Fabulous frocks and heavenly hats will be on display for Ladies' Day at Royal Ascot today.
But fashionistas will be hoping that nothing rains on their parade, with downpours forecast for the social season highlight.
This year's dress code has been tightened up, with a team of assistants handing out pashmina-style shawls and fascinators to those breaching the regulations - which now stipulate that bare shoulders and thin straps are a no-no, with hats or headpieces mandatory for all racegoers.
It may well be that umbrellas and ponchos are this year's must-have accessories however, with showers due at the Berkshire racetrack throughout the day.
The Queen may even need to shelter from the weather, as a thunder storm is forecast for 2pm - the precise moment she is due to make her way down the racecourse in the traditional horse-drawn carriage procession.
Matt Dobson, a forecaster with MeteoGroup, the weather division of the Press Association, said: "There will be pretty heavy rain first thing, turning murky and muggy by the late morning. In the afternoon, there is the risk of heavy downpours.
"If they get unlucky, there could be an absolute cloudburst. By 2pm there could well be thundery conditions."
Ladies' Day is known for the extravagant creations on display - with women trying to outdo each other in the fashion stakes.
Racegoers were sent copies of a style guide ahead of the five-day meet, after the new dress code was announced in January.
In the royal enclosure, fascinators are no longer deemed acceptable, with hats compulsory. A hat, fascinator or headpiece must be worn in the less formal grandstand area.
All women are expected to wear skirts or dresses of "modest length", according to the new guidelines, with their midriff covered.
Men now have to wear a suit and tie in the grandstand and black or grey morning dress in the royal enclosure.
About 300,000 people are expected to attend Royal Ascot - now in its 301st year - consuming some 170,000 bottles of champagne, 10,000 lobsters, 5,000 oysters and 18,000 punnets of strawberries.