That figure is expected to rise to 8.4m by 2008, partly thanks to the knock-on effects of the Sydney Olympics, which should boost numbers for several years to come.
The state-funded Met Office, which bills itself as "one of the top two national weather services in the world, " is in overdrive, sending extra weather balloons into the atmosphere to try to get a read on what's to come and providing daily updates to government officials and other Olympics honchos.