Winter time (clock lag)

Facsimile of the original issue of the Czechoslovak public journal with the act 212/1946 Sb. and the government ordinance 213/1946 Sb.

Winter time is the practice of shifting the clock back (compared to the standard time) during winter months. It is the opposite compensation to daylight saving time (summer time). However, while summer time is widely applied, application of winter time was very rare, maybe unique in history.

Winter time was applied in Czechoslovakia by the government ordinance no. 213/1946 Sb. from 1 December 1946 (3:00→2:00) to 23 February 1947 (2:00→3:00), authorized by the act 212/1946 Sb., o zimním čase ("about the winter time"). This simple two-paragraph act, approved on 21 November 1946 and announced on 27 November 1946, authorised the government to implement winter time by ordinance at any time. The government gave as the main reason for this provision the fact that power plants had approximately 10% lack of capacity in peak hours (7–8 and 16–20) and winter time should help to spread the load out.

The act was never canceled and it theoretically authorises the government in the successor Czech Republic, as well as in the Slovak Republic, which adopted Czechoslovak law, to implement winter time again at any time. However, the experiment has never been repeated.

This application of winter time is considered to be unique in the world. However, the Soviet Union used two levels of summer time (+1, +2) during World War II.