No, this isn’t an allusion to what happened all those years ago in Montreux, but to the behaviour of the Atlantic Jet Stream, the high level winds that influence the movement of weather systems in our part of the Northern Hemisphere. The “misfire” is what those winds have been doing recently.
Although this journey into meteorology might sound a little highbrow, it’s not difficult to understand. Customarily, the north Atlantic Jet Stream passes to the north of Scotland, with weather systems following from the south west. Hence the relatively mild weather enjoyed by the UK, considering its latitude [this Wiki article goes into rather more detail].
So far, so routine, but over the past three years, that Jet Stream has often tracked further south, brought winds from the north west rather than south west, or even broken up, the last allowing weather patterns to persist over the UK – not a welcome occurrence when that happens in winter and brings very cold winds from the Arctic.
A Jet Stream bringing high level winds from the north west was what we got in April last year: that carried volcanic ash from Iceland and scattered it across Europe. And while the UK had average or slightly cooler temperatures, central Portugal was roasting at over 30 Celsius, which often happens in high summer, but not before the end of April.
You can follow the behaviour of the Atlantic Jet Stream at this site. Right now, it’s still suffering that misfire.