A sort of pretend euphenism for daylight saving time.  Of course, it is neither: it cannot really be called  ‘summer time’, extending as it does from March (spring) to a full month after the autumnal equinox.  And if we all had the middle of our day actually at midday, it wouldn’t be necessary to save on the daylight either.

Still, the increased sunny evenings are very nice (and it’s actually sunny today).