The Republic of Costa Rica

by Gustavo Niederlein

The climate of Costa Rica depends on its situation in the tropics, on the position of the sun at different times of the year, and on the topography, but, owing to the narrowness of the country and its situation between the two great oceans, it is well-tempered by the alisios (northeast trades) and other winds.

I begin this chapter with the following table which gives the

Meteorological Conditions in San José During the Year 1896.

	Temperature in C.°			Evaporation.	Humidity.	Atm’sph’ic Pressure.
	Max.	Min.	Average.	Average.	Average.	Average in mm.
				Per cent.
January	28.5	10.8	18.60	26.97	78	665.86
February	31.8	10.5	19.24	33.97	74	665.39
March	32.4	12.2	19.84	42.77	70	665.38
April	28.4	14.8	20.13	19.65	84	664.87
May	29.2	15.8	20.10	19.84	83	665.32
June	28.8	14.9	20.32	18.67	84	665.09
July	29.2	15.8	20.10	19.84	83	665.32
August	29.2	14.7	20.17	22.81	82	664.38
September	26.6	14.4	19.97	17.87	85	664.83
October	28.4	14.8	20.13	19.65	84	664.87
November	29.0	14.2	19.78	19.93	84	664.70
December	27.7	11.9	19.30	25.29	80	665.36
Average	28.71	13.73	19.81	23.94	81	665.21

First Half of 1897.

	Temperature in C.°			Evaporation.	Humidity.	Atm’sph’ic Pressure.
	Max.	Min.	Average.	Average.	Average.	Average in mm.
				Per cent.
January	29.5	13.1	19.25	30.77	78	665.53
February	31.9	8.2	19.78	44.89	70	666.52
March	31.7	10.9	20.51	36.68	72	665.70
April	32.7	12.2	21.02	36.80	74	665.59
May	30.3	14.0	20.52	24.29	82	665.52
June	29.3	15.5	20.40	16.40	85	665.32

The average atmospheric pressure of San José, the capital of the country, is 665.21 mm. The maximum occurs regularly during the months from October to March inclusive, at nine o’clock a. m., and during the rest of the year at eleven o’clock p. m. The minimum occurs always in the afternoon at four o’clock during the first eight months of the year, and at three o’clock during the last four months.

The prevailing wind is from the northeast, or, better, north-northeast and east. During August, September and October an increase of the northwest winds causes the heavy rains of that season. West-northwest and northwest winds blow also from May to August.

The daily variation of winds is generally as follows:

At seven a. m. the most frequent winds blow from S. E., to N. E.; at ten o’clock a. m. from E. to N. N. E; at one o’clock and at four o’clock p. m. from E. N. E. to N.; from seven o’clock p. m. the movement is retrograde. The velocity is least from seven to ten o’clock a. m., and most from one to four o’clock p. m.