Data Sources

Transparency matters when the data drives decisions about your day. Here’s where our forecasts come from and how we turn them into a single daily score.

Pollen forecasts

We use the Google Pollen API for daily tree, grass, and weed pollen levels. Forecasts are fetched once per day for each city we cover.

Pollen Score

Each location gets a 0–100 daily Pollen Score that combines tree, grass, and weed pollen levels using the Universal Pollen Index (UPI). Higher scores mean more potential for allergy symptoms. Learn how to read the forecast.

Update cadence

Forecasts are refreshed every morning. The “updated” timestamp on each location page reflects the most recent successful fetch.

Limitations

Pollen counts are forecasts, not measurements at your exact location. Local conditions (wind, rain, plants in your immediate vicinity) can differ from regional forecasts.