Thermo Diem

Most weather apps give you numbers. Thermo Diem gives you context.

A 72° day after a week of freezing cold feels completely different than 72° after a scorching heat wave. That’s because human comfort is relative — your physiology adapts to what you experienced yesterday.

Thermo Diem compares current apparent temperature directly to yesterday, tomorrow, and future days of the week, answering the only question that matters: "What should I wear today?"

THE SCIENCE OF APPARENT TEMPERATURE
Ambient air temperature only tells half the story. Thermo Diem implements Robert Steadman’s biometeorological formula — calculating the thermodynamic heat balance between human skin and the surrounding atmosphere:
• Vapor Pressure & Humidity: Accounts for evaporative cooling resistance.
• Wind Velocity: Measures forced convective heat loss from exposed skin.
• Solar Radiation: Incorporates direct thermal gains.
The result is true Apparent Temperature, evaluated directly against your recent baseline.

7 INTUITIVE SHIFTS
Pure clarity with zero clutter:
• Much Warmer
• Warmer
• A Little Warmer
• About The Same
• A Little Cooler
• Cooler
• Much Cooler

TREND CURVES & FUTURE SHIFT
See today’s feels-like trajectory overlaid directly on yesterday’s curve. Use the 7-day Future Shift dial to scrub ahead and compare any upcoming hour or day of the week against right now or yesterday's high.

CARPLAY & COMMUTE LIVE ACTIVITIES
Get temperature shift intelligence right on your car's dashboard. Thermo Diem brings real-time relative temperature and signature spectrum gauges to CarPlay Dashboard and Lock Screen Live Activities—keeping you informed before your commute begins.

HOME & LOCK SCREEN WIDGETS
Bring iconic poster typography to your Home Screen and Lock Screen. Choose from bold multi-line posters, split overview cards, or spectrum slider gauges. Long-press any widget to customize comparison targets and display details.

STANDALONE APPLE WATCH APP
Designed natively for your wrist. Check today's shift at a glance with rapid launch, custom watchOS complications (Corner, Circular, Rectangular, Inline), and independent background updates.

PRIVACY FIRST
No tracking, no third-party ad networks, and no data harvesting. Just clean, honest weather intelligence.