The Umbrella That Waits Until It Is Sure the Rain Is Real

Picture a high street just after lunch. A few fat drops land on the pavement, a man in a green coat looks up at the sky, and all around him umbrellas bloom open like startled flowers. All except one. His umbrella stays neatly furled, humming quietly to itself, considering the evidence.

This is the Considered Umbrella, a folding model in navy canvas with a polished wooden handle and a small sensor in the tip. Its makers, a two-person workshop that describes itself as weather sceptics, believe the modern umbrella opens far too easily. One stray drop from a gutter, one sneeze from a passing dog, and up it goes. The Considered Umbrella, they promise, will never be fooled.

How it makes up its mind

The sensor counts the drops landing on the tip, measures their size and checks the sky for clouds of a suitably serious colour. If the rain keeps up for four full minutes, the umbrella opens with a slow, dignified sigh. If the drops stop before then, it announces, in a calm voice, that this was merely a passing mood of the weather and not worth troubling the canopy for.

Early owners report mixed results. One commuter says she has stayed perfectly dry for a whole autumn, mainly because she now stands in shop doorways for four minutes every time it spits. Another reports that his umbrella finally opened on the doorstep of his own home, at the exact moment the sun came out, and then took eleven minutes to close because it wanted to be sure the sun was real as well. The workshop says this is the umbrella working as designed, and it has added a small rainbow sticker to the box.

A deluxe version will be offered next spring. It refuses to open at all unless the forecast that morning promised rain, on the grounds that it does not wish to encourage unscheduled weather.

The real idea behind it

The joke rests on something most of us do every day: trying to guess whether a few drops are the start of a real shower. Weather forecasts help, but their most famous number is widely misunderstood. A forecast of a 40 per cent chance of rain does not mean it will rain for 40 per cent of the day, or over 40 per cent of the town. It means that at any one place in the forecast area there is a 40 in 100 chance of at least a little measurable rain during that period.

So a low percentage is not a promise of a dry afternoon, only a smaller chance of a wet one, and a small shower can pass over one street and miss the next. That is why the sensible answer is the one people worked out long before sensors: carry the umbrella anyway, and open it the moment you feel wet.