Can you really predict snowfall from August fogs? No, studies suggest

Weather folklore can be vague, but the saying that the number of August fogs matches the number of snowfalls the following winter is rather precise. In some parts of the US people put beans in a jar to keep count of the fogs so they know how much snow to expect.

The devil is in the detail though. Is the morning really foggy, or just misty? How many flakes make a snowfall? Subjective interpretation gives wriggle room to make the prediction fit.

Meteorologists with stricter definitions of fog and snowfall can make a fuller assessment. A weather team in Memphis found 11 days of fog in August 2017 followed by four days of snow in winter. The next year saw five foggy days in August followed by seven snows.

Similar studies in other areas have failed to show any connection. This applies even in places where the average number of August fogs roughly matches the average number of snowy days, such as Roanoke, Virginia. As one would expect, both numbers shift chaotically with no correlation in their rise and fall.

However, folklore is not easily dispelled by such myth busting. With a little creative interpretation and the magic of confirmation bias – remembering only when the formula worked – the belief is likely to persist.