Forecast: moderate coastal climates, variable temperatures inland

Ocean water and currents affect climate §. Because it takes far more energy to change the temperature of water than land or air, water warms up and cools off much more slowly than either. As a result, inland climates are subject to more extreme temperature ranges than coastal climates, which are insulated by nearby water.

Over half the heat that reaches the earth from the sun is absorbed by the ocean's surface layer, so surface currents move lots of heat. Currents that originate near the equator are warm; currents that flow from the poles are cold.

Highs and lows, coastal vs. inland §

                  (low)    (high)   (*N)
City               Jan      July    latitude

1)  Los Angeles    64*F     81*F     34.0 
                   18*C     27*C
2)  Little Rock    50*F     90*F     34.5
                   10*C     32*C

3)  Seattle         4*F     72*F     47.5
                    7*C     22*C
4)  Bismarck       18*F     82*F     47.0
                   -8*C     28*C

5)  London         45*F     73*F     51.5 
                    7*C     23*C
6)  Warsaw         32*F     75*F     52.5 
                    7*C     24*F

7)  Belfast        43*F     64*F     54.0
                    6*C     18*C
8)  Moscow         16*F     73*F     56.0 
                   -9*C     23*C

9)  Tokyo          46*F     82*F     35.0
                    8*C     28*C
10) Kabul          36*F     88*F     35.0
                    2*C     31*C
11) Beirut         63*F     90*F     34.0
                   17*C     32*C

Why is snow rare in London but common in Boston? When the warm Gulf Stream moves Caribbean heat to the North Atlantic, the water cools and releases a tremendous amount of heat into the atmosphere. Winds blowing west to east carry this moist warmth toward Europe §.

The Gulf Stream as drawn by Benjamin Franklin (left) and a satellite-derived sea surface temperature map of the Gulf Stream (right)

London (latitude 51.5 degrees North)
average annual precipitation - 23.8 inches (60.4 cm) record snowfall - 8 inches (20 cm) during one day, March 1947

Boston (latitude 42.3 degrees North)
average annual precipitation - 43.8 inches (111 cm) record snowfall - 23.6 inches (60 cm) during one day, February 1978

More Information

Ocean Planet Exhibition Floorplan

gene carl feldman ( (301) 286-9428

Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)