Two Bays a Few Miles Apart Get Different Weather

Driving along a coast on a mixed day, one bay is bright and still while the next is grey and blowing. These are real differences, produced by geography rather than chance.

Aspect decides how much sun the bay receives

A bay facing towards the sun's track receives direct light for most of the day, while one facing away is shaded by its own headland for part of it.

The difference is largest in the shoulder seasons, when the sun is low and a modest cliff can put half a beach into shadow by mid-afternoon.

Sand temperature, water temperature in the shallows and how long the beach stays comfortable all follow from this, and none of it appears in a forecast.

Shelter depends on the wind of the day

A bay is sheltered from some directions and exposed to others, so its reputation for calm holds only while the wind stays in its usual quarter.

Because the wind direction changes far more often than the geography does, the sheltered option on a coast moves from one bay to another through the week.

Local knowledge of which beach works in which wind is the single most useful piece of information on any coast, and it is freely given if asked.

Rising ground makes and unmakes cloud

Air forced upward over hills behind a coast cools and forms cloud, so a bay with high ground immediately inland is often overcast while a low-lying one nearby stays clear.

Descending on the far side of the same hills, the air warms and the cloud evaporates, which produces a persistently brighter strip in the lee.

These patterns repeat reliably enough that they become part of local reputation, and places described as having their own weather generally do.

Fog picks its landfall

Sea fog drifts in on the wind and follows the water, so it can fill one inlet completely while the headland beside it stands in sunshine above the layer.

It is also thin, often only tens of metres deep, which is why climbing a short distance up the hill behind can put you above it entirely.

Moving a few miles along the coast, or a short way inland, is frequently a more effective response to fog than waiting for it to clear.

Using this rather than being caught by it

A coastal day works better with two or three options in different aspects than with a single plan, because switching costs a short drive and solves most conditions.

Webcams and recent photographs are more useful than forecasts at this scale, since the variation is finer than the grid any model works on.

The general forecast still tells you the wind direction, and with a map that is usually enough to work out which side of the coast will be worth visiting.