The weather on Ojos del Salado decides more than whether you can go for the summit. Snow, wind and visibility change the state of the high-altitude roads, access to the camps, how the vehicles perform and how quickly an evacuation can happen. So the forecast is read for the whole expedition chain, not only for the 6893 m mark.
When the season runs
Mountain Guide group programmes are scheduled for the southern summer. That is the most sensible seasonal window, but summer in the high Atacama does not mean settled warmth. Strong wind, frost and snow are all possible at the upper camps.
Exact access dates, whether the refuges are open and any restrictions all change. Before you travel, check what the Chilean authorities say, the actual state of the roads and the forecast. It is not possible to publish a universal opening or closing date for the route in advance.
The main weather factors
Why the weather feels so sharp here
- Extremely dry air speeds up the loss of body fluid.
- Strong sun during the day gives way to rapid cooling after sunset.
- Wind makes the cold feel far more severe.
- Open terrain offers little natural shelter.
- At high altitude even simple tasks take longer.
Wind
Wind affects your balance, your warmth, your ability to manage your clothing and whether the upper section can be climbed safely. In camp it strains the tents and makes cooking harder. On summit day, strong gusts can be a reason to turn back in their own right.
Snow and the roads
Fresh snow changes a vehicle’s grip, covers the tracks, lengthens journey times and affects the decision about crampons. Even when the forecast for the summit looks acceptable, the road to Atacama or Tejos may still be impassable.
The decision about moving is taken by the team on the spot. Do not build a plan on the assumption that the vehicle will get the group up to the top camp whatever happens.
Temperature and clothing
A single average temperature tells you little about the real conditions. What matters is the overnight minimum, the wind, how damp your clothing is, how long you stand still and how sensitive you personally are to cold. Your layering system has to work both while you are moving and while you are waiting.
Boots, mitts, a face mask, a down jacket and a sleeping bag are critical equipment. There is a detailed breakdown in the equipment list for Ojos del Salado.
What the contingency days are for
The 15-day programme includes two contingency days. They let you move the attempt or adjust the plan, but they do not guarantee the weather. If the window does not come, or the roads and the team are still not in a safe state, the climb stops.
How to read a forecast
- Look at several altitudes, not just the town of Copiapó.
- Compare average wind speed against the gusts.
- Check precipitation and hour-by-hour temperature changes.
- Watch the cloud and the visibility.
- Take account of accumulated snow and of reports on the state of the roads.
- Check the online forecast against what the local team is seeing.
What cannot be promised in advance
Nobody can guarantee a particular summit day, a drive to a particular altitude, a dry final section or the use of the refuge. A properly built programme has contingency and alternatives in it, but it keeps the guide’s right to stop.
Practical preparation
Before the trip, practise changing layers quickly, putting on crampons and using a head torch while wearing gloves. In camp, store the critical items so that you can reach them at night without unpacking everything. Keep batteries out of the cold.
The full sequence is in the 15-day programme, the road conditions are covered in the article on logistics, and the reasons people turn back in our analysis of failed attempts. You can choose a format on the page listing all the programmes.
Weather on the road, in camp and on the summit
| Section | What the weather changes | Possible response |
|---|---|---|
| The road | Passability, the height of the drop-off and the timings | Stopping lower, walking a section, or calling off the drive |
| The camp | The tents, cooking and recovery | Reinforcing the camp, waiting, or going down |
| Summit day | Pace, visibility, cold and the upper section | Setting off, postponing, or turning back |
How to read the forecast before setting out
Look at the altitude the forecast is for, the time intervals, the wind speed and gusts, the temperature, the precipitation and the visibility. Compare the online model with what the driver and the guides are observing. A forecast for Copiapó does not describe Atacama or Tejos.
Your own weather margin
Check your face protection, goggles, warm gloves, spare layer, torch and a way of keeping water accessible before you go. All of it has to work in gloves and in the dark. Summit day is not the time to try the system for the first time.
The contingency days are not designated in advance as two extra attempts. They may be needed for the road, for rest, for moving camp or for a safe descent.
Three different forecasts inside one expedition
On Ojos the road, the camp and the summit all matter at once. A good window at 6893 m is no help if snow has stopped the vehicle below the planned point. A passable road does not make strong wind on the upper section safe. A secure camp says nothing about the visibility during a night start.
| Element | What data you need | Which decision it changes |
|---|---|---|
| The 4×4 road | Fresh and accumulated snow, wind, visibility and reports from drivers | The drop-off point, the number of journeys and the timings |
| The camp | Gusts, overnight cold and the state of the site | Tents, cooking, rest or descent |
| The acclimatisation walk | Hourly wind, temperature and cloud | The start, the route and the checkpoints |
| Summit day | Conditions from Tejos to the upper rock section | The attempt, the turnaround and the margin for getting back |
The online model is supplemented by what the local team observes. The driver judges the road, the guide the mountain and the state of the people. Neither role substitutes for the other.
How snow on the road changes the whole day
A lower drop-off point lengthens the walk and changes the start time, the water consumption and the team’s reserves. You cannot simply keep the old schedule and add a few kilometres: the leader recalculates the overnight stop, the decision points and the return.
| Change | What has to be recalculated | The dangerous assumption |
|---|---|---|
| The vehicle stopped lower down | Walking time and moving the loads | That people will make it up with speed |
| Tejos is not available | The overnight stop, the kit and the start | That the refuge will free up anyway |
| An extra vehicle journey is needed | Fuel, the driver and communications | That it is automatically included |
| The road closes after you have set out | The meeting point and the margin for the return | That the vehicle will wait in the same place |
This decision is not a contest of what the vehicle can do. A driver refusing to continue on an unsafe section preserves the team’s resources, and should not be argued with for the sake of a schedule.
How the forecast is used over time
A long-range forecast shows the shape of the season and helps you assemble your kit. A few days out it affects the sequence of camps and the contingency. Before a drive, the road is checked. Immediately before setting off, the actual conditions and the state of the group are assessed.
- Look at several altitudes and time intervals
- Separate average wind from gusts
- Check the state of the road, not only new precipitation
- Compare the model with what drivers and guides observe
- Do not pick the most convenient of several contradictory forecasts
- Update the decision as you go
San Francisco and the weather margin on Ojos
The ascent of San Francisco to 6018 m is an important part of the standard acclimatisation. If the weather moves it, what changes is not only an extra summit but the information about your readiness for Ojos. Missing it cannot simply be made up for by a higher drop-off.
After a hard day, recovery is assessed. Even if the weather on Ojos opens up, that is no obligation to carry on if the team has spent its reserves on San Francisco.
Wind and the upper rock section
The short rock section is at almost 6900 m. Wind affects your balance, your hands, the protection and how long the section takes. A queue, or one person moving slowly, increases how long everyone else is exposed to the cold.
The guide decides how the section is protected and may turn the group back before it. Being short technically does not make it independent of the weather, and having a rope does not guarantee safe passage in any conditions.
How to use the two contingency days
The contingency may be needed for a closed road, for moving camp, for recovery, for waiting out the wind or for a safe descent. It is not two guaranteed extra attempts. After every change, the people, the vehicles, the water, the fuel and the remaining calendar are all reassessed.
If there is no safe window, or the team’s condition has deteriorated, the right use of the contingency is to go home. Services and tickets already paid for are not weather data.
A weather briefing before each stage
| Question | What the group has to understand |
|---|---|
| What do we know? | The forecast and what has actually been observed |
| What do we not know? | The limits of accuracy and what could change |
| What is the main plan? | The place, the time, the clothing and the order of movement |
| What is the fallback? | An alternative overnight stop, a meeting point or a turnaround |
| Who decides? | The guide’s and the driver’s role, without a vote among participants |
Your personal kit as a weather system
The layers have to be adjustable on the move, and spare gloves, face protection, goggles and a torch have to come out without unpacking everything. Batteries are kept warm. Water is protected from freezing according to the team’s briefing.
After each day out, note what did not work. Goggles that fog up, food you cannot reach or gloves that do not work together get fixed before Tejos, not on the summit.
Tickets, insurance and the weather
The contingency inside the programme does not replace your own margin around the trip. Check the terms for changing your ticket in advance. Turning back for weather is not in itself necessarily an insured event: read the closed list of grounds in your policy.
An extra night or an extra vehicle journey is paid for on the terms of the programme and the supplier, unless it is explicitly included. Weather uncertainty should be visible in your budget, but no universal reserve figure can be quoted without knowing your own tickets.
How to choose dates without promising perfect weather
The southern summer remains the main working period for the programmes, but a particular date guarantees neither the wind, nor a dry road, nor the availability of Tejos. Check the official access conditions and the local logistics first, then the route and the contingency.
| Criterion | What to confirm | What not to infer automatically |
|---|---|---|
| The season | Current access and whether the services are operating | The weather from last year |
| The programme dates | The full route and the two contingency days | A summit day fixed in advance |
| Transport | That the vehicles and drivers are ready | A drive to an unchanging altitude |
| The refuge | Its actual availability and the tented alternative | A guaranteed bed inside it |
| Your ticket | The terms for changing it, and the baggage | That it will fit any use of the contingency |
If you are tied to very rigid dates, say so before you pay. Calendar pressure does not change the road and does not create a safe window.
Checks after a weather event
After strong wind or snow the team re-checks the road, the tents, the fixings, the clothing, the sleeping bags, the stoves, the fuel, the water, the batteries and the state of the people. Precipitation stopping does not mean the camp and the group are ready to carry on.
Damaged kit is repaired or replaced before the next move. If it cannot be put right, a window that opens may have to be missed. That follows from the team’s actual readiness; it is not excessive caution.
A log of decisions for the next team
The leader records the forecast, what was observed, the drop-off points, the state of the road and the camps, and the action taken. The record helps separate the properties of one particular day from the permanent characteristics of the route, and explains to the group how the contingency was used.
After the expedition, that data does not become a permanent seasonal norm. It is used as one documented case, which the next team compares against a new forecast and current reports from the local operators.
The log notes forecast and actual conditions separately. That makes it possible to see where the model was useful and where the decision rested on what a driver or a guide observed. Participants’ personal medical information is not included in the general weather report. The final entry carries a date, the section of the route and the name of the leader responsible. Changes made after the briefing are added as a separate line, with the time.
Official sources
Rules on access, permits, insurance and the operation of the services can change. Check the conditions for the date of your route before you travel.
Choosing your season and dates? Check the weather margin, the route and the length of the trip on the Ojos del Salado programmes page; the forecast for a particular departure is checked closer to the start.
Fact-checked: 17 August 2026. Roads and forecasts are checked for the particular dates.