You know, British summers are like buses. You wait ages, and then three come along at once - confusing a nation of shoppers who haven't experienced a bus for years. OK, maybe summers aren't that much like buses.

The point is, while we love summer, we've gone so long without it that we were totally unprepared this year. And the same goes for high street stores, who've had to think on their feet and reorganise stock as a result of the atypical weather.

If you've bought an August fashion magazine and started lusting after autumn collections, you may find some items aren't in stock as promised. We'd generally expect summer sales to have wrapped up and everyone to be in full-blown autumn planning mode by now - but with demand continuing for the summer sale stock, autumn's having to wait its turn.

'Remember when it was snowing in April?' says Jane Shepherdson, CEO of Whistles. 'After a bad start to the year, retailers expected the sale to clear all the beautiful summer stock that no one would ever have the chance to wear. Normally sale is fast and everyone looks forward to the new season ahead.'

By the end of July, retailers would usually have moved any remaining pieces from the spring/summer collections to the back of stores to make room for autumn clothing. This year has been a different story. Clearing out summer stock while the UK was still enjoying temperatures in the high twenties and low thirties would make no sense. While the weather's still good, we don't want to walk into a store and see only rails of autumn coats and knitwear - this year, we've needed serious amounts of summer clothing - so you'll find that many shops still have their sale stock front and centre, and prominently displayed online, even if the choice is dwindling.

In previous seasons, says Shepherdson, the Whistles sale has mostly been shopped by younger customers. This summer has seen a different dynamic. 'Many of our customers are shopping sale and new season at once, looking for solutions of what to wear now. Customers may start their AW13 shopping now but they want to know how they can wear those pieces with a nod to the warm weather. The wear-now and wear-later mentality is something that people are starting to consider seriously.'

In other words, clever shoppers are looking for those versatile summer pieces that can be layered up when it gets cold, or those lightweight autumn pieces that work well with bare legs and arms. After years of complaining about drizzly, chilly weather, we thought a long, beautiful summer would be a fashion no-brainer. Instead, August is shaping up to be something of a puzzle: how to shop for more heat when the summer stock is disappearing before our eyes.