The changeable UK weather can have a significant impact on retailer performance. When the weather changes, retailers risk losing millions through low stock levels, empty shelves and disappointed customers. It can lead to unexpected fluctuations in store footfall and sales, shortages in availability, and impact on the costs and efficiencies of the whole supply chain - this is particularly true for fresh, chilled and seasonal products. On-shelf product availability matters - if the UK food grocery sector had 100 per cent availability all the time it would be worth an additional £1.1 billion. Customer loyalty can also be improved - as customers that cannot buy their favourite product three times in succession are likely to change where they shop.