July starts cool – when will it warm up?

A cool start to July

After a cooler than average June, July has continued in the same vein, with mean temperatures around 1-3C lower than average so far this week. When combined with brisk winds and outbreaks of rain, it’s felt more like autumn than the second month of meteorological summer.

In fact, this morning, there was a fresh covering of snow on the peaks of the Scottish mountains. Whilst not exceptional for early July, it’s certainly unusual. Visually, it looked out of place against the lush summer green foliage in the mountain valleys below.

Why so unsettled?

The reason for the autumnal feel to our weather at the moment is an unseasonably powerful jet stream 30,000 feet above the Atlantic Ocean. It has been moving at a speed of around 180mph (red and pink in graphic below) – something more akin to what we’d expect in autumn and winter.

This powerful jet stream has been developing and then catapulting areas of low pressure our way – bringing cloud, rain, brisk winds and cool air. Wind gusts in northern parts of the UK today are expected to be unseasonably strong, reaching 40-50mph around some coasts and hills.

Is it going to warm up soon?

After a cool start to July, no doubt some will be wondering if it is going to turn warmer anytime soon. There are signs that slightly warmer air will arrive early next week. However, at best, it’s only going to lift temperatures to around average – the high teens Celsius in the north and low 20s in the south.

Despite temperatures being higher, it’s going to stay unsettled next week, with showers or longer spells of rain at times. So, even though it may technically be warmer, unless the sun is out – which it won’t always be – it may not feel vastly different to this week.

What about the rest of summer?

Summer is a notoriously tricky time to predict the weather far in advance. Changes in the jet stream and weather patterns can happen much more slowly at this time of year. This significantly reduces predictability beyond a few weeks at most.

Additionally, as Atlantic hurricane activity typically increases further into summer, this can bring even more uncertainty to the weather forecast. Powerful hurricanes can significantly influence the position of the jet stream, which in turn can affect our weather down the line. However, any such influence may not start to become apparent more than a week in advance.

So, for now, we find ourselves stuck with the status quo, with no return to notable summer heat expected anytime soon.