A report published today by the British Retail Consortium, based on Met Office analysis of weather data, suggests that warmer weather in September could cost non-food retailers £80m per week.

The report, “Weather to Shop?”, indicates that temperature can have a significant influence on how much we spend on retail goods - but only at certain times of the year.

Met Office analysts compared BRC retail sales data with weekly temperature data and found that there was a clear relationship between temperature and increases in retail sales.

Its impact is strongest from mid-August to early October, where warmer weather delays the purchase of Autumn-Winter ranges. Over that period, for each degree warmer it is than the previous year, growth in sales is reduced by 1.1%, equivalent to around £40m per week.

This Summer has seen temperatures on average 2.0oC higher. If that trend continues into September non-food retailers will see sales £80m per week lower than they would have been otherwise.

In the long run, sales lost to unseasonable weather are largely recovered, once temperatures normalise; meaning that temperature fluctuations are not behind the downward trend in growth of non-food sales that we have seen since 2014.

However, warmer weather during the transition to Autumn can have a lasting effect on individual retailers. Both because it causes a shift in the type of non-food products bought and because weaker sales at the beginning of the season leads to more stock being sold at a discount later in the season, reducing profitability.

The study found that the relationship between sales and the temperature changes over the year. At certain times of year, such as in the Spring, warmer weather can help sales. At other times it can hinder them; while at sometimes of year, such as Christmas, factors other than temperature drive sales growth.

Impacts also differ across product categories. Clothing and footwear sales are particularly negatively affected by warmer temperatures in the Autumn, while women’s (but not men’s) clothing sales are boosted by higher temperatures in the Spring. Sales of furniture and home textiles benefit from cooler weather in the summer but are little affected by changes in temperature during the Winter.

Understanding the impact of the weather is crucial for retailers. While the weather cannot be controlled retailers need to be prepared to respond to unexpected weather patterns in their stocking decisions and marketing activities.

Rachel Lund, BRC Head of Insight and Analytics, said:

“While few in the retail industry would deny that the weather impacts how we shop, the fact that this study reveals that its impact can be large and changeable only serves to highlight some of the complexity retailers have to navigate in serving consumers. The ability to understand and respond to unseasonable weather is clearly crucial for retailers wanting to thrive in today’s extremely competitive retail market.

"However, we should also bear in mind that the weather does not shift long term underlying sales trends. Inflation has eaten into households’ budgets over the last two years, pushing spending towards essentials and away from discretionary items. That has particularly impacted Non-Food spending:  we’re forecasting that Non-Food sales will grow just 0.1 per cent overall in 2018, with the total market growing 1.5 per cent -  well below the 10-year average of 2.1 per cent. The reality is that the retail environment is likely to remain very challenging for some time to come."

Malcolm Lee, Weather Analytics Manager for the Met Office, said: 

“Analyses of this type can’t predict ‘boom or bust’ for the high street based on our weather forecasts, but can offer business insight into how weather has impacted on sales in previous years.

“This research shows that for certain product lines at certain times of year, sales growth is strongly influenced by the weather. However, there is much less evidence that total sales are impacted over the season as a whole; it is the profile of the spend in the season (such as early or late season shopping) that the weather impacts most strongly. This research enables weather intelligence to be used much more effectively in managing a retail business.”

An executive summary is here.