Know your pollen
before it knows you.

In towns and cities grass pollen often peaks in the evening rather than at midday. Pollen released in the countryside during the morning is lifted high into the air as the ground warms, then settles back to street level as the air cools after sunset. In rural areas the pattern is usually reversed and the worst hours are in the morning.

Polly draws an hour-by-hour curve for your location so you can see which pattern you actually live with instead of assuming. More detail in grass season, hour by hour. The hourly curve comes from the European CAMS model, so it is available in Europe only.

A single pollen count is an average across several species, and you are probably only sensitised to some of them. A day can be genuinely low overall while the one tree or grass that affects you is high. The bands are wide too: the lowest band typically stretches from nothing at all to enough to ruin a morning.

Polly weights the per-species forecast for your location against the allergens in your own profile, and always lists which species are driving the number, so a score you disagree with can at least be interrogated. The longer version is here.

Polly breaks the forecast down by species rather than showing one combined figure, so you can tell whether today is birch, grasses, mugwort or something else, and it carries a 5-day outlook for planning around the heavy days.

Worth knowing what that number is: forecasts come from the Google Pollen API and Open-Meteo, and both are models built from weather, land cover and the flowering calendar rather than someone counting grains on a slide. They are a good estimate of the day’s shape, not a reading of the air outside your window.

Rain washes pollen out of the air and that relief is real, but it is short. The plants keep flowering throughout, and a dry, breezy spell afterwards reloads the air quickly.

Thunderstorms are the exception to “rain helps”. The gust front ahead of a storm stirs pollen up, and humidity can burst grains into fragments small enough to reach the lower airways. If you have asthma as well as hay fever, the half hour before a summer storm breaks is the wrong time to be outside.

No, and it would be wrong to imply otherwise. Only a doctor can diagnose an allergy, using a skin prick test or a specific IgE blood test. Polly is a consumer wellness app, not a medical device and not a test.

What it can do is record how you felt against what was actually in the air, so that after a season you have a written record of patterns worth taking to an allergist. That is a starting point for a conversation, not a diagnosis.

It depends which pollen you react to, which is why one end date is not much use. Across northern and central Europe, trees run roughly from late winter into spring, grasses take over from late spring through midsummer, and weeds such as mugwort and ragweed carry on into autumn.

Polly shows which species are active where you are, so “is it over yet” becomes a question about your allergens rather than about the calendar.

The daily forecast covers more than 65 countries, and you can use your current location or search for any city. Coverage is honestly uneven, so: Europe and North America get tree, grass and weed; Australia gets grasses and trees; New Zealand, South Africa and most of South America get grasses only. Polly hides a category rather than showing you a permanent zero.

The hour-by-hour curve and the Explorer heatmap rest on a European model and are available in Europe only. The app itself is in 35 languages, and is iPhone only for now.

No. Polly is a subscription app: using it needs Polly Pro, which comes as a weekly, monthly or yearly plan. The yearly plan includes a 7-day free trial for new subscribers, so you can see a real week of your own data before paying anything. Prices vary by region and are shown on the paywall in the app.

There are no ads, no account to create, and nothing is sold on. Your diary stays on your device and in your private iCloud. Cancel any time in iOS Settings.