Instant feels-like clarity. Compare today with yesterday or tomorrow with bold typography, Live Activities, widgets, and Home Screen Quick Actions.
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 when stepping outside: "How does today feel compared to yesterday?"
THE SCIENCE OF APPARENT TEMPERATURE
Ambient air temperature only tells half the story. Thermo Diem implements advanced biometeorological models (NOAA Wind Chill, Rothfusz Heat Index, and Steadman’s psychrometric heat balance) — calculating the thermodynamic 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.
• Direct Solar Radiation: Incorporates direct thermal gains from daylight and UV index.
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, DYNAMIC ISLAND & LIVE ACTIVITIES
Get temperature shift intelligence wherever you are. Thermo Diem brings real-time relative temperature and color-synchronized spectrum gauges to your CarPlay Dashboard, iPhone Lock Screen, and Dynamic Island—keeping you informed before your commute begins.
HOME & LOCK SCREEN WIDGETS
Bring iconic poster typography to your Home Screen and Lock Screen. Features bold, edge-to-edge circular lock screen widgets maximized for instant legibility, split overview cards, and signature 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.
NATIONWIDE MOVERS
Curious where the biggest swings are happening? Explore 24-hour temperature movers across major climate regions nationwide.
NOW IN 4 LANGUAGES
Full native support for English, Spanish, French, and German.
PRIVACY FIRST
No tracking, no third-party ad networks, and no data harvesting. Just clean, honest weather intelligence.
Currently reads "Tomorrow will feel similar to t…"
Julia
Jjhhhyyuisnis
I love this app I really recommend it for people who are on the go because it is easy to see it right away and compare today and the next days temps guys get it!!!!!😭🙏
Widget not current
Jambalayafjjdch
After I click on widget, only then it updates to the current weather. This defeats the purpose of being able to glance at the widget and have current information.
3.2 is a Game Changer
MickeyDeLo
Works on all of your devices
What's New in Version 3.5:
• Home Screen Quick Actions: Long-press (Haptic Touch) the app icon to jump to Tomorrow's Forecast, Nationwide Movers, or activate your Commute Live Activity.
• Reliable Widget Scheduling: Improved background refresh cadence for Lock Screen and Home Screen widgets.
• Tomorrow Outlook Polish: Smoother transitions and refined typography when previewing tomorrow's temperature shift.
• Performance & Stability: Memory optimizations and background task reliability enhancements.
• MacOS version
• What's New in Version 3.4:
• Commute Live Activity & Dynamic Island drive tracking.
• Smart automatic background refresh scheduled before morning waking hours.
• Deeper solar radiation and wind gust biometeorology modeling.
• What's New in Version 3.3:
• Multilingual support (Spanish, French, German).
• Editorial headline grammar refinements ("About the same as yesterday").
• Streamlined city and US state abbreviation labels.
• What's New in Version 3.2:
• Nationwide Movers: Real-time leaderboard tracking the largest 24-hour temperature swings across the country.
• Quick City Switcher to view any mover's climate delta.
• Enhanced Apple Watch Ultra and Series contrast.
• What's New in Version 3.1:
• Interactive 24-hour horizon scrubber to compare future hours with yesterday.
• Peak comparison toggle: "Same Time" vs. "Yesterday's High".
• Dynamic high-contrast palettes for extreme shifts.
• What's New in Version 3.0:
• Complete ground-up redesign with bold Anton typography.
• NOAA-grade biometeorological apparent temperature engine.
• Native standalone Apple Watch app with gauge needles.
• Modern Lock Screen and Home Screen widgets.
Version 3.5
The developer, Basic Function, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
Location
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
