There's a gap between knowing the temperature and knowing whether to grab a coat. 14°C means very different things depending on whether you run cold, dress light year-round, or fall sick every season change. Generic forecast apps don't capture that.
Samukunai — 'are you cold?' in Japanese — is Niixo's attempt to close that gap without reaching for a machine learning model.
How it works
After stepping outside, you tap one of three options: 'felt cold,' 'felt fine,' or 'felt warm.' After 10 of those taps, an on-device statistics module we call ComfortEngine computes your personal 75th and 25th percentile comfort thresholds.
From that point forward, your morning push notification shifts from '14°C' to 'on the cold side for you' — or 'about right' — based on where today's forecast lands in your personal range. Processing stays on-device via SwiftData, with CloudKit sync across devices. Weather data comes from WeatherKit.
What we're honest about
Until you hit 10 taps, the experience is strictly worse than a standard weather app. You get less functionality without the personalization that justifies the extra interaction. No home screen widget yet. iOS 26+ only, which is a real constraint given where adoption sits today.
We shipped it anyway. The core problem — cold-tolerance is personal, raw temperature numbers don't capture it — doesn't disappear because the MVP has rough edges. Pure percentile statistics turned out to be a clean enough approach that we could ship without server-side inference or training data.
The stack
WeatherKit handles real-time conditions. SwiftData + CloudKit manages persistence and cross-device sync. ComfortEngine is a local statistics module — the one novel piece, with no external dependencies. The UI runs iOS 26 Liquid Glass.
Free. No ads. No in-app purchases.
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