Weather in the UK in July

If tbe weather turns chilly you have a good excuse to buy a nice wool sweater.

Seriously, no one knows till August. You can look at average temperatures in the areas you’re visiting for the last few Julys, but our weather is changeable in the extreme. As a maritime nation in the centre of several weather systems, our weather is changeable but also moderate. It could be warm & sunny, rainy with chilly winds, almost anything except we rarely get the extreme inland heat that certain parts of the US and Europe get in July. There’s usually a flicker of breeze.

Bring a lightweight waterproof jacket and some thin layers.

But, I keep hearing that it's getting 'hot' in the UK with what seems more like weather here in the US.

The climate in the US ranges from the hot humidity of Florida to the cold, wet of the Pacific Northwest and everything in between. The UK is a nation of averages, nothing extreme. July should be pleasant but no-one can guarantee anything.

Remember - to have an average, you have to live the extremes. It is hard to predict beyond seasonal averages. We have hit some very hot spells in the UK but do not remember any unusually cold spells. I don't think you freeze the whole time. Just pack one medium weight sweater with a quality windbreaker jacket. Evenings can be cool.

I use wunderground.com to see actual day-by-day temperatures going back more years than I try to check. I don't dress for averages. I dress for how cold it might be when I head out of the hotel in the morning on each particular day, and how cold it might be when I'm out at night. I've linked to London's weather for July 2017. You should be able to find stats for somewhere near the Outer Hebrides if not actually on them. Choose "History" then "Monthly", adjust the month/year, and scroll down when the screen re-paints. Definitely check multiple years, especially for the northern locations, to get a clearer idea about the range of what you may experience.

During a long visit to northern France, southern England and Wales last summer, I learned that it was prudent to carry my (hooded) rain jacket with me every day, because the sky usually ended up looking threatening at some point. I seldom actually got rained on, which went a long way toward keeping me comfortably warm.

I packed a pair of lightweight polypropylene long johns and wore them most days. I figured why not? I walked a lot but wasn't doing heavy hiking. My outer warm layer was a relatively light fleece jacket, then I had the waterproof jacket, which also served as a windbreaker. In retrospect, I should have paid more for a vented jacket with Goretex or an equivalent product, because I was sometimes sweaty when I had the jacket zipped up.

Bring layers and be open to by something if need be. We were there in July last year and hit a heat wave that had us sweating and looking for a pool. We have been there when we needed to wear a jacket. Looking at the forecast closer to when you will be leaving is helpful but I say bring layers

Feeling cold depends on more than air temperature. Wind (as in wind chill) and humidity affects your comfort as damp and windy conditions extract more body heat than dry and still conditions. Having a good wind shell and protecting extremities adds a lot to your comfort in cool weather. And as previously noted, if you under pack, you can buy a nice souvenir wool sweater.

Northern Scotland Climate data: https://www.metoffice.gov.uk/climate/uk/regional-climates/ns

July or August is the warmest month, with mean daily maximum
temperatures at low levels around 19 °C in areas close to the Moray
Firth. Elsewhere in northern Scotland the mean daily maxima are
somewhat lower, and are less than 16 °C over the higher ground and the
islands. Extreme maximum temperatures can occur in July or August, and
are usually associated with heat-waves. On the larger Western Isles
and in sheltered places, temperatures can exceed 28 °C. For example,
32.1 °C was recorded at Onich (Highland) on 1 August 1995. In contrast, over Shetland high maxima are not achieved and the
record is
only 25 °C, set at Baltasound on 2 July 1958.

Southwest England Climate: https://www.metoffice.gov.uk/climate/uk/regional-climates/sw

The south-west peninsula forms the most southerly part of the British
Isles. The sea which surrounds the area on three sides has the highest
annual mean temperature of any sea area near to the UK, close to 11 to
12 °C. With winds mainly blowing from the sea the annual mean
temperatures are close to this in coastal areas of Cornwall and the
Scillies. Compare this with the lowest UK annual mean temperature for
low lying areas of about 7 °C in the Shetland Isles. The annual mean
temperature tends to fall towards the north east where 10.5 °C would
be more typical around Bristol.

July and August are the warmest months in the region with mean daily
maxima ranging from around 19 °C in coastal Cornwall to 21.5 °C in
inland areas of Somerset and around Exeter. This is to be compared
with 23.5 °C that is typical of the area of highest UK temperature
around London. Instances of extreme high temperatures are rare and are
associated with hot air brought from mainland Europe on south easterly
winds accompanied by strong sunshine. Records include 35.4 °C at
Saunton Sands, a site which is next to a large dune/heath area in
north Devon, and 34.5 °C at Yeovilton in Somerset, both on 3 August
1990. The highest UK temperature stands at 38.5 °C at Faversham (Kent) on 10 August 2003.

The hottest ever temperature recorded in July in the UK was 98F in Surrey (2006).
The lowest ever temperature recorded in July in the UK was 27F in Highland (1977) and Powys (1986).

Hot temperatures in July usually are accompanied by high humidity, but not always.