What to Wear Trail Running in Summer Heat (Without Overheating)
Slowing down helps on a hot run, but what you're wearing does more of the work than most people give it credit for. Cotton in particular is worth avoiding entirely on trail: it holds onto sweat instead of moving it, which keeps moisture against your skin and increases chafing right when you least want it.
Fabric matters more than the cut
Synthetic blends and merino wool both pull moisture away from your skin so it can evaporate, which is the actual mechanism behind feeling cooler, not just a marketing claim. Look for this over anything that soaks up sweat and holds it.
Colour and construction
Light colours reflect heat instead of absorbing it, which makes a real difference on exposed, sun-heavy sections of trail. Mesh panels and seamless construction help too, since ventilation and fewer seams both reduce the chafing that shows up on long, sweaty efforts.
Timing beats gear on the hottest days
Running early morning or later in the evening avoids peak heat entirely, which does more for comfort than any single piece of clothing. On unavoidable midday runs, a neck gaiter soaked in cold water and worn loosely is a genuinely effective way to bring your core temperature down without adding weight.
Know the signs of heat illness
On hot runs, clothing helps, but knowing when to stop matters more. The U.S. National Weather Service lists these signs:
- Heat exhaustion: heavy sweating, weakness or tiredness, cool, pale, clammy skin, a fast, weak pulse, muscle cramps, dizziness, nausea or vomiting, headache, fainting. Move to a cooler place, loosen clothing, use cool, wet cloths and sip water. Get emergency care if the person vomits, symptoms get worse or last longer than one hour.
- Heat stroke: throbbing headache, confusion, slurred speech, nausea, dizziness, body temperature above 103°F, hot, red, dry or damp skin, a rapid and strong pulse, fainting or loss of consciousness. Call 911 or get to a hospital immediately; the National Weather Service calls heat stroke a severe medical emergency. Cool the person down, and do not give fluids.
Run smarter in the heat
- Run early or late, and slow down when it is hot.
- Build up gradually: start with shorter, easier runs in the heat before long ones.
- Carry more water than you would on a cool day, and plan refills; see how much water to carry.
- Protect your skin and eyes; see sun protection for trail runners.
Source: National Weather Service, heat illness. General information, not medical advice.
What's coming from LECAMO
LECAMO's Apparel line is built around exactly this: quick-dry fabric designed for hot, changing trail conditions, made to work with the ROOT pack range rather than against it. It's not live yet, but if summer heat is the thing slowing you down, join the list below and you'll hear the moment it launches.