Tattis.Tattis — the mushroom forecast that shows the right forest and the right moment.

Tattis's heatmap combines three factors: a habitat model for the species, daily weather conditions, and the time of year.

• Habitat (stable): each species has its own model trained to predict the suitability of a location. The model uses forest type, tree cover, soil, elevation and vegetation indices, plus thousands of observations from laji.fi.
• Weather (updated daily): from the Finnish Meteorological Institute's open data, we calculate for each species whether the past few weeks of rain, temperature and night frosts support fruiting body growth right now.
• Season: every species has its own growing season. Outside that window, the forecast drops to zero.

The product of these three factors sets the map colour: pale yellow means low probability, deep red means high probability.

Tattis tells you where and when mushrooms are most likely to appear, but it doesn't guarantee it.

• The forecast is statistical. Weather stations are sparsely distributed, forest inventory updates with a lag, and local conditions vary with tree cover, slope and microclimate.
• The map guides, it doesn't find. Red and orange shades mean an area is potentially suitable in the current conditions, not that there are mushrooms there right now.
• Always identify each mushroom yourself. Edible species have toxic look-alikes. If you're not absolutely sure, leave the mushroom in the forest.

Use Tattis as a tool for trip planning and choosing where to go. Trust your eyes, your hands and your field guide when you actually pick. When in doubt, ask experienced foragers, for example in the Finnish Mycological Society's Facebook group.

An unusually early find like this isn't currently reflected in the forecast. Each species has its own growing season, and outside it the forecast is zero, so that a single early find doesn't shift the forecast for the whole country or trigger false alerts. This is a limitation of the model, not a bug — we train the species models continuously, and the timing of the seasons gets more accurate year by year. You can still log your find in the app and submit it to laji.fi, where it shows on the map regardless of season.

Yes, the basics of Tattis are free. The free version includes:

• Search and the 19 edible species recommended by the Finnish Food Authority
• Marking your own mushroom spots and notes
• When signed in, cloud sync of your observations and submission to laji.fi
• Nature reserves and parks on the map

A Pro pass unlocks the full app.

Pricing:

• Month €3.99 (auto-renewing)
• Year €12.99 (auto-renewing)
• Lifetime €69.99 (one-time, does not renew)

Pro features:

• All 32 species: including ones outside the Finnish Food Authority list, like the spring agaric and other rarer treats
• Mushroom heatmaps: species-specific probability visualisations for the whole of Finland
• Forest-type maps: groves, heathland and other Luke forest categories
• Species-specific weather: each species has its own rain and temperature thresholds, so the same forecast scores differently for chanterelle and porcini.
• Offline maps: MBTiles downloads to your phone with lightweight delta sync; works without a signal
• Push notifications: get an alert when conditions for your favourite species turn favourable in your region
• All future AI features at no extra cost

Payments are handled directly via the App Store or Google Play, using your preferred payment method.

Pro subscriptions (monthly and yearly) renew automatically. You can cancel any time. The cancellation takes effect at the end of the current period, and you keep Pro features until then.

There are three ways to cancel.

In the Tattis app:

1. Open Settings.
2. Select ”Manage subscription”, which opens the right page in your device's app store.

iPhone or iPad:

1. Open Settings.
2. Tap your name at the top.
3. Select Subscriptions.
4. Select Tattis Pro.
5. Select Cancel Subscription.

Android:

1. Open the Google Play Store.
2. Tap your profile picture.
3. Select Payments and subscriptions.
4. Select Subscriptions.
5. Select Tattis Pro.
6. Select Cancel subscription.

Cancel at least 24 hours before your next billing date, otherwise the next period will still be charged automatically.

Lifetime is a one-time purchase and does not renew, so there's nothing to cancel.

When the period ends the app reverts to the free version. Your observations, notes and foraging trips are kept, and you can re-enable Pro any time.

Many probability-based apps use a similar static approach (forest data + habitat requirements), but Tattis adds a dynamic weather layer and phenology, meaning it predicts when mushrooms appear, not just where. So there's no point heading out for chanterelles back in May.

Thanks for helping make Tattis better! Send a support request by email to support@laiton.ai. Tell us what happened and on which device, so we can fix the issue faster.