With less than 24 hours to go, grey storm clouds are gathering over what until the last few days was looking set to be one of the most meteorologically blessed Royal Weddings in history.
After near-record early April temperatures, the warm, dry south-easterly airflow over southern Britain has swivelled around to a chillier north-east.
Although it won’t be cold - temperatures in London tomorrow should reach a respectable 16-19C - it might be overcast, with a stiff breeze and, worst of all, there is a 30 per cent risk of heavy showers.
Having subjected everything else to such meticulous planning, organisers of the wedding may be wishing they could interfere with nature and use science to ensure clear blue skies over London.
An impossible dream? Not necessarily. This has, after all, been attempted before elsewhere.
Seven years ago, for instance, a Russian company called the Atmospheric Technologies Agency was hired, at a cost of £20,000, to sprinkle several tonnes of dry ice into the clouds over St Petersburg, before a huge open-air concert by Paul McCartney.
The aim was to disperse the big cumulus clouds which had been building up over the city - a technique known as ‘overseeding’, in which the ice causes the water in the cloud to coalesce into tiny droplets too light to fall as rain.
The Russians are big fans of ‘weather control’ - the harnessing of technology to modify the pattern of clouds and, in particular, rainfall.
As well as being ‘seeded’ to try to stop rain, clouds can also be treated with chemicals to make them produce rain. Scientists can also intervene to make rain fall in one place and not another, to tackle droughts and try to avert floods.
Indeed, the savvy Russians boast that it has not rained on a Moscow May Day parade for decades.
