London has one of the strongest weather stereotypes in the world.

Mention the British capital and many people imagine umbrellas, grey skies, wet pavements and seemingly endless drizzle.

So it may come as a surprise that London is not particularly wet by European standards.

According to the Met Office’s 1991–2020 climate normals, Heathrow receives about:

615 mm of precipitation per year.

That is enough rain to keep the city green, but it is far below the totals found across some of Europe’s Atlantic coasts and mountainous regions. (Met Office)

As the map shows, vast areas of:

western Norway,

Scotland,

Ireland,

western France,

northern Spain,

the Alps,

the western Balkans

and other mountainous regions

are wetter than London.

Meanwhile, large parts of continental Europe—including portions of Germany, Poland, Spain, Scandinavia and eastern Europe—receive less annual precipitation than Heathrow.

The result is a fascinating divide:

London is neither one of Europe’s wettest places nor one of its driest.

It sits somewhere in the middle.

First, What Does 615 mm of Rain Actually Mean?

Rainfall is usually measured in millimeters.

If 615 mm of precipitation fell evenly onto a perfectly flat surface without draining or evaporating, it would form a layer of water:

61.5 centimeters deep.

That sounds like a lot.

But climate statistics become meaningful only through comparison.

The Met Office’s Heathrow climate normal shows relatively modest monthly rainfall throughout the year.

For example:

January — 58.83 mm

March — 38.78 mm

July — 45.80 mm

October — 65.07 mm

November — 66.63 mm

December — 57.05 mm

Together, the 12 monthly averages total 614.98 mm annually. (Met Office)

Notice something interesting:

London does not have one dramatic wet season.

Rain is spread fairly evenly throughout the year.

That helps explain the city’s reputation.

London Can Feel Rainier Than It Actually Is

This is the key distinction.

There are at least two ways a place can seem rainy:

It can receive a huge volume of rain.

Or:

It can experience frequent periods of lighter rain and cloudy weather.

London is much closer to the second category.

You may encounter drizzle, short showers and damp grey days without accumulating enormous annual rainfall totals.

By contrast, another European city might experience fewer rainy days but receive intense downpours that contribute much more water to the annual total.

So:

“How often does it rain?”

and

“How much rain falls?”

are not the same question.

This infographic measures the second.

Why Western Britain Is Much Wetter Than London

The map reveals another important point:

London is not representative of the whole United Kingdom.

The Met Office’s 1991–2020 average for the entire UK is about 1,163 mm annually—almost twice the Heathrow figure. (Met Office)

Why such a huge difference?

Geography.

Much of Britain’s moisture arrives from the Atlantic.

Prevailing weather systems frequently travel from west to east.

The first high ground they encounter includes mountainous parts of:

Wales,

northwestern England

and especially Scotland.

Moist air is forced upward over the terrain.

As it rises, it cools.

Water vapor condenses.

Rain falls.

This process is known as orographic precipitation.

By the time air reaches southeastern England, including London, some of its moisture has already been lost.

That helps make the southeast considerably drier than western Britain.

So the classic British rain stereotype makes much more sense in places such as western Scotland than in London itself.

Norway Makes London Look Dry

Perhaps the most dramatic blue area on the map is western Norway.

The Norwegian coastline faces moisture-bearing North Atlantic weather systems, while mountains rise steeply just inland.

That is an ideal setup for heavy orographic rainfall.

Meteorological research describes western Norway as having very strong rainfall gradients because mountain ranges enhance precipitation on their windward sides while producing rain shadows on the other side. (Met Office)

That explains the striking pattern visible on the infographic.

Western slopes appear deep blue.

Move inland or across the mountains and precipitation can decrease rapidly.

In other words:

A mountain range can transform the climate within a surprisingly short distance.

The Alps Create Another Wet European Belt

The same principle appears across the Alps.

Look at:

Switzerland,

northern Italy,

Austria,

Slovenia

and surrounding Alpine regions.

Blue follows much of the mountain chain.

Air moving toward the Alps is forced upward.

That enhances precipitation on exposed slopes.

But areas behind the mountains can be substantially drier because they lie in a rain shadow.

This is why precipitation maps often resemble topographic maps.

Mountains are among Europe’s strongest controls on rainfall.

The Balkans Have Extremely Wet Mountain Areas Too

The deep blue band along portions of the Adriatic side of the Balkans is another striking feature.

Moist air from the Adriatic Sea encounters steep terrain relatively quickly.

Parts of:

Slovenia,

Croatia,

Bosnia and Herzegovina,

Montenegro

and Albania

therefore receive much more precipitation than many people might expect from southeastern Europe.

The Mediterranean is often associated with sunshine and dry summers.

But mountains close to warm seas can create enormous rainfall totals, particularly during wetter seasons.

That is why some of Europe’s rainiest locations are not in Britain at all.

Northwestern Spain Is Much Wetter Than Central Spain

Spain demonstrates another excellent rainfall contrast.

Much of the interior is shown as drier than London.

But the northwestern and northern edges become blue.

Why?

Atlantic weather systems.

Northern and northwestern Spain are directly exposed to moist Atlantic air.

Mountain barriers then enhance rainfall.

Move farther inland and precipitation falls considerably.

So “Spain is dry” is no more accurate than saying “Britain is wet.”

Both countries contain major regional differences.

France Is Split Too

The map shows large portions of France near or above London’s benchmark, particularly toward Atlantic-facing and mountainous regions.

But other parts are relatively dry.

Again, several influences overlap:

Atlantic moisture in the west,

mountains in the southeast,

Mediterranean climate in the south,

and more continental conditions toward the interior.

France’s size means it spans several European climate regimes.

London’s 615 mm benchmark cuts right through this complicated pattern.

Central Europe Is Surprisingly Dry in Places

One of the more interesting yellow zones extends across parts of:

Germany,

Poland,

Czechia,

Hungary

and eastern Europe.

These areas are farther from the Atlantic Ocean and often less directly exposed to moisture-bearing maritime weather systems.

The Met Office describes much of Europe’s interior as having a more continental climate, farther removed from Atlantic influence. (Met Office)

Continentality is particularly noticeable in temperature:

hotter summers,

colder winters,

larger seasonal temperature ranges.

But it can also influence precipitation.

Some inland lowlands receive surprisingly modest annual rainfall compared with London’s 615 mm.

Scandinavia Is Not Uniformly Wet Either

The map of Scandinavia is especially revealing.

Western Norway is extremely wet.

Yet move east across the Scandinavian Mountains and large areas of Sweden and Finland become much drier.

The mountains intercept Atlantic moisture before it travels eastward.

The Met Office notes that parts of northern Sweden and Finland have drier climates partly because the Scandinavian mountains weaken incoming weather systems. (Met Office)

So Sweden can sit only a few hundred kilometers from extremely wet western Norway while receiving dramatically less precipitation.

Again:

topography matters as much as latitude.

Mediterranean Does Not Simply Mean Dry

The Mediterranean region is complicated too.

Large inland and lowland areas can receive less annual rain than London.

But mountainous coastal areas can receive far more.

Another important difference is seasonality.

Mediterranean climates typically have:

dry summers

and

much wetter winters.

The Met Office notes that southern Europe and northern Africa receive much of their rainfall between roughly October and March. (Met Office)

London’s rainfall is more evenly distributed.

So two locations could receive similar annual totals while experiencing completely different weather.

London:

moderate precipitation scattered across the year.

Mediterranean location:

long summer drought followed by intense autumn or winter rainfall.

A single annual number cannot show that difference.

Why Does London Have Such a Rainy Reputation?

If London is not especially wet, where did the stereotype come from?

Several factors probably reinforce it.

Rain occurs throughout the year

There is no dependable dry season.

A visitor can encounter showers in almost any month.

British weather is highly changeable

Atlantic weather systems frequently alter conditions.

A sunny morning can turn grey and wet surprisingly quickly.

Rain is often light rather than spectacular

Drizzle may not add much to the rain gauge, but it can make an entire day feel damp.

Cloudiness matters psychologically

A grey day without heavy rain can still feel like “bad weather.”

British culture constantly talks about weather

Rain has become embedded in Britain’s cultural image through books, film, television and everyday conversation.

London therefore has a weather reputation that is stronger than its annual rainfall total.

London Versus the Rest of Britain

This may be the most important misconception the map corrects.

People often use “London weather” and “British weather” almost interchangeably.

They shouldn’t.

Heathrow:

about 615 mm/year.

UK overall:

about 1,163 mm/year. (Met Office)

That is a huge difference.

London sits in one of Britain’s relatively dry regions.

If the benchmark were instead based on western Scotland, Wales or another wet upland location, the map of Europe would look completely different.

Much more of the continent would appear dry by comparison.

Why Use the 1991–2020 Climate Normal?

The map uses a 30-year period for a reason.

Weather changes enormously from one year to another.

One year can be exceptionally wet.

Another can experience drought.

Climate normals smooth out those short-term fluctuations.

The period 1991–2020 is a standard modern climate-normal period used by meteorological agencies.

For the European comparison, E-OBS provides gridded daily observational precipitation and other weather variables derived from national meteorological station networks across Europe. (Climate Data Store)

That makes it useful for producing consistent continental maps.

One Important Limitation of the Map

The blue-versus-yellow design is intentionally simple.

But 616 mm and 1,600 mm are both colored “wetter than London.”

Likewise:

600 mm

and

250 mm

are both simply “drier.”

Those are very different climates.

So the map answers one narrow question extremely well:

Does this place receive more or less annual precipitation than London Heathrow?

It does not tell us how much wetter or drier every location is.

For that, a continuous precipitation scale would be more informative.

Accuracy Note for the Infographic

The London ≈615 mm/year benchmark is accurate. The Met Office gives Heathrow’s 1991–2020 annual average rainfall as 614.98 mm, so rounding to 615 mm is entirely reasonable. (Met Office)

The source combination is also appropriate. The Met Office provides the station benchmark, while E-OBS is a gridded European observational climate dataset derived from ECA&D station data supplied by national meteorological services. (Climate Data Store)

I would only add this note to the finished graphic:

“London benchmark refers to Heathrow station. Blue/yellow indicates annual precipitation above or below 614.98 mm; it does not show rainfall frequency or intensity.”

That makes the visualization much harder to misinterpret.