Britain’s gentle weather made us who we are. Is it all over now?

In the opening lines of his Canterbury Tales, Geoffrey Chaucer confidently declares: “In April the sweet showers fall, and pierce the drought of March to the root.” How things have changed: these days, who can characterise a whole month in terms of a single form of weather?

Gone is the gentle predictability of a summer with moderate showers and balmy evenings. The Met Office has announced that Britain can look forward to a schizophrenic season of soaring temperatures and swamping downpours. And when this biblical summer finally gives way to autumn and winter, the UK faces a risk of “unprecedented” rain and floods. If this lasts, tepid moderation will no longer be our weather’s forte, and our climate will be more akin to the sentiments of Oscar Wilde than Chaucer: “Nothing succeeds like excess.”

The consequences of these increasingly extreme and changeable times could go far beyond getting caught short without an obliging brolly, or spending a few more afternoons sautéing under unexpected rays. It could challenge our country’s very essence.

Our climate has played a decisive role in moulding the traditions and frameworks that structure our lives. Long school holidays in the summer are a relic of the weather’s influence in bygone times. Children were needed to pick fruit and help farm the land during the summer months, and long breaks from school were created to accommodate this. Seasonal changes have also given birth to some of our most enduring celebrations. Thousands of us still dance round the maypole on May Day, and many Christmas festivities have their root in ancient celebrations of the winter solstice. In his study of Englishness, Harry Mount has suggested that our climate has influenced the sports we play, the buildings we design, even our temperament.

The fingerprints our climate have left aren’t just a quaint artefact of history. The calendar of our seasons influences our personal diaries even today. Anyone over the age of 25 will now be experiencing the relentless onslaught of nuptials that spring and summer brings. The expectation of dry, long days also gives way to socialising al fresco – picnics in the park and lazy gin and tonics in the garden – while the frost of winter buffets us into the warm embrace of our homes.

A change in seasons sees the food we buy morph from stodgy warming pies and puddings to crisp salads and smoky barbecued joints; our mulled beverages dwindle and are replaced by the clink of chilled glasses. One report has suggested that if temperatures rise above 64F (18C) in the UK, the demand in supermarkets for fizzy drinks increases by 22 per cent. How will shops manage in August if we’re craving a warming Bovril one minute and an icy lemonade the next? Stock management will become a thing of alchemy.

There’s the biannual wardrobe swap to think of too. Deciding when to migrate the 18,000-denier tights and woolly polo-necks into under-thebed storage to make space for light cottons is hard enough as it is (my March timetable this year was a freezing mistake).

So if the moderate weather of our past and present has made we Brits who we are today, what will more extreme weather do to us in the future? Let’s hope its influence is confined to the quality of our raincoats rather than the volatility of our temperaments.

follow Verity Ryan on Twitter @Veritygryan; read more at telegraph.co.uk/opinion