Tempo seasons since 2014
Every winter since RTE started choosing the colours: how many red days, when they fell, and what they would have cost you.
RTE has chosen the Tempo colours since 1 November 2014, and every one of its publications can still be looked up: 12 seasons are complete, from 2014-2015 to the latest, and the current one fills in day by day. Each completed season had 22 red days and 43 white days, except 2019-2020, which ended on 18 red and 47 white after the energy regulator, the CRE, had red days replaced by white ones from 19 March 2020. What really changes from one winter to the next is timing: the first red day has fallen as early as 29 November 2023 and as late as 8 January 2016; the last one between 27 January 2022 and 31 March 2017. Pick a season in the tool to see its day-by-day calendar and what its red days would have added to your bill at today’s prices.
Season 2025-2026: red days
22
43 white, 300 blue
| First red day | 29 December 2025 |
| Last red day | 31 March 2026 |
| Longest red run | 5 days |
| Extra cost of red days for you | €354 |
Extra cost: each red day against a blue day with the same use, 30% at night, prices from 1 August 2026.
Sept 25
Oct 25
Nov 25
Dec 25
Jan 26
Feb 26
Mar 26
Apr 26
May 26
Jun 26
Jul 26
Aug 26
Checked by Radif Partners · Editorial policy · Method and sources
Every season, one row each
| Season | Red | White | Blue | First red | Last red | Longest run |
|---|---|---|---|---|---|---|
| 2026-2027 (current) | 0 | 0 | 48 | none yet | none yet | |
| 2025-2026 | 22 | 43 | 300 | 29 December 2025 | 31 March 2026 | 5 d |
| 2024-2025 | 22 | 43 | 300 | 3 December 2024 | 3 February 2025 | 5 d |
| 2023-2024 | 22 | 43 | 301 | 29 November 2023 | 29 March 2024 | 5 d |
| 2022-2023 | 22 | 43 | 300 | 8 December 2022 | 2 March 2023 | 5 d |
| 2021-2022 | 22 | 43 | 300 | 29 November 2021 | 27 January 2022 | 5 d |
| 2020-2021 | 22 | 43 | 300 | 2 December 2020 | 11 February 2021 | 5 d |
| 2019-2020 | 18 | 47 | 301 | 4 December 2019 | 6 March 2020 | 5 d |
| 2018-2019 | 22 | 43 | 300 | 11 December 2018 | 29 March 2019 | 5 d |
| 2017-2018 | 22 | 43 | 300 | 1 December 2017 | 28 February 2018 | 5 d |
| 2016-2017 | 22 | 43 | 300 | 29 November 2016 | 31 March 2017 | 5 d |
| 2015-2016 | 22 | 43 | 301 | 8 January 2016 | 29 February 2016 | 5 d |
| 2014-2015 | 22 | 43 | 300 | 4 December 2014 | 11 February 2015 | 5 d |
The table is recalculated at every reading from RTE’s calendar. Every completed season keeps to the rules of the 2014 deliberation: no red day on a Saturday, Sunday or public holiday, none outside 1 November to 31 March, never more than five in a row, no white day on a Sunday. Our tests check this day by day before every release.
What twelve winters tell us
A run of five red days, Monday to Friday, happened in 12 of the 12 completed seasons: it is the longest the rule allows, and RTE uses it during cold spells that last a week. The date of the first red day, on the other hand, moves by several weeks. A household waiting for “the first red day in December” before getting organised has sometimes been caught out in late November and has sometimes waited until January.
The share of heating that falls on red days
| Season | Heating on red days | Heating on white days | Average demand on a red day |
|---|---|---|---|
| 2025-2026 | 15.5 % | 28.0 % | 62,523 MW |
| 2024-2025 | 20.1 % | 31.4 % | 69,194 MW |
| 2023-2024 | 21.0 % | 28.6 % | 66,978 MW |
| 2022-2023 | 23.8 % | 29.4 % | 71,005 MW |
| 2021-2022 | 19.9 % | 27.4 % | 74,512 MW |
| 2020-2021 | 20.6 % | 28.2 % | 74,544 MW |
| 2019-2020 | 15.5 % | 29.9 % | 69,928 MW |
| 2018-2019 | 19.4 % | 29.0 % | 73,741 MW |
| 2017-2018 | 18.8 % | 30.7 % | 75,895 MW |
| 2016-2017 | 18.7 % | 30.1 % | 74,422 MW |
| 2015-2016 | 19.3 % | 30.2 % | 72,542 MW |
| 2014-2015 | 20.7 % | 30.3 % | 76,423 MW |
With the éCO2mix data you can see how much a winter weighs. A season whose red days matched genuine cold spells puts over a fifth of the country’s heating on them; a mild season, or 2019-2020 with its swapped red days, far less. The comparison tool uses the average of all completed seasons, so as to bet neither on a harsh winter nor on a gentle one.
Replay a season on your own use
The tool at the top counts, for the season you pick, how much more its red days would have cost you than blue days, at the 1 August 2026 tariff and for a winter day of the consumption you enter. It is a simple way to measure the gap between two winters; to choose your option, use the full annual calculation, and for the season under way, the Tempo days left page.