Hiking in rain, heat and cold

The short answer

Dress in layers you can add and shed, never rely on cotton, and always carry rain protection and one warm layer even on a nice day. In heat, start early, cover up, and drink steadily; in cold and wet, keep your core and a spare layer dry and keep moving. Above all, check the forecast before you go and be willing to turn back.

Read the forecast like a hiker

A valley-town forecast tells you little about a ridge 3,000 feet higher. Look for a mountain- or point-specific forecast, and read it for the things that actually hurt hikers, not just the sunshine icon.

• Wind is the hidden danger — it drives the wind-chill that causes cold injuries and makes exposed ridges dangerous.
• Timing of storms: in many mountains, thunderstorms build in the afternoon, so summit early and be heading down by midday.
• Temperature swings: expect it to be far colder up high, at night, and in wind — plan for the coldest number you might see, not the warmest.

The layering system

Layering lets one kit handle a huge range of conditions. Think in three roles, and add or drop layers before you're soaked in sweat or shivering — not after.

1. Base layer (against the skin): synthetic or merino wool that moves sweat away and stays warm damp. Never cotton.
2. Insulating layer (traps warmth): a fleece or a light puffy for breaks, higher elevations and cold mornings.
3. Shell layer (blocks wind and rain): a waterproof-breathable jacket, and often rain pants, that goes on before you're cold and wet.

The trick is to hike slightly cool. You warm up fast once moving, so start a little chilly and vent or shed layers as you climb.

Hiking in the rain

Rain is manageable and even beautiful — as long as your core and your spare layers stay dry and you don't get chilled by wind on top of the wet.

1. Keep the important things dry: line your pack, and seal your insulating layer, sleep gear and electronics in dry bags — see our waterproofing guide.
2. Manage sweat: a rain shell traps moisture, so open the pit zips and slow your pace to avoid soaking from the inside.
3. Protect your feet and warmth: gaiters and a hat help; if you get cold, add a layer, eat, and keep moving to generate heat.

Hiking in the heat

Heat is deceptively dangerous, especially on exposed desert and canyon trails. The goal is to move heat away from your body and keep hydration and electrolytes topped up.

1. Beat the clock: start at dawn, do the climbing early, and rest in shade during the hottest hours.
2. Cover, don't strip: a light long-sleeve shirt, sun hat and sunglasses shade you better than bare skin; a wet bandana on the neck cools you.
3. Drink and salt steadily: sip water before you're thirsty, plan around reliable water sources, and replace salt with food or electrolytes — plain water alone isn't enough on a big hot day.

Hiking in the cold

Cold is mostly about staying dry and out of the wind, and eating enough to keep your internal furnace running.

1. Stay dry: wet — from sweat or weather — is what turns cold into danger, so vent while climbing and layer up the moment you stop.
2. Cover the extremities: a warm hat, gloves and buff hold in a surprising amount of heat; keep circulation going with movement.
3. Fuel the fire: eat and drink regularly (warm drinks help morale), because a well-fed body makes heat and a hungry one gets cold fast.

Spotting trouble early

The two conditions to know are hypothermia (getting dangerously cold) and heat exhaustion / heat stroke (overheating). Both are far easier to head off than to fix, and both cloud judgment — so watch your companions, not just yourself.

• Cold trouble: hard shivering, clumsiness, slurred speech and confusion. Get out of wind and wet, add dry layers, give warm food and drink, and keep moving or seek help.
• Heat trouble: heavy sweating, headache, nausea, dizziness and cramps. Stop, get into shade, cool down, sip water with electrolytes, and rest before continuing.
• Escalation: if someone stops shivering but stays cold and confused, or stops sweating and becomes hot, disoriented or unconscious, treat it as a medical emergency and get help immediately.