Including a description of the weather and climate of Belize, Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica.
There are seven small countries in the narrow isthmus of Central America, between the southern border of Mexico and the northern border of Colombia. From north to south these countries are: Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, and Panama.
Together these countries have an area of 470,000 sq km/180,000 sq mi, a little larger than the state of California and about twice the size of the United Kingdom.
The area lies between 18° and 7°N and between 77° and 95°W. The whole area is within the tropics and, because of the narrowness of the isthmus, is strongly influenced by the ocean, with the result that almost everywhere the climate is tropical with abundant rainfall.
At its narrowest point the isthmus is only about 80 km/50 mi across, but in Nicaragua and Honduras it widens to about 560 km/350 mi. A chain of mountains, ranging in height from 1,200 m/4,000 ft to 4,000 m/13,000 ft, runs approximately through the centre of the isthmus.
Climate and weather in all these countries are broadly similar and are described here. Only brief notes amplifying this description, with a note of any local peculiarities, are given for individual entries.
Situated well within the tropics, but north of the equator, all these countries have a typically tropical climate with high temperatures around the year at low altitudes. Temperatures are significantly modified by altitude and a simple and useful threefold division into climatic zones can be made using the local terms: tierra caliente, tierra templada, and tierra fria.
In the tierra caliente, from sea level up to about 900 m/3,000 ft, temperatures are hot throughout the year. The tierra templada from 900 m/3,000 ft to 1,800 m/6,000 ft has cooler temperatures, but many tropical or subtropical crops such as coffee are grown. Here there are many local differences in the amount of rainfall, depending on altitude and the aspect of the mountains in relation to the prevailing winds.
The tierra fria, from 800 m/6,000 ft to 3,000 m/10,000 ft, is limited in extent, but here conditions are quite cool and typical of temperate latitudes. Frost and snow may occasionally occur but the mountains are not high enough to carry permanent snow.
Over most of this region the season of maximum rainfall is between May and September, the period of high sun in the northern hemisphere. Places on the eastern coast, or the Caribbean shore, tend to be rather wetter, and to have a longer rainy season, than those on the Pacific coast to the west.
In some places on the Caribbean shore there is a tendency for a double rainy season and all months have significant rainfall; this is well illustrated by the table for Belize City. Even in the narrow isthmus of Panama, annual rainfall at Cristobal on the Caribbean coast is double that at Balboa Heights on the Pacific.
Some of the wettest places in this region are where mountains face the persistent northeast to easterly trade winds which blow onshore for most of the year.
Another significant feature of the weather and climate of Central America is the liability of most of the area to suffer hurricanes between June and November. These severe tropical storms develop well to the east of the Caribbean in the central Atlantic at about 5° to 10°N.
The most usual track of these disturbances is across the West Indian islands, after which they curve north or northeastwards. The coastal regions of Central America are affected less frequently and less severely than the islands farther east, but those hurricanes which reach the mainland can produce very heavy rainfall and their strong winds can cause extensive damage.
Costa Rica and Panama are rarely affected by them but the remaining countries can experience hurricanes which, even when weakening and losing the more violent winds, can add appreciably to the rainfall in the months August to October. The Pacific coastlands of Central America are also occasionally affected by less violent tropical storms which develop in the eastern Pacific Ocean.
In the lowlands of the tierra caliente, temperatures remain high in all months with a very small daily range of temperature. Near the coast humidity is also high and the principal relief from this perpetually warm, humid climate is the daily sea breeze.
Extremely high temperatures are never recorded on the coast and midday temperatures may even be higher inland than in the tierra templada. Inland and at higher levels there is a much larger daily range of temperature and the nights are pleasantly cool.
This can be seen by comparing the average and extreme temperatures for Guatemala City or San Salvador with those for Belize City in the tables for the respective countries.
Sunshine amounts are quite high throughout the year in most of Central America. Average daily sunshine hours range from six to eight in the wetter months to as many as ten hours during the dry months, even though this is the time of low sun.
Costa Rica and Panama have a rather cloudier climate with more frequent rain, so that here the sunshine hours range from four to five in the wettest months to eight or nine in the driest season.
Many areas in Central America had a bad reputation in the past for fever and tropical diseases. The climatic conditions of the lowlands encouraged malaria and yellow fever, but these have largely been eradicated and were only indirect effects of the climate.
The climate itself, although sultry and oppressive for much of the year in the wetter lowlands, is not particularly unhealthy. Indeed, in the drier areas and in the hills it is pleasant and sunny for much of the year.
Panama itself occupies the narrowest part of the Central American isthmus. It lies between 7° and 9°N and owes its existence as an independent state to the cutting of the Panama Canal by the United States; previously it was part of Colombia.
Although there are areas of lowland on both the Caribbean and Pacific coasts, much of the interior is hilly with some mountains rising above 3,300 m/11,000 ft. Within this small area, therefore, are examples of the three climatic zones described above.
The table for Balboa Heights is representative of the Pacific coast. The lowlands on the northern or Caribbean coast are almost twice as wet but temperatures are almost the same. Panama is about the same size as the state of Maine.
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