On the interior plateau the altitude – Johannesburg lies at 1 694 m – keeps the average summer temperatures below 30°C. In winter, for the same reason, night-time temperatures can drop to freezing point or lower in some places. South Africa’s coastal regions are therefore relatively warm in winter. There is a striking contrast between temperatures on the country’s east and west coasts, owing respectively to the warm Agulhas Current and cold Benguela Current that sweep the coastlines.