Michael McCarthy: A summer this wet and windy just isn't natural

I once arrived in Finland on May Day. As I walked into my Helsinki hotel, a big Finnish bloke attacked me. Luckily, it was with a balloon. However, the fear flashed through my panicking brain that even though he was not a gunman or a knifeman, merely a balloonman, he still meant to do me harm, and it was with some difficulty that I extricated myself – only to find that everyone in the whole damn city was in the same damn state. They were all pie-eyed. I'd never seen anything like it.

May Day in Finland is a labour festival and a student festival – the students all wear the white hat they get when they leave secondary school, the ylioppilashattu (I wrote it down at the time, if you want to know) – but that doesn't explain the truly Bacchic fervour, the ecstasy almost, with which the First of May is greeted and celebrated.

To understand it you have to understand about the Finnish winter. In January, say, because of the latitude on which it sits – above 60 degrees north, up there with the Shetlands – it is light in Helsinki from about 9am to 3pm. Bad enough. Sometimes though, it is cloudy all day, and sometimes, because of a phenomenon known as a temperature inversion, the cloud can sit there for days and days, a week, two weeks, even (exceptionally) for a month.

Can you imagine going about your business for a month without seeing the sun? No wonder the Finns have one of the world's highest suicide rates, topping themselves, as John Cleese once put it, at a rate of knots. No wonder they greet the coming of the new season of blue skies and warm days with an elation that borders on frenzy. Even with drinks the price they are in Finland.

It may be an exaggeration to say that this August has felt like January in Helsinki, but it isn't much of a one. Later this week, the UK Met Office will release its sunshine and rainfall and wind figures for the month, and statistics will confirm most people's impression that this has been one of the dullest, wettest and windiest Augusts on record, putting the tin hat on what has been a pretty lousy summer anyway.

There are reasons for it, of course, the principal one being the jetstream, the fast-moving high-level ribbon of air which circles the globe at the boundary between the cold polar air to the north and the warm tropical air to the south, and which is responsible for steering areas of low pressure across the Atlantic. This year it has moved south of its normal course – just as it did last year, in fact – so many more of the Atlantic depressions than normal have been directly crossing the British Isles and bestowing upon us their gales and downpours and murk.

And in turn, there are reasons for the jetstream moving south, although these are less well understood, the main one being the influence of La Nina, the cooling of the central and eastern Pacific Ocean which happens every few years and affects weather systems across the globe. As the current La Nina fades, the jetstream will probably move back further north.

But knowing all that somehow doesn't compensate, does it? It doesn't make up for the lost summer, the absence of crystal mornings, and hazy, lazy days, and long glowing evenings (my own particular beef being that, furthermore, this has been The Summer Of No Butterflies).

And I think the reason is, we have age-old instinctive rhythms in us which manifest themselves almost as sense of entitlement, which is enshrined in folklore and poetry.

"As the sun sets, it also rises."

"If winter comes, can spring be far behind?"

We bear with the dark season because we know the season of light will follow. We know it. We may not be entitled to much in this life, but everyone of us gets a hot season after the cold, and in Finland, they shout for joy. The balmy time always arrives.

But what if it doesn't? Then we're helpless. As Mark Twain said, everybody talks about the weather, but nobody ever does anything about it.

I don't know about you, but it leaves me with a gnawing sense of dissatisfaction with things, a pervasive irritability, in these dog-days of August, at the end of this non-summer. Don't push me, OK? I'm on a hair trigger. I can snap at any second. Give me plenty of space. You should know that I am armed.

All right, it's only with a balloon. But I'm not afraid to use it.