What is relative temperature?
How warm or cold it feels compared to what you're used to.
60°F in early March feels like a gift. 60°F in mid-August feels like a cold snap. Your body (and your brain) judges weather against what it has gotten used to — the season and the last few days. Relative Temperature puts a number on that.
The formula, in plain English
1. What you're "used to." We blend three things, all at the current hour of the day:
- 50% — the 30-year normal temperature at this hour (±3 days around today's date)
- 35% — the temperature at this hour yesterday
- 15% — the temperature at this hour two days ago
2. Relative temperature = 1.75 × today's feels-like − 0.75 × used-to.
In other words: start from today's feels-like temperature and push it further in whichever direction it differs from what you're used to. If it's 10° warmer than you're used to, it reads about 7.5° warmer still.
FAQ
Why not just show the real temperature?
Your weather app already does. This answers a different question: "Will this feel warm or cold to me today?"
What does "feels-like" include?
Wind chill and heat index — the apparent temperature from the forecast.
Where does the data come from?
Open-Meteo forecast and historical archive, free and open weather data. ZIP lookups via Zippopotam.us.
Does it work everywhere?
Any US ZIP code, for now.
Can I install it?
Yes — it's a web app. On your phone use "Add to Home Screen."
Is it free? Do you track me?
Free. Your last ZIP is saved only on your device so it loads next time.
Who made this?
Cory Freeman of Mahomet, Illinois (also behind 217 BBQ Company and Uncle Bubby's BBQ).
