Download Climate: The Two Ports What is the climate of Cabo San Lucas and

Climate: The Two Ports
What is the climate of Cabo San Lucas and that of Nuku Hiva?
We can examine the concept of climate by examining average temperature and
precipitation conditions at Cabo San Lucas, Mexico (port of origin) and also at Nuku Hiva,
French Polynesia (port of destination). The numerical data were collected from and
crosschecked by information from several on-line climatic data repositories. We will examine
the numerical data, graphs of climate data (climographs), and explore the geographic settings of
each location that help explain the graphed numbers.
Climate and Geography of Cabo San Lucas, Mexico
Climate Data for Cabo San Lucas
Avg. Temp (F)
64 66 68.5 72
Precip (in)
0.2 1.1
0
0
Month
J
F
M A
75
0
M
80
0.2
J
84.5
0.4
J
85
1.2
A
84.5
1.4
S
79
0.6
O
90
73
0.5
N
67.5
1.1
D
30
80
25
70
60
20
50
15
40
10
30
20
5
10
0
0
J
F
M
A
M
J
Avg. Temp (F)
J
A
S
O
N
D
Precip (in)
Cabo San Lucas is located on the southern tip of the Baja Peninsula, on the Pacific coast
of Mexico. This coastal area is dominated throughout the year by a cold current flowing south
along the margin of the Pacific, combined with cold, upwelling water along the peninsula; both
currents are influenced by the westerly wind belt. Although it is warm in the air, the cool water
means less evaporation occurs than people might expect in a coastal location. In the spring, as
the sun migrates north toward the Tropic of Cancer, the drying effects of the subtropical high
pressure belt also migrate north; notice that precipitation does not occur in the spring months.
Precipitation picks up in the summer months as local winds undergo a reversal, or monsoon, and
flow onshore. This reversal of wind brings warm, moist, tropical air from the south into the
region. These southerly winds flow up the mountains that lie to the north of Cabo San Lucas,
lifting the moist air and enhancing rainfall. This is known as orographic lifting and orographic
precipitation (mountain lifting and precipitation), which works much in the same way as air
flowing across the mountains of the coastal Pacific Northwest in the United States. There is a
warm season that occurs following the high-sun June solstice and a cool season that occurs
following the low-sun December solstice.
These average conditions of temperature and precipitation place Cabo San Lucas in a
general climate category of tropical desert, with an average surface temperature of 75 degrees
Fahrenheit and total annual precipitation of 6.7 inches.
Climate and Geography of Nuku Hiva, French Polynesia
Climate Data for Nuku Hiva
Avg. Temp (F)
81.5 81.5 81.5 81.5 80.5 80.5 78.5 78.5 78.5 79.5 80.5 81.5
Precip (in)
5
4
6
5
5
6
5
4
2
3
3
4
Month
J
F
M
A
M
J
J
A
S
O
N
D
90
30
80
25
70
60
20
50
15
40
30
10
20
5
10
0
0
J
F
M
A
M
J
Avg. Temp (F)
J
A
S
O
N
D
Precip (in)
Nuku Hiva is a volcanic island in French Polynesia (also known as the Marquesas
Islands). The weather station is located at the airport on the northwestern corner of the island.
Nuku Hiva’s location nearer to the Equator, and being an island surrounded by ocean,
contributes to its near-constant average temperature. The weather station receives rainfall
throughout the year which supports lush grasses and tropical trees. The weather station receives
less rainfall than it could, because it is in the rainshadow zone of a mountain ridge (of Mont
Tekao) that intercepts the prevailing winds and causes mountain uplift and precipitation to the
southeast of the weather station. Up the slopes of the mountain there is more rainfall and the
terrain more closely resembles that of a tropical rainforest than a tropical grassland; the mountain
causes rain to fall out of the rising air, and as the air descends the northwestern slopes of the
ridges towards the airport’s weather station, it dries out a bit and has less rain to drop on the
airport. Even so, it receives more annual rainfall than Seattle, Washington.
At the weather station found at the airport, the average temperature is 80 degrees
Fahrenheit and the total annual precipitation is about 52 inches. The general climate for the
island is tropical, but the landscape position determines whether grasses or trees dominate. If a
landscape is found on the windward side of a mountain, it gets more rainfall; if it is on the
leeward side of a mountain, it gets less rainfall.
Pacific Northwest Connection
The climatic conditions of both the Latitude voyages’ ports are influenced by
mountainous terrain. When wind blows air over mountains, it increases precipitation on the
windward side (where the wind comes from), and precipitation decreases on the leeward side as
the air descends to lower elevations, heats up, and dries out the landscape. We can see a
connection to the Pacific Northwest if we view the region from space.
From left to right in this satellite view, we are looking at a region that stretches from the
Olympic Peninsula of Washington on the left to the various mountain ranges of northern Idaho to
the left. At this latitude, our winds generally come from the west. Notice that the western slopes
of the Olympic and Cascades tend to be much greener than the areas located to the east of those
mountain ranges. The Columbia Plateau of Eastern Washington, Oregon, and Idaho is at a lower
elevation than the mountains that surround it, and is browner in color except where we find
irrigated croplands. More rainfall equals more vegetation, in general. The green landscapes pick
up again as we approach the mountain ranges that stretch along the eastern border of
Washington, due to uplift as the westerly winds encounter increasing elevation. If the mountain
elevations are high enough, year-round snowpack and glaciers form.
Elevation and topography are important elements of climate worldwide. Mountains and
mountain ranges interrupt atmospheric winds and influence the variability of precipitation.
Volcanic islands interrupt both winds and oceanic currents; volcanic islands are what we can see
of large mountains that extend up from the ocean floor.