Pollen & allergy guides

How pollen data actually works, what the numbers mean, and how to use them without being misled.

• Why Do Pollen Apps Disagree? We Compared 175 Place-Days Against Real Pollen Counts

  Original measurement: two widely used sources agreed only about half the time. Here is the data.

• What Is the Universal Pollen Index (UPI)? The 0–5 Pollen Scale Explained

  0 to 5, what each band means, and why it is not comparable to the 0–12 scale.

• Ragweed Season: When It Starts, When It Peaks, and How to Track It

  When ragweed starts, why it peaks in September, and how to follow it.

• A Pollen.com Alternative for iPhone: Pollenary

  Per-plant detail, per-allergen alerts, and a severity source we verified.

• The Best Pollen and Allergy Forecast Apps in 2026 (and How to Judge Them)

  What to look for, and why the numbers disagree between apps.

• Which Pollen Am I Allergic To? How to Work It Out From the Calendar

  Match your bad weeks to the pollen calendar to narrow it down.