The vegetation is dominated by the woody shrub Leptospermum scoparium, or tea tree, which covers most parts of the island, reaching a canopy height of 6 m in sheltered places.

[5] Because the island is so far south and is entirely dominated by circumpolar weather systems, mean temperatures are significantly colder than most of Australia.

Maatsuyker Island has an annual mean temperature of around 11 °C (52 °F) with strikingly cool summers that are reminiscent of those in northern Scotland, despite sharing a latitude with Nice in southern France.

Weather conditions in the area can be extreme, with the Roaring Forties wind being a particular problem.

Due to the high vegetation in patches on the top of the island, it is possible to shelter on the "jeep trail" that runs from the lighthouse to the landing.