Long-term average · Long-term average, 1981–2010, for the area around the city (CHELSA 1 km climatology)
A city's year
The chart shows a typical year around this city: the average daily high and low for each month, for the surrounding square kilometre, averaged over 1981–2010. The gap between the warmest and coldest month tells you a lot about where the city is.
Why the sea calms the seasons
Water needs four to five times more energy than dry rock or soil to warm up by the same amount, and the sea mixes heat deep down. So the sea warms slowly in summer and cools slowly in winter, and the air over coasts follows it. Inland, far from the sea, the ground heats and cools quickly, so summers are hotter and winters colder. This is called continentality.
Compare two cities
London and Moscow are at a similar latitude, but London, near the Atlantic, has a much smaller range between winter and summer than Moscow, deep inside a continent. Yakutsk in Siberia, far from any open sea, has one of the largest ranges on Earth: nearly 60 °C between January and July.
Ocean currents add warmth
Currents carry heat across the oceans. The Gulf Stream and its extension bring warm water across the Atlantic, which is one reason Britain is much milder in winter than places at the same latitude in eastern Canada, such as Labrador.
Why the city may feel warmer
These values describe the area around the city, not one thermometer. Official city weather stations often read 1 to 2 °C warmer, especially for summer afternoons, partly because concrete, roads and buildings store heat: the urban heat island. The period matters too: the 2020s are already warmer than the 1981–2010 average.
Did you know?
Coastal cities in the tropics, such as Singapore, change by only a degree or two between their warmest and coolest months, while some Siberian towns swing by more than 60 °C.