Why the Scottish summer has been such a washout so far – and whether the weather will brighten up

Inimitable Western Isles meteorologist Dr Eddy Graham reported resorting to double gloves and winter gear on a bike ride recently – a testament to the summer’s frosty chill. Stornoway itself has had its spirits dampened, recording the dullest June in 95 years of local records.

Three questions dominate conversations these days: Why is the weather so bad? What about global warming? And when will it get better?

On the first question, the culprit in large part lies high above our heads. The jet stream, a fast-moving, high-altitude ribbon of air, acts like a meandering motorway. Transporting weather systems, this is what brings us most of our rain, wind and other weather.

How climate change – and less water – is impacting Scotland

The jet stream’s current position is steering low-pressure systems across the Atlantic towards Scotland, influencing prevailing winds and bringing somewhat cooler air than usual. The meanders of the jet stream can also trap air masses, leading to prolonged stretches of hot or cold weather.

Global warming also plays a role in altering our weather patterns. Met Office data reveals a trend of rising summer temperatures in Scotland. I appreciate that doesn’t give much solace to fellow Scots who have been forced to turn their heating back on, so hear me out.

Think of it like your wardrobe. What you wear changes day-to-day, but your overall clothing collection reflects the local climate throughout the year. So, while the long-term trend is towards rising temperatures, there will be periods where this doesn’t hold true.

Impacts of climate change

That said, ongoing global warming also has a wider and more profound impact on our weather in Scotland. As the Earth warms, this extra heat increases the energy stored in the atmosphere, providing fuel for more intense weather systems. This can also disrupt the jet stream, causing it to meander more, becoming less predictable and steering weather systems in unusual directions. In addition, warmer air holds more moisture. For Scotland, this doesn’t necessarily translate to consistent rainfall, but rather more instances of intense downpours like we saw in June after a very dry May for many.

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Interestingly, Scotland’s north-east coast seems to have been the sweet spot this June by experiencing drier weather and closer-to-average temperatures. Geography plays a significant role in shaping local weather conditions. Mountainous regions such as the north-west Highlands and Cairngorms cause a ‘rain shadowing’ effect, shielding the east from the worst of incoming Atlantic weather systems. As air rises and cools over mountains, it condenses and releases moisture, leading to drier, warmer conditions in north-easterly areas.

This summer’s weather whiplash serves as a reminder that Scotland’s climate is inherently changeable. While a single season doesn’t definitively signal climate change, the trend towards more extreme weather events should be a wake-up call for decision-makers.

In Edinburgh and the Lothians, rainfall in May was more than twice the average amount for this time of year, bringing overwhelmed drainage systems and localised flooding. We desperately need to adapt our services and infrastructure, recognising that this type of weather is here to stay.

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Back to the here and now, and I’m sorry to say that the immediate future doesn’t hold much promise. The next week or so seems like a continuation of the current miserable and wet conditions we’ve become used to so far this summer.

Long-range forecasts are difficult at this time of year, but there is a glimmer of hope in the predicted jet stream position in the next couple of weeks. This will hopefully lead us to slightly more settled and warmer weather, but no promises on that from me.

Let’s not lose the spirit of Billy Connolly’s saying. While I won’t be packing away my raincoat just yet, there’s still plenty to enjoy in Scotland, whatever the weather.

George Gunn is a research associate at the University of the Highlands and Islands, a local government officer and consultant