Jackson Hole is Davos for central bankers. Each year, the maestros of monetary policy show up in the Grand Tetons, Wyoming, to show that they know how to have a good time. For central bankers that means listening to erudite academic papers on quantitative easing and discussing Milton Friedman’s theory of helicopter money.

As far as the markets are concerned, though, only one thing matters at this year’s meeting: whether Janet Yellen gives any clues as to the timing of the next increase in interest rates from the US Federal Reserve.

Wall Street is agog for two reasons. Firstly the recent economic news from the world’s biggest economy has been pretty good. Secondly Yellen’s No 2 at the Fed, Stanley Fischer, made some hawkish comments at the weekend which left a clear impression that an increase in borrowing costs this year remained on the agenda.

Predictably the idea that the Fed is contemplating a rate rise while all the other major central banks are looking to provide more stimulus led to a stronger US dollar and weaker commodity prices.

But, as Wall Street should not need to be reminded, we have been here before. At the start of the year there was speculation that there would be four increases in interest rates during the course of 2016. So far there have been none. The Fed has given strong signals that interest rates are going up only to back away again in the face of downbeat economic data.

Three possible dates have been pencilled in by the markets for a Fed move: September, December and March next year. September will be a non-starter unless Yellen comes up with some uncharacteristically tough and unequivocal words in Jackson Hole. She is is an instinctive dove, doesn’t especially want to see the dollar appreciate rapidly is and politically smart to boot. A September rate rise would come smack in the middle of the presidential election race.

It is more probable that the choice is between December and March. The recent data points to December. The Fed’s recent actions point to March.