How about the fact that many English-speaking people [*] use the term "Daylight Savings Time"?
You wrote "all of English". I may consider Americans to be wrong about this, but they refer to "Daylight Savings Time" when asking me what happens in the UK.
Two separate points on collateral matters: In previous discussions on this list, the consensus has been that "Daylight Saving Time" (as opposed to "Savings") is correct. A few Web pages that confirm this are http://webexhibits.org/daylightsaving/b.html, http://en.wikipedia.org/wiki/Daylight_saving_time, and http://geography.about.com/cs/daylightsavings/a/dst.htm. I didn't find any that disagreed. I am American. I always use "daylight saving time" in my own speech. I would feel uncomfortable using "summer time" in oral discourse to mean the same thing. Why? Because it sounds exactly like "summertime", which refers to vacation and warm weather, not clock time. I don't think of "summer time" as wrong, but as British usage, like "lift" vs. "elevator" or 25/12/2005 vs. 12/25/2005. -- Gwillim Law