Quick reads. Lasting takeaways.
High pressure settles over the Western Alps for the next three days. Chamonix and Zermatt both stay dry, with valley highs near 26 degrees and barely any cloud. That is a rare rain-free window for a longer traverse. Start early. By midday the exposed sections bake, and under a clear sky the UV at 2,000 metres bites harder than the thermometer suggests. Carry more water than a cooler day would ask for.
Hydration packs ↗Valley temperatures around Chamonix reach 26°C this week, and even at Zermatt's 1,600 metres the nights barely drop below 14°C. That is warm for altitude. On south-facing trails the sun does the work long before noon, so start early and carry more water than a spring hike would need. A litre every two hours is a sensible floor in this heat. Save the exposed ridgelines for the cooler morning air.
Hydration packs ↗The Chamonix valley takes around 26 millimetres of rain today before the sky clears. Wednesday and Thursday then stay dry, with highs near 24 degrees. The window is the afternoon. Sit out the wet morning, head up once it breaks, and pack a proper waterproof shell over a packable emergency layer. One valley east, Zermatt stays dry throughout at a calm 24 degrees.
Waterproof jackets ↗Chamonix sits under a clear sky this morning, yet the valley is climbing towards 30 degrees. That heat has a cost. By early afternoon the moisture lifts and thunderstorms build over the ridges; today's forecast already shows rain stacking up, with more of it tomorrow. Summit early, be off the exposed sections by one o'clock, and carry a shell even when the morning looks flawless.
Waterproof shell jackets ↗August in the high Pyrenees is not the Mediterranean people pack for. At 2,000 metres the highs barely reach 12 degrees, mornings drop to 4, and mid-week brings around 8 millimetres of rain on gusty showers. Bring a proper shell and a warm layer. A sun hat alone won't cut it up here. The wind is the real tell, not the number on the thermometer.
Waterproof shell jackets ↗Valleys around Chamonix and Zermatt push past 26 degrees this weekend, and the first afternoon showers return on Sunday. Classic August pattern. Warm, still mornings give way to building cloud by early afternoon, so start at dawn and aim to be off exposed ridges by two. At 1,600 metres it is still only 13 degrees at first light, which makes a light shell worth carrying even when breakfast looks settled.
Lightweight shell jackets ↗In the Alps this week the pattern is fixed: bright mornings, wet afternoons. Zermatt sat under an open sky at 15°C at 1,600 metres this morning, yet its daily rain total climbs from under 2mm today to over 3mm tomorrow, almost all of it after midday. Chamonix reads the same, clear until noon and clouding over by three. Start at dawn. A summit reached by eleven beats a thunderstorm at three, and the walk down stays drier for it.
Waterproof jackets ↗Chamonix reaches 31°C in the valley today under clear skies. Make the most of it. A front pushes through tomorrow: highs drop to around 26°C with 4 to 5mm of rain across the western Alps, and Zermatt cools to roughly 21°C by Saturday. If you are heading up, take the dry morning and pack a shell for the turn. The heat won't last.
Waterproof shell jackets ↗The Tour du Mont Blanc is essentially clear now. As of early July only isolated snow lingers: the gullies between Champex and Trient, a short crossing near Le Brévent, the approach to the Col du Bonhomme. Valleys sit at 15 to 25 degrees, the high passes near five. That is a twenty-degree swing in one ascent. Carry a windproof softshell you can pull on without dropping the pack, and leave the microspikes at home unless old snow makes you uneasy.
Softshell jackets ↗Alpine thunderstorms are back on their summer schedule. On hot days they build through the afternoon and often fire between 14:00 and 16:00. Lightning on an exposed ridge is no joke. Start by seven, aim to be off the high ground by midday. If the sky stacks up while you are still on a pass, descend straight away rather than waiting it out. The reward comes at dusk, when the storms clear and the peaks glow.
Hardshell jackets ↗High pressure has settled over the Western Alps. Chamonix and Zermatt both show three dry days ahead, with valley highs climbing from 22 to 28°C by Wednesday. That warmth is the catch. Afternoon heat softens the snow on the high routes and saps your legs on the way out. Start before dawn, top out by midday, and you keep firm ground under your boots and cool air in your lungs. A head torch earns its place in the pack.
Head torches ↗Chamonix takes more than 20mm of rain today at 14 degrees, then dries out completely. By Tuesday the valley climbs past 28 degrees. That is a swing of over ten degrees in two days. Zermatt follows the same pattern, a touch cooler up high. The trails stay greasy. Pack a light waterproof shell for the wet morning and grippy soles for the mud that lingers once the sun returns.
Waterproof jackets ↗High summer settles the Alps for days, then breaks the pattern in two hours. The rule on Swiss and French routes: cross any pass above 2,000 metres before noon, and be back at hut level by early afternoon. Thunderstorms build fast up there. The standard Tour du Mont Blanc is snow-free now, but higher variants still hold patches near the Col du Bonhomme. Start early. Check the sky, and turn back if it darkens.
Hardshell jackets ↗The freezing level across the Alps is sitting above 4,000 metres. On glacier routes that means no overnight refreeze, and snow bridges that soften by mid-morning. Start before dawn. Zermatt still holds the most open terrain, but the high ground is shrinking week on week. Lower down, the Tour du Mont Blanc is largely snow-free, with only patchy gullies lingering near the Col du Bonhomme. Carry more water than the map suggests.
Hydration packs ↗Across the western Alps the pattern is set. Mornings sit near 14°C, afternoons climb past 20°C, and storms build between two and five. Snow has mostly gone above 2,500 metres, so the trails run dry. The catch is the clock. Start at six, be off the exposed ridges by early afternoon, and a packable hardshell settles the question when the sky turns.
Hardshell jackets ↗High pressure has settled over the western Alps: three dry days from Chamonix to Zermatt, clear skies, valley highs near 25 degrees. But clear nights bleed the heat straight back out. Zermatt drops to 10 degrees in the valley, and above 2,500 metres you will set off below freezing. That is the catch of a settled spell. Warm afternoon, brutal alpine start. A wind shell over a merino base covers both ends without the midlayer you carry unused by noon.
Merino base layers ↗
