With temperatures across the UK forecast to climb to 34°C this week, the warmest weather of the year so far, thousands of runners will be heading out into conditions they simply haven’t trained for. This kind of weather catches even experienced marathoners off guard, and the difference between a comfortable run and a ruined session very often comes down to the preparation steps you’ve taken.
Guidance from both the NHS and Met Office recommends avoiding 11 am to 3 pm, when UV levels and temperatures peak. Hydrating regularly and applying SPF are also two other essential requirements when trying to keep up your training in this warmer weather. But often overlooked is what you should wear when heading out into the heat.
Matt Bond, former GB distance runner and representative for heritage British running brand Ronhill, founded by 1970 Boston Marathon winner Dr. Ron Hill MBE, has put together a quick decision guide for every layer of summer running kit, from cap to socks, to help those dedicated athletes who will keep up their training whatever the weather:
HEAD
Cap or visor (always)
“Above 22°C, a peaked cap or visor isn’t optional, it’s the single biggest perceived-effort win you can make. Shading your face keeps your core temperature lower and stops you squinting, which prevents the facial and neck tension that quietly burns energy over a long run. Light colours only; black caps absorb heat and defeat the purpose.”
Sunglasses (UV400)
“UK runners under-rate sunglasses. UV exposure on a clear 30°C day is significant, and squinting against bright light tenses the shoulders within minutes. Look for UV400 protection and a wrap-around shape that won’t bounce off mid-stride.”
UPPER BODY
A lightweight, technical vest – not a t-shirt
“In anything above 22°C, a moisture-wicking running vest will outperform a t-shirt every single time. More airflow, less fabric to absorb sweat and weight, and significantly faster cooling. If you must wear a t-shirt, choose a lightweight technical fabric with mesh panels, never cotton, which absorbs 27 times its weight in water and turns into a wet blanket by mile four.”
Light colours, always
“Black and navy kit feels great in the shop and disastrous in the sun. Dark colours absorb radiant heat and trap it against the skin. Whites, pale greys and pastel technical kits reflect heat instead. On a 30°C run, the colour of your top makes a measurable difference to perceived effort.”
LOWER BODY
Short, fitted shorts with built-in liner
“Heat changes the chafing equation: sweat saturates fabric and turns every seam into sandpaper. Look for short, fitted technical shorts with a built-in inner liner and flat-locked seams designed for endurance running. Length is personal preference; the more important question is fit. Loose, baggy fabric flaps in the breeze and adds friction.”
Distributed pockets, not one bouncy waistband
“In summer, you’ll likely carry more than you think: keys, phone, water, and a small SPF tube. Shorts with two or three small zip pockets distribute the weight evenly. A single bouncy waistband pocket throws off your gait and slaps your thigh, which over an hour becomes genuinely painful.”
FEET
Technical, double-layer or moisture-wicking socks
“Cotton socks are blister machines in hot weather. Go for technical running socks with moisture-wicking fibres, ideally double-layer socks designed to reduce friction between the sock’s inner and outer surfaces, which is where most blisters actually form. If you’re running over an hour, this single kit change can save your feet.”
Breathable shoes, not your winter pair
“Winter and trail shoes are built with reinforced, less breathable uppers to keep the weather out. In 27°C, that same upper traps heat and sweat against your foot. A summer rotation shoe with a more breathable mesh upper will feel cooler immediately and reduce blister risk.”
SKIN
SPF 30+ sweat-resistant, applied 20 minutes pre-run
“UK sunburn risk is higher than most runners realise. UV stays high under thin cloud and burns develop in under 20 minutes on a clear day. Apply SPF 30 or higher to all exposed skin at least 20 minutes before stepping out, and choose a sweat-resistant formula that won’t run into your eyes. For runs over an hour, carry a small tube to reapply.”
Anti-chafe balm in the danger zones
“Wet kit chafes far more than dry kit, so a 30°C run is a guaranteed chafing event without protection. Apply a thick anti-chafe balm to inner thighs, underarms, sports bra lines, nipples, and anywhere a heart-rate monitor or pack sits. Don’t skimp, a small amount of friction over an hour becomes raw skin.”
LEAVE AT HOME
“Heavy cotton t-shirts, the one-pocket bouncy waist belt, your winter running cap, dark technical kit, and any ‘weatherproof’ jacket that traps heat. None of them belong in a 30°C session, and most of them will quietly slow you down.”
Matt concludes:
“UK runners get caught out by sudden hot days every year because we train through eight months of cold weather. The kit choices you make on a 30°C day are the difference between a great run and one you remember for the wrong reasons.
Ronhill’s Golden Hour range is the perfect choice for a hot day like today. It is designed for optimising performance in hot weather environments by working with the body’s natural cooling process, increasing airflow and dispersing sweat.”
Photo by Mathias Reding: https://www.pexels.com/photo/runner-s-shadow-silhouette-in-black-and-white-33995259/
