Fallback Manual for the Day-Ahead Market
Exchange of client certificates for XMtrade®/ISZO and XMtrade®/ISOT systems on 17th February 2026
Exchange of server certificate *.okte.sk on 3/3/2026
Commencement of the public consultation on changes to the OKTE, a.s. Operation Order
Central European Summer Time change on 03/29/2026, more...

Central European Summer Time Change

On Sunday, March 29, 2026, at 2:00 a.m., there will be a change from Central European Time (CET) to Central European Summer Time (CEST). This means that at 2:00 a.m. CET, the clocks will move forward to 3:00 a.m. CEST.

ISOT

The trading day on Sunday, March 29, 2026, will consist of 23 trading periods for hourly products and 92 trading periods for 15-minute products.

For 60-minute periods:

  1. trading period (t.p.) corresponds to the interval 0:00 – 1:00
  2. t.p. 1:00 – 2:00 (CET)
  3. t.p. 3:00 – 4:00 (CEST)
  4. t.p. 4:00 – 5:00, etc., up to
  5. t.p. corresponding to the interval 23:00 – 24:00

For 15-minute periods:

  1. trading period (t.p.) corresponds to the interval 0:00 – 0:15
  2. t.p. 0:15 – 0:30
  3. t.p. 0:30 – 0:45
  4. t.p. 0:45 – 1:00
  5. t.p. 1:00 – 1:15
  6. t.p. 1:15 – 1:30
  7. t.p. 1:30 – 1:45
  8. t.p. 1:45 – 2:00 (CET)
  9. t.p. 3:00 – 3:15 (CEST)
  10. t.p. 3:15 – 3:30 (CEST)
  11. t.p. 3:30 – 3:45 (CEST)
  12. t.p. 3:45 – 4:00 (CEST)
  13. t.p. 4:00 – 4:15 (CEST), etc., up to
  14. t.p. corresponding to the interval 23:45 – 24:00

The display of trading periods on the Trading Screen (VDT) for the trading day March 29, 2026, will be as follows:

  • The trading hour corresponding to the interval 0:00 – 1:00 will be labeled “00 – 01,” or on March 28, 2026, as “T00-01.”
  • The trading hour corresponding to the interval 1:00 – 2:00 (CET) will be labeled “01 – 02,” or on March 28, 2026, as “T01-02.”
  • The trading hour corresponding to the interval 3:00 – 4:00 (CEST) will be labeled “03 – 04,” or on March 28, 2026, as “T03-04.”

All other trading hours will correspond to local time (CEST), with the last trading hour being:

  • The trading hour corresponding to the interval 23:00 – 24:00 will be labeled “23 – 24,” or on March 28, 2026, as “T23-24.”

ISZO

The trading day on Sunday, March 29, 2026, will have 23 trading hours in 15-minute resolution, meaning that daily diagrams will contain 92 values (trading periods). 1st–4th t.p. correspond to the interval 0:00 – 1:00, 5th–8th t.p. 1:00 – 2:00 (CET), 9th–12th t.p. 3:00 – 4:00 (CEST), 13th–16th t.p. 4:00 – 5:00, etc., up to 89th–92nd t.p. corresponding to the interval 23:00 – 24:00

The intraday registration for the trading day March 29, 2026, will be processed in 23 time windows, corresponding to the respective trading hours. The 2nd intraday registration window will cover 1:00 CET – 2:00 CET. The 3rd intraday registration window will cover 3:00 CEST – 4:00 CEST.

The deadline for submitting changes to daily diagrams for a trading hour within intraday registration will be 15 minutes before the start of the respective trading hour, and the changes will be confirmed 5 minutes before the start of the respective trading hour.

ISOM/ISCF

Measurement types A and B and production sites for trading day March 29th, 2026 will consist of 92 periods. In case of submission of measured values through automated interface, 8th period will have range of 202603290145-202603290300.

RRM

Trading day for Sunday March 29th, 2026 will have only 23 trading hours. 1st trading hour will be equal to 0:00 - 1:00, 2nd trading hour will be equal to 1:00 - 2:00 (CET), 3rd trading hour will be equal to 3:00 - 4:00 (CEST), 4th trading hour will be equal to 4:00 - 5:00... until 23rd trading hour will be equal to 23:00 - 24:00.

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