The effect of the Gulf Stream on Britain and Ireland means that they both have milder winters than their northerly position would otherwise suggest.
This means that the hardiness zones relevant to Britain and Ireland are quite high (7 to 10).
- In Scotland – the Grampians, Highlands and locally in the Southern Uplands.
- In England – the Pennines
- In Wales the highest part of Snowdonia.
- Most of England, Wales and Scotland, and parts of central Ireland.
- Most of western and southern England and Wales, western Scotland, also a very narrow coastal fringe on the east coast of Scotland and northeast England (within 5 km of the North Sea), London, and most of Ireland.
- Very low lying coastal areas of the southwest of Ireland and the Isles of Scilly.