The unexpected heat wave affecting London this week has created a greenhouse effect that sent temperatures around the pool deck and in the stands soaring to more than 30 degrees Celsius (85 Fahrenheit).
At a coaches meeting Thursday, organizers announced they were working with air conditioning units to get the pool deck temperature down to 27 degrees Celsius (80 Fahrenheit).
"They have some problem with the climate control equipment," FINA executive director Cornel Marculescu told The Associated Press. "It could be a problem for fans and journalists also. LOCOG had a test event here in March but they probably weren't expecting this kind of heat."
Canada coach Pierre Lafontaine was among those raising concerns during the meeting, which was closed to the media, saying that his athletes have been affected.
"The organizers are doing a great job dealing with it," Lafontaine said in an email to the AP. "It is much better today already."
There are also milder concerns over the water temperature, which should be between 25 and 28 degrees Celsius (77-82 Fahrenheit) according to FINA rules.
Cooler outdoor temperatures forecast over the next week could also relieve the stifling conditions.
"It shouldn't be a problem then," Marculescu said.
After weeks of miserable weather, the sun has shone brightly on London this week, and temperatures have soared to near 30 degrees Celsius (85 Fahrenheit).
When the Zaha Hadid-designed Aquatics Centre fills to its capacity of 17,500 people on the opening day of competition Saturday, the temperature will probably rise a few degrees.
The London organizing committee (LOCOG) has sent heat warnings to people with tickets to aquatics sports, urging them among other things to dress appropriately, and to help themselves from the water coolers scattered around the venue.
Spectators also "are reminded through public announcements to stay hydrated and be aware of their body temperature," the committee said in a statement.