Map from Google - Falkland_Islands

The climate of the Falkland Islands (or Malvinas), is maritime cold: winter is cold, windy and snowy, while summer is very cool, if not cold, and it's rainy and windy as well. Relative humidity is high, and the sky often cloudy throughout the year. In autumn and winter, winds can be stormy. The islands are located in the South Atlantic Ocean, therefore they have reversed seasons compared with the Northern Hemisphere.
The average daily temperature of the warmest months, January and February, is about 10 °C, with highs around 14 °C, while that of the coldest months, namely June, July and August, is about 2 °C, with highs around 3/4 °C. This means that the climate of these islands is almost subpolar, and it's similar to that of Iceland, even though it's slightly milder.
The influence of the sea and the constant winds reduce the temperature range, so the islands rarely experience a warm weather, as well intense frosts: the highest recorded temperature is 26 °C, while the coldest is -11 °C. However, in the colder period, from April to October, snowfalls are frequent, in addition, the wind and the humidity exacerbate the feeling of cold. Some cold nights, with minimum around freezing, are possible even in summer, and in inland hills, snowfalls can occur even in this season.
Here are the average temperatures of Port Stanley.
Average temperatures - Port Stanley
Port StanleyJanFebMarAprMayJunJulAugSepOctNovDec
Port StanleyJFMAMJJASOND
Min (°C)776320111246
Max (°C)14141286345691113

Precipitation is not abundant, since it does not reach 550 millimetres per year, because a part of it is discharged over Chile, on the western Andean slopes, which are not far; however, the rains are frequent and well distributed throughout the year. In fact, the westerlies blow all the year round, so that weather fronts pass over the islands one after the other, bringing clouds and rain (or snow), interspersed with sunny intervals, usually not lasting, or a variable or unstable weather.
Here is the average precipitation in Port Stanley.
Average precipitation - Port Stanley
Port StanleyJanFebMarAprMayJunJulAugSepOctNovDecYear
Port StanleyJFMAMJJASONDY
Prec. (mm)654550505045404035354050545
Days1311101111101098101112125

Stanley

In the Falkland Islands the sea is cold all year round, as can be seen in the following table.
Sea temperature - Port Stanley
Port StanleyJanFebMarAprMayJunJulAugSepOctNovDec
Port StanleyJFMAMJJASOND
Sea (°C)999876555678

When to go

The best time to visit the Falklands is the austral summer, from December to February, being the mildest. Even in this period there are winds and rains, and sometimes it can be a bit cold. It will, therefore, be useful to bring warm clothes.

What to pack

In winter (June to August): warm clothes, down jacket, hat, gloves, wind jacket, raincoat or umbrella.
In summer (December to February): sweater, shirt, jacket, raincoat or umbrella.