The lack of reliable weather forecasts makes mountaineering in the Andes harder to plan. By exploring the different forecasts listed below, you can better assess the likelihood of getting a good-enough weather window for your summit bid.

Interpreted forecasts

The following forecasts are interpreted and are more user-friendly:

• Meteo Exploration: Offers forecasts for specific summits all along the cordillera, from Ojos al Salado in the North (Puna de Atacama) to the Monte Sarmiento in Tierra del Fuego. It also offers maps of precipitation that require interpretation.
• Snow forecast for Portillo, Aconcagua, Penitentes, Vallecitos, Las Leñas, Farrellones, Valle Nevado and Chillán. The main advantage of this service is that in some ski resorts, it also gives past snowfall and weather which helps in assessing avalanche risk. Beware that some resorts seem to be miss-placed.
• Chicureo (in Spanish) for Portillo (Chile) and Punta de Vacas (Argentina) based on Accuweather and the official chilean forecast for the city of Los Andes (when it is raining there, it is most likely snowing on the border).
• Mountain forecasts for Chile by the Servicio meteorológico nacional de Chile (in Spanish).
• Servicio meteorológico nacional argentino for Punta de Vacas (in Spanish).

Forecasts with no interpretation (raw data)

The following forecasts are more detailed by require some basic knowledge in meteorology to be interpreted. They are not so user-friendly.

• The US government NOAA website
  Often provides the most accurate forecasts but can be difficult to interpret. You must first enter the coordinates of the location you are interested in, select the length of the forecast (90 hours, 180 hours...) and click on "meteogram". You can then choose to include or remove variables from the forecast. Coordinates for summits, access-points, huts and climbing sites are available in the camptocamp.org guidebook.

Useful coordinates include:
Puente del Inca: -32.825206 y -69.909692
Salto del Agua (Cordón del Plata): -69.41338 y -32.97987
Arenales (Cordón Portillo): -69.516226 y -33.623181