Is winter air really heavier than summer air?

Is winter air heavier than summer air? Of the various time honoured sailing debates, the link between wind strength and temperature is one that is frequently contested between those that understand how their boats feel and those that understand the science behind it.

But for all the technical experts that have tried to dispel the view that there is a difference, it is hard to ignore the comments of the world’s most experienced sailors. Shortly after finishing Leg 1 of the Volvo Ocean Race Camper’s skipper Chris Nicholson was describing the brutal conditions that his team had endured on the last night of the leg and comparing them to the start of the race, a similarly boisterous 24 hours.

“It was a Southern Ocean 40 knots as opposed to the 40 knots in the Med,” he told me. “On the last night into Cape Town we had a storm jib and three reefs in the mainsail as opposed to two reefs and a J4 headsail on the first night in the Med.”

To highlight the difference his team cut a short video for us showing Southern Ocean versus Med. Can you spot the difference?

For those of us that are still out on the water over the winter, next month’s Performance World (Feb 12 issue out Thursday 12 Jan) asks what is the technical explanation and is there any way that we can quantify and utilise the findings to help us exploit the colder conditions.

Andy Claughton of Southampton University’s renowned Wolfson Unit explains the theory and suggests what it means in practice.