The prospect of the Windy City becoming the Rainy City tomorrow – likely, according to the weather forecasters – means that Paula Radcliffe is facing an uphill struggle in her quest for a marathon world best time, even on the flat streets of a city that boasts the fastest 26.2 miles course on the planet.
Accordingly, as Britain's favourite athlete of the moment prepares to round off her annus mirabilis with victory in the La Salle Chicago marathon, her focus is narrowing upon the result.
Not that that can be taken for granted, given the presence in the field of the 29-year-old Kenyan runner who set the current world best of 2hr 18min 47sec in winning this event last year, Catherine Ndereba.
After Ndereba had become the second women runner under 2hr 20min just a week after Japan's Naoko Takahashi had broken through the barrier, the race organisers named her 'Catherine the Great'. 'Paula the Magnificent' doesn't have quite the same ring, but officials could be racking their brains for a suitable soubriquet if the 28-year-old Bedford athlete's race goes according to plan.
"There are lots of expectations from everybody – but then again I put a lot of expectations on myself," Radcliffe said. "It's very important to finish the year with a good race. It's a fast and sheltered course. I don't mind if it's cold. I don't mind running even in snow. But for the spectators' sake I hope it doesn't rain and isn't too cold. Whatever happens, it's the same for everyone and isn't going to affect the actual race."
Six months after winning her debut marathon in London in a time just nine seconds outside Ndereba's record, Radcliffe is fine tuning her approach for a challenge that will have one very significant difference – this time she will be running alongside men.
"It's going to be difficult with men in the race trying to go off at my own pace and not being tempted to go with them," said Radcliffe, who twice achieved the major gold she has so long sought on the track this season in winning Commonwealth and European 10,000m titles. "We'll see how the race develops – but it's part of my natural style to run hard. Winning the race is what it's all about."
That task will be complicated not just by the presence of Ndereba, but also Deena Drossin, the American who finished runner-up to Radcliffe as she retained her world cross-country title earlier this year, as well as London runner-up Svetlana Zakharova and Japan's new find Yoko Shubui.
The prize for the victor in Chicago's 25th anniversary event is the richest offered by any marathon, £64,000. Should anyone run a world best, there is an additional £96,000 on offer, plus a car.
"It will be a very fast race to watch," said Ndereba. "I know I can do all things. I cannot put a limit on myself. I think Paula ran a very good race in London and I respect her because of her outstanding career. But I compare everybody as a strong challenger. As you saw last year in the men's race here, everybody was watching each other and Ben Kimondio, the pacemaker, just kept going and ended up winning."
The man whom Kimondio surprisingly beat on that occasion, fellow Kenyan Paul Tergat, will be seeking to put things right tomorrow. But Tergat, the second fastest marathon runner in history, faces a tough challenge against the man who bettered his own world best in winning in London this year, Khalid Khannouchi, who is seeking a fourth Chicago title.