Question 1

What is AQI?

Accepted Answer

Air Quality Index. A single number that summarizes how clean or polluted the air is — lower is better. This page uses the European AQI scale: under 20 is good, 20–40 fair, 40–60 moderate, 60–80 poor, and 80+ very poor. Turn the AQI overlay on in the Customize sheet to see it as a colored band behind the graph.

Question 2

What does grains/m³ mean?

Accepted Answer

Grains of pollen per cubic meter of air — basically how many pollen particles a sensor counts in a box of air the size of a washing machine. Bigger number = more pollen floating around.

Question 3

What counts as Low, Moderate, High, or Very high?

Accepted Answer

Thresholds vary slightly by source, but a common guide: Grass — Low under 10, Moderate 10–49, High 50–199, Very high 200+. Tree — Low under 15, Moderate 15–89, High 90–1499, Very high 1500+. Weed — Low under 10, Moderate 10–49, High 50–499, Very high 500+.

Question 4

Where does the data come from?

Accepted Answer

Pollen and air quality come from Open-Meteo's free air-quality API. Your approximate location comes from your IP address, or a US zip code you enter. If your area doesn't have live readings, we fall back to a seasonal estimate derived from historical data and your latitude.

Question 5

What do Today, This week, Past years, and a Year of data show?

Accepted Answer

Today shows a single-day comparison: this year vs the same date last year vs two years ago, as a bar chart. This week shows a 7-day forecast with the same comparison as faint lines. Past years shows the last 30 days against the previous two years. A Year of data shows the full seasonal curve from January through December for all three years.

Question 6

Why do the lines have dashes and dots?

Accepted Answer

Solid = this year. Dashed = the same dates last year. Dotted = two years ago. Comparing them helps you tell if today's pollen is normal for this time of year or unusually high.

Question 7

What is the red line on the graph?

Accepted Answer

A red vertical marker at today's date, so you can see at a glance where you are on the time axis. The left edge of the highlighted area is always now.

Question 8

How do I read the colors?

Accepted Answer

Green = grass pollen, brown = tree pollen, olive/weed = weed pollen. The band shading behind each line marks the Low → Very high level zones for that pollen type. The AQI overlay, when turned on, adds a green-to-red air-quality band.

Question 9

What is the Customize sheet for?

Accepted Answer

Tap the location pill at the top of the graph to open it. You can change your location, switch between Today / This week / Past years / Year, and turn the Grass, Tree, Weed, and AQI series on or off. Hit Rebuild graph to apply.

Question 10

How do I change my location?

Accepted Answer

Tap the location pill at the top of the graph, then enter a US zip code and confirm. The graph will rebuild for that area. The city page link in the results takes you to a dedicated page for that metro.

Question 11

What does the Details button do?

Accepted Answer

Details toggles the chart's axes, gridlines, and legend overlay on top of the graph — useful when you want to read off exact values or share a screenshot with context. It does not change the data.

Question 12

Why is there no data for my area?

Accepted Answer

Open-Meteo doesn't have live pollen stations everywhere. If your region isn't covered, the graph falls back to a seasonal estimate, which may look flatter or less detailed than live data — and past-years comparison lines will be estimated too.

Question 13

How often is the data updated?

Accepted Answer

Pollen forecasts are typically updated daily. The graph pulls fresh data each time you load the page or change your location, so refreshing will get the latest available forecast. Your settings (location, time range, toggles) live in your browser.

Question 14

Are there city pages or rankings?

Accepted Answer

Yes — every city we cover has its own page with a full-year pollen curve and peak month breakdown. We also publish a yearly ranking of the worst US cities for allergies, updated each season.

Question 15

Should I do anything if levels are high?

Accepted Answer

If you're sensitive, common tips include keeping windows closed during your peak month, showering after time outdoors, and talking to a pharmacist or doctor about over-the-counter antihistamines. This site is informational, not medical advice.

Question 16

Does this site use my data?

Accepted Answer

We use your IP for approximate location only. Nothing is stored on our servers — your preferences live in your browser. See the Privacy Policy for the full details.

Pollen Count Graph FAQ