main driver is Ragweed, with weed pollen at 28 today. That total sits on a narrow base: weed pollen is 28 while tree pollen is just 25 and grass pollen 1. Plant-by-plant detail for San Lorenzo, CA follows, along with the outlook for the days ahead. Pollen Atlas updated this count on Saturday, November 7, 2026.
A Low band on the Pollen Atlas index means the Total Pollen Index has stayed in the lower part of the 0–100 scale. Readings in this band are built from low individual category values rather than from one large spike, and the category split above matters more than the headline number: a low total can still contain one category, such as weed pollen or mold, reading noticeably higher than the rest, which is why the split is printed on every San Lorenzo page.
Fall is ragweed season across most of the United States: ragweed plants release pollen from late summer into autumn, and weed pollen is typically the last major outdoor pollen category to fade as the weather cools. That pattern is why an autumn total is so often weed-led even when the headline number is low — tree and grass pollen have usually receded by then, leaving weed pollen, and on damp days mold, to make up most of what the index records.
To see whether today’s pollen level holds, check the 5-day San Lorenzo pollen forecast below — it is currently mixed, with Monday the highest day in the window.
This is the pollen count San Lorenzo residents check each morning, built from the day’s tree, grass, weed and mold readings.
What is the San Lorenzo pollen count today?
The San Lorenzo pollen count today is 24 out of 100 (Low) on the Pollen Atlas Total Pollen Index, driven mainly by Ragweed.
Short answer for anyone searching pollen count today San Lorenzo: this page is updated every morning with the day’s modelled reading.
San Lorenzo allergies today
San Lorenzo allergies today are set by the same reading as the pollen count above: the Total Pollen Index is 24 (Low), driven mainly by Ragweed. When people ask about San Lorenzo allergies, this is the number that answers them — one daily index built from today’s tree, grass, weed and mold readings for San Lorenzo.
Allergies in San Lorenzo follow the California calendar set out below — the chapters, the plants behind them, and the 5-day forecast on this page show whether today is typical for the season or an exception to it. If you are checking allergies today in San Lorenzo before heading outdoors, the split at the top of this page is the part to read: it shows which pollen is doing the work today, not just how high the total sits.
Read the five-day table on this page as the San Lorenzo allergy forecast: today reads 24 (Low), and the day-by-day outlook shows whether San Lorenzo allergies are set to ease or build across the week — the days to plan outdoor time around are the ones where the index steps down, not just today.
In practice, the allergy count San Lorenzo today records is this same combined reading — tree, grass, weed and mold in one index.
The San Lorenzo allergy count today is 24 (Low) — the same Total Pollen Index as the pollen count above, in one combined reading.
Pollen count today San Lorenzo: the 5-day forecast
| Day | Total Pollen Index | Band |
|---|---|---|
| Saturday, November 7 | 24 | Low |
| Sunday, November 8 | 24 | Low |
| Monday, November 9 | 27 | Low |
| Tuesday, November 10 | 24 | Low |
| Wednesday, November 11 | 24 | Low |
Pollen Atlas forecasts San Lorenzo’s pollen count to peak on Monday at 27 (Low) over the next 5 days.
Pollen by type in San Lorenzo
What is driving San Lorenzo’s pollen today
The shape of today’s 24 (Low) is set by weed pollen at 28 (Low on its own scale) — about 52% of the four category readings added together, 3 points clear of the next category, tree pollen at 25. A weed-led total is the classic late-year shape: tree and grass pollen have usually receded, leaving weed pollen — and on damp days mold — to make up most of what the index records. Weed pollen leading in November runs against the usual calendar — the California weed chapter runs August to October — so today’s lead is the model outranking the pattern, and this page reports the modelled reading first.
Plant-level detail is not in today’s feed for San Lorenzo, so the drivers have to be read from the category split above. The California guide’s account of California names planted olive and the Central Valley’s concentrated spring pollen — the pollens behind readings of this shape in this state — and the split shows how much of today’s total each category is actually carrying.
Across the five-day window the Total Pollen Index runs from 24 to 27, never changing band. Today’s 24 sits 1 point below the window’s average of 24.6 — a steady window, in which one day reads much like the next.
Plants affecting San Lorenzo now
Detailed plant-by-plant readings for San Lorenzo were not returned in today\u2019s source data, so this section summarises the pollen types the index above is built from instead of listing individual plants.
Tree pollen is one of the categories with a non-zero reading today, at 25 (Low).
Grass pollen is one of the categories with a non-zero reading today, at 1 (Low).
Weed pollen is one of the categories with a non-zero reading today, at 28 (Low).
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\u2019s measurements.
Plant detail returns here automatically on any day the source data includes it.
Every pollen type, with photos and seasons: the pollen directory.
San Lorenzo pollen through the year
Chapter by chapter, the San Lorenzo pollen year runs like this:
- Trees build through spring, with planted olive peaking from March into May.
- Grasses peak in spring in the Central Valley and run longer and milder on the coast.
- Weeds follow in late summer and fall, stronger after wet winters.
The California allergy season guide names planted olive and the Central Valley’s concentrated spring pollen. There is no single California season: the Central Valley records some of the state’s sharpest spring peaks, trapped and concentrated by valley geography, while the coast runs long and mild. The AAFA’s 2025 Allergy Capitals research noted upward movement for several California cities, attributed to grass and weed pollen after wet weather.
November falls between the main chapters of the California pollen year — the tail of one and the approach of the next — so the calendar alone explains little today, and the modelled split above carries the story. Between them, the three chapters cover 9 months of the California year, February to October — leaving a quiet gap of roughly 3 months in the depth of the off-season. The full calendar is set out in the California allergy season guide.
How to read this index
Pollen Atlas reports the San Lorenzo pollen count on a Total Pollen Index from 0 to 100, built from separate tree, grass and weed readings. The total is a summary, not an average of the three: a single strong category can lift it, and three quiet categories can hold it down even in a month when San Lorenzo, CA pollen is usually more active. Index values are a modelled pollen risk index computed by Pollen Atlas from open weather, vegetation and phenology data, calibrated against CDC/NAB season data, with plant detail by the Google Pollen API. The index is a modelled 0–100 scale, not a measured count, and figures update through the day, so a morning and an evening visit to this page can legitimately show different numbers.
San Lorenzo in today’s national picture
At 24 (Low), San Lorenzo ranks joint 37388th of the 90896 cities Pollen Atlas tracks today — in the middle of the national table. The highest reading in the country today is Beja, Portugal at 52, and the lowest is Los Ángeles de San Rafael, Spain at 5. The whole table spans 47 points today — a wide-open day, when the top and bottom of the table are effectively in different seasons.
Around San Lorenzo: Ashland, CA (2 miles away) reads 24 (Low); Cherryland, CA (2 miles away) reads 24 (Low); San Leandro, CA (2 miles away) reads 28 (Low). San Lorenzo reads exactly level with its nearest tracked neighbour today. Across California’s 1602 tracked cities, today runs from 5 in Truckee to 42 in Mecca.
Pollen totals are population numbers; symptoms are personal. The same reading can leave one San Lorenzo resident untouched and floor another, depending on which pollens they are sensitised to. If this pattern finds you every season, allergists in San Lorenzo, CA can test whether tree, grass, weed or mold is the category that matters for you — the four readings at the top of this page are the starting point for that conversation.
San Lorenzo in its local area
San Lorenzo is a census-designated place in Alameda County, California. Its population is 29,453 (ACS 2023).
San Lorenzo sits 2 miles southeast of San Leandro, CA — the anchor of the forecast-point group this reading belongs to. Within the group of 2, San Lorenzo ranks 2nd; across California’s 1602 tracked cities, it ranks joint 437th today.
Like every Pollen Atlas city page, the San Lorenzo, CA pollen count is refreshed each morning.
Nearby cities
- Ashland pollen count (2 miles away)
- Cherryland pollen count (2 miles away)
- San Leandro pollen count (2 miles away)
- Hayward pollen count (4 miles away)
- Castro Valley pollen count (5 miles away)
- Fairview pollen count (5 miles away)
From Pollen Atlas News
See how San Lorenzo ranks in today's pollen count rankings — the worst cities for allergies today
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).