O'Higgins/San Martín Lake

Lake Large glacial lake on the Argentina–Chile border

A deep transboundary lake straddling Chile and Argentina, O’Higgins/San Martín attracts boat trips, glacier views and trekking in remote Patagonian fjords within adjacent national parks.

Main image

O’Higgins / San Martín Lake is a large glacial lake in southern Patagonia that lies on the border between Chile and Argentina. It is fed by glaciers and sits in a remote mountainous region of the southern Andes.

The lake is valued for its scale and glacial scenery, with long, fjord-like arms and ice-fed waters; boat trips from the Chilean side access nearby glaciers and icefields. The shorelines are largely undeveloped, so the experience is predominantly natural rather than urban.

The basin formed and was shaped by Pleistocene glaciation and continued glacial activity, which feed the lake and surrounding rivers. Over the 20th and 21st centuries access has remained relatively limited, preserving much of the lake’s natural character.

Geographically the lake sits deep in southern Patagonia, straddling the Chile-Argentina border in the southern Andes. Nearest major centers are hundreds of kilometres away; the area is dominated by mountains, glaciers and temperate-patagonian vegetation.

  • Two-country name: Known by two names - O'Higgins on the Chilean side and San Martín on the Argentine side - reflecting its position on the international border.
O'Higgins/San Martín Lake
O'Higgins / San Martín Lake (shared Argentina/Chile, Patagonian region)
-48.8667, -72.6667

Tips for Visiting O'Higgins/San Martín Lake #

  • Remember the lake has two names-O'Higgins in Chile and San Martín in Argentina-and the most practical public access point is from Villa O'Higgins on the Chilean side via the Carretera Austral; plan logistics around that end.
  • Visit in the Southern Hemisphere summer (December-February) when boat services and weather are most reliable and the glacier-fed icebergs and shoreline viewpoints are at their most visible.
  • Book any boat excursions in advance and aim for the early departures of the day to increase chances of calmer water and clearer visibility of glacial fronts and icebergs that many day visitors miss.

Best Time to Visit O'Higgins/San Martín Lake #

Visit in the austral summer (December-February) for the best access, milder conditions and available services.

Summer (best access)
Dec-Feb · 5-15°C
Austral summer offers the most reliable access by boat/road and milder conditions for exploring the lake region; services and excursions are most available.
Shoulder seasons
Oct-Nov, Mar-Apr · 0-10°C
Cooler and more changeable weather; access can be more limited and conditions less predictable than mid-summer.
Winter
Jun-Aug · Below freezing possible
Cold, often snowy and many routes and services are closed-generally not a practical time for visits.

Weather & Climate near O'Higgins/San Martín Lake #

Climate

O'Higgins/San Martín Lake's climate is classified as Oceanic - Oceanic climate with cool summers (peaking in January) and cold winters (coldest in July). Temperatures range from 0°C to 18°C. Moderate rainfall (686 mm/year).

Temperature & Rainfall
Temperature Range
18°
Warmest Month
Coldest Month
Monthly Conditions

January

January is cool with highs of 18°C and lows of 8°C. Moderate rainfall (54 mm) and breezy conditions.

Comfort

13°
Feels Like Cool
13°C
Temperature
18°

Weather

54 mm
Rainfall
7.4 m/s
Wind
Breezy

February

February is cool with highs of 17°C and lows of 8°C. Moderate rainfall (54 mm) and breezy conditions.

Comfort

13°
Feels Like Cool
13°C
Temperature
17°

Weather

54 mm
Rainfall
6.4 m/s
Wind
Breezy

March

March is cool with highs of 16°C and lows of 6°C. Moderate rainfall (64 mm).

Comfort

11°
Feels Like Cool
11°C
Temperature
16°

Weather

64 mm
Rainfall
5.4 m/s
Wind
Light Breeze

April

April is cold with highs of 13°C and lows of 4°C. The wettest month with 81 mm of rain.

Comfort

Feels Like Cold
C
Temperature
13°

Weather

81 mm
Rainfall
5.0 m/s
Wind
Light Breeze

May

May is cold with highs of 9°C and lows of 2°C. Moderate rainfall (77 mm).

Comfort

Feels Like Cold
C
Temperature

Weather

77 mm
Rainfall
3.8 m/s
Wind
Light Breeze

June

June is cold with highs of 7°C and lows of 1°C. Moderate rainfall (62 mm).

Comfort

Feels Like Cold
C
Temperature

Weather

62 mm
Rainfall
3.6 m/s
Wind
Light Breeze

July

July is the coolest month with highs of 7°C and lows of 0°C. Moderate rainfall (47 mm).

Comfort

Feels Like Cold
C
Temperature

Weather

47 mm
Rainfall
3.5 m/s
Wind
Light Breeze

August

August is cold with highs of 8°C and lows of 0°C. Moderate rainfall (56 mm).

Comfort

Feels Like Cold
C
Temperature

Weather

56 mm
Rainfall
4.4 m/s
Wind
Light Breeze

September

September is cold with highs of 10°C and lows of 2°C. Moderate rainfall (48 mm).

Comfort

Feels Like Cold
C
Temperature
10°

Weather

48 mm
Rainfall
5.3 m/s
Wind
Light Breeze

October

October is cold with highs of 13°C and lows of 5°C. Moderate rainfall (54 mm) and breezy conditions.

Comfort

Feels Like Cold
C
Temperature
13°

Weather

54 mm
Rainfall
6.4 m/s
Wind
Breezy

November

November is cool with highs of 14°C and lows of 6°C. Moderate rainfall (43 mm) and breezy conditions.

Comfort

10°
Feels Like Cool
10°C
Temperature
15°

Weather

43 mm
Rainfall
7.1 m/s
Wind
Breezy

December

December is cool with highs of 16°C and lows of 8°C. Moderate rainfall (46 mm) and breezy conditions.

Comfort

12°
Feels Like Cool
12°C
Temperature
16°

Weather

46 mm
Rainfall
7.4 m/s
Wind
Breezy

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