Total Scottish retail sales were 0.1% up on May 2011, when they had fallen 1.1%, according to the latest Scottish Sales Monitor for May.
Like-for-like sales were 1.2% lower than a year ago, when they had fallen 3.2%.
Food sales rose above their year-earlier level but, once food inflation is taken in to consideration, volumes are likely to have fallen slightly. Warm weather at the end of the month helped boost sales of summer foods.
Clothing and footwear sales were also helped by warmer weather, without this there would have been an even larger decline in non-food sales.
On both like-for-like and total measures, sales were much weaker than for the whole UK. This was the fourteenth month in a row that UK sales growth exceeded that in Scotland.
Ian Shearer, Scottish Retail Consortium (SRC) director, said: “A welcome spell of warmth at the end of May helped lift these figures but the burst of summer didn’t bring a boost on the scale enjoyed elsewhere.
“The underlying picture remains weak, showing sales falling in real terms for the sector overall, and this is particularly worrying given that they are being compared against poor figures for May in 2011. Consumer caution persisted, household budgets are still under severe strain and most shoppers are committed to buying only what they consider to be essentials.
“Food retailers had a brighter month with changes in consumer preferences reflecting the shift in temperatures. Demand for roasting joints and soups turned into sales of salad and barbecue meats for the final week.
“Other stores, with supplies of summer fashions, outdoor leisure gear and gardening equipment currently languishing in stockrooms, badly need a more prolonged period of summer weather in the coming months to begin to ease the gloom.”