Observed arrival · 2026-09-20

ThermoDiem, a weather app with one reference point

thermodiem.com Visit website

Editorial interest 79/100 Selection signal · not a rating of the site

A minimalist iPhone and Apple Watch weather app that compares how the current weather feels with the same moment yesterday.

Landing page captured for the 2026-09-20 issue.

For: People who dress for how weather feels
Worth noticing: It compares feels-like conditions with the same moment 24 hours earlier, rather than presenting a conventional forecast dashboard.

Field notes

ThermoDiem reduces weather interpretation to a comparison with the same moment yesterday. Its stated calculation uses temperature, wind, and humidity, while the homepage preview shows a Philadelphia reading with a current value, a +3.5°F comparison, partly cloudy conditions, and a last-updated time. The site says the idea dates to 2013 and presents Widgets and CarPlay alongside the iPhone and Apple Watch app.

Observed signals

Read the marks

Editorial observations of this landing page, not a rating.

○OpenPublic substance visible

✦PrettyNotable craft visible

●ProPolished or operationally mature

◎NicheUnusually specific use

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