"Everyone lives by selling something," according to Robert Louis Stevenson. And how much he sells, when he sells it, and even how he sells it, are often related to the weather. Our buying habits are influenced by the elements, and respond to changes in both temperature and rainfall.
Not unexpectedly, studies indicate that in general the volume of goods sold in large department stores falls during periods of wet weather, and increases again when the weather becomes good.
The sales-to-rain relationship is a complex one, however, and shows subtle variations with the time of year. Surprisingly, for example (until you think about it), higher-than-average sales are associated with wet conditions around this time of year, in the late spring and early summer.
But in general shoppers find the rain discouraging. A comprehensive study carried out some years ago in the US found that when the weather is clear and bright, business is enhanced by an average of 3 per cent; on wet days, by contrast, average takings are 7 per cent or more below par. The difference between blue skies and stormy ones, therefore, turns out to be something like 10 per cent of normal turnover.
But the duration of the rain, the study says, is the biggest factor in determining the effect on would-be shoppers. With three hours or less of drizzle, the volume of sales slips by 5 per cent; with four to six hours of rain, the deficit rises to 9 per cent of normal turnover; and on a day that turns out to be a complete washout, sales drop on average by a full 15 per cent.
The heaviness of the downpour, strangely enough, appears to be of little consequence: a heavy thundery shower lasting only for an hour or so is much less inhibiting to business than a fraction of the equivalent rainfall spread over the whole day.
The timing of the rainfall, however, is important. Sales are very vulnerable when the rain occurs in the morning, but are less so when only the afternoon is wet. As the study says, and here I quote verbatim lest I be accused of being non-PC: "Once the city shopper is on her way, she becomes a captive customer."
Rain on a Monday, too, it seems, has less effect on sales than rain on other weekdays, and Saturday shoppers are the most resilient of all; suggesting, as one might indeed expect, that those whose shopping time is limited to that day are less daunted than others by the prospect of a wetting.