At Fitz Roy’s height the wind comes from the western sector 70 % of the hours with wind (between south-west and north-west). The three most frequent directions: NW 41 %, NNW 25 %, WNW 24 %. It is the Pacific wind, straight, with nothing to bend it.
In town the story changes: the Río de las Vueltas valley runs north to south, with high walls on both sides, and the west wind that crosses the range comes down into the valley and follows it. That is why in El Chaltén the reanalysis sees the wind coming in from the north and north-west: N 41 %, NNO 25 %, NNE 13 %. Anyone who has walked down Avenida San Martín with the wind at their back knows it.
What each direction says
- West and north-west
- The normal wind. Dry and relatively mild on the Argentine side. The stronger it is, the more cloud over the massif.
- North
- Usually ahead of a front: warmer, wetter air, high cloud, the hat on Fitz Roy. A warning.
- South and south-west
- After the front: cold, clean air, the sky opens, it may snow up high. The next day is usually clear.
- East
- Rare, and almost always with little wind. An east day is a still day, sometimes with low cloud off the steppe.
The two roses, by season
| Place | Trekking season (Oct–Mar) | Rest of the year (Apr–Sep) | Calm hours |
|---|---|---|---|
| Fitz Roy’s height, 3,405 m | NW 44 % | NW 36 % | 17 % |
| El Chaltén, 400 m | N 35 % | N 48 % | 21 % |
The most frequent direction in each season and its share of hours; “calm” = under 5 km/h. Hourly ERA5 reanalysis, 2016 to 2025, via Open-Meteo. The reanalysis sees the relief in large cells: it is the tendency, not a vane in the square.
The full roses, with all 16 sectors, are drawn in the wind guide: Read more →
Questions
Which direction does the wind blow from in El Chaltén?
From the west and north-west up high (70 % of hours with wind come from the western sector). In town, the Río de las Vueltas valley channels it and it comes in from the north and north-west.
What happens when the wind comes from the south?
Cold air arrives behind a front. It usually clears, the temperature drops and it snows on the summits, sometimes in town too outside summer.
Is there ever an east wind?
Very little. When there is, it is a still day. Sometimes it brings low cloud off the steppe that covers town while it is clear up high.