EDF's Tempo color update

In April 2025, a report detailed the sources available without a token to determine the Tempo color of the day, following the closure of EDF's old URLs. The season of red days resumes on November 1, with a new feature: forecasts beyond tomorrow in JSON and open data.

Understanding the Tempo color system

The Tempo option from EDF includes 300 blue days, 43 white days, and 22 red days per season. Red days fall between November 1 and March 31, never on a Saturday or Sunday, and the kWh is significantly more expensive on those days. The color for the following day is set by RTE and announced the day before.

Official sources for Tempo data

RTE is the official source for Tempo colors. Its API requires a user account and a token on RTE's data portal. Past colors are also published as open data: Tempo Like Supply Contract on data.gouv.fr.

Alternative open-source access

api-couleur-tempo.fr, mentioned in 2025, remains available. It provides simple JSON data without a key and is widely used in home automation forums. Calendrier Tempo EDF relays the official color via this source on /api/today and /api/tomorrow.

New forecast features

Since 2025, forecasts in JSON without an account are now available. Open DPE publishes a daily forecast file with a probability, and Calendrier Tempo EDF offers /api/predictions, which includes forecasts up to J+15, with color probabilities and temperature forecasts.

Reliability and verification

A forecast remains a forecast, and only the published color is reliable. The further the deadline, the more it is a trend than a certainty. Forum discussions from last winter show that forecasts without a history are uncertain, and Calendrier Tempo EDF provides a complete history of predictions, including errors, online and in downloadable CSV format.

Home automation integration

The API requires no account or key, and responses are cached for two minutes. Pre-configurations for Home Assistant, Jeedom, and Domoticz are available. API documentation is accessible on the Calendrier Tempo EDF website.

Community contributions and feedback

As in 2025, users are encouraged to share other sources without a token or track forecast reliability from their own perspective. Comments and feedback are available for discussion.