Today DST it is almost always 1 hour ahead of normal time, but several other variants have been used during the course of history, such as half adjustment (30 minutes), double adjustment (2 hours), and even adjustments of 20, 40 minutes. Double adjustment was used in several countries for some years in the 1940's. Half adjustment was used in New Zealand in the first half of this century. Sometimes DST is used for longer periods than just the summer. From 3 February 1942 to 30 September 1945 most of the USA had DST all year, including the winter.