Not many years ago, when driving the cab around London looking for a fare, you could tell the American tourist by the gentleman’s white gabardine raincoat, either worn or draped across his left arm.

Now climate change has made summer in the capital drier and with advanced technology, making forecasting more accurate.

Back in the day, we had countdowns for sending a rocket to the moon; listening to the pips on the talking clock, and counting down the seconds up to the New Year.

We didn’t get a countdown to the weather, just Michael Fish reassuring the viewers that the woman who phoned to say it was getting a bit breezy outside, or the BBC weather girl suggesting you bring an umbrella with you tomorrow.

No. I’m talking about American weather, this is the country that has its own dedicated television weather channel (in my opinion the most entertaining station to watch when holidaying with our colonial cousins).

Those clever people at Apple have updated their weather app. Living in a country like Britain, where the weather is a near-national obsession and changes within the course of an hour, here we would say it’s pi**ing down, but the Americans frequently use the word precipitation.

And this is where the weather app comes in. Now I know to the minute when rain – sorry, precipitation – will fall.

Beyond telling you to bring an umbrella or sunglasses the graphics include wind, UV index and barometric pressure. Alongside this, you now get full-screen weather maps, high-resolution images that animate the progress of rain and clouds, air quality, and temperature — sort of like your own personal weather assistant.

Or you could go with the tried and tested looking out of the window before leaving home.