What does the oil market know that Tony Blair didn't know?
That you get hurricanes in the Caribbean at this time of year.
That is why last week's promising relapse in the price of crude stalled the moment it fell below $66 just as those pictures of our Prime Minister showing off his smart new bathing trunks found their way into the public prints.
This year's hurricane season got off to a lively start, too, before the Blairs set out. In early July parts of Cuba were devastated by Dennis, which moved on to the Gulf of Mexico and left a huge BP oil platform looking groggy.
By yesterday the alphabet had progressed to Jose, which was closing in on Mexico. Further out in the Atlantic a "large tropical wave" was surging ominously westwards, according to the US National Weather Service.
The bad news for Gordon Brown, who prudently recharges his batteries off Cape Cod, well north of the hurricane zone, is that hurricanes generally skirt Barbados. It just rains a lot there in late summer. But then it has been cascading down, causing appalling floods, in Switzerland, where Lady Thatcher used to take her hols.
What unsettles the oil market is that hurricanes have a nasty way of getting into the Gulf, where there are umpteen refineries at risk as well as the offshore rigs. The Saudis, who fear even $50 a barrel for crude for any length of time will do the world economy no good - and threaten future demand for oil - blame lack of refinery capacity for the $66 barrel.
Their logic is slender. Naturally, oil dealers in New York get excited when US stocks of refined products - petrol and heating oil - run low. But unless those shortages are caused by lack of crude arriving to be refined, they are not a reason for bidding up the price of crude for immediate delivery.
Very possibly some country somewhere is building up its stock of crude against a rainy day. There have been reports of both the US and China doing just that.
Futures prices are another matter. They are driven by perceptions of what is going to happen next - and there is no comfort to take from events in Iraq, still less from the ominous failure of either Eurodiplomacy or American bluster to check Iran's atomic programme.
A lot has to go right with the world before we can sensibly look for cheaper oil. All you can do is admire the impact of Shell and BP shares on the Footsie, pay up at the pump and hope that so much tax money is tumbling into Mr Brown's coffers that he won't have to raise other taxes.