Portugal is composed by a mountaineous interior, and a coastal plain in the west that widens significantly from north to south. In the northern interior, broad flat-floored river valleys separate the main southwest-trending mountain ridges. The highest ridge is the Serra da Estrela in central Portugal. The Tagus River flows across Portugal from east to west. The mountains north of the Tagus are high, with about 80% of the land more than 400 m above sea level and summits exceeding 1,200 m. South of the river, the land is lower and more gently rolling with only 3% of the land higher than 400 m above sea level and peaks in the Serra de Monchique, the highest mountains in the south, under 915 m.
Portugal has a unique variant of the typical Mediterranean climate, the northern areas being wetter than average with only a short dry season and the south approaching subtropical, semiarid conditions. Along the coast the mean monthly temperatures range, according to latitude, from 9°C to 12°C in January and from 20°C to 24°C in July. Winds from the Atlantic moderate temperatures throughout the year. Frosts are rare in the north and virtually unknown in the south. Inland, mean temperatures fall by 3°C or 4°C in winter and, except on the highlands, rise appreciably in summer. The average yearly precipitation decreases from between 1,000 and 1,300 mm in the north to between 400 and 600 mm in the south. Most rain falls during the cooler months. Relative sunshine duration ranges from 50 to 60% to the north of the Tagus river to values above 60% to the south of that river.
Total population is 9,865,114 (World Factbook, July 1996 est.). Population densities are highest in the northern coastal areas and decrease inland and towards the south. In all, about 80% of the total population is concentrated north of the Tagus River, where habitable areas are densely settled with towns, villages, and farmsteads. By contrast, areas south of the Tagus are sparsely populated, and the landscape, is one of widely spaced towns and villages and large, isolated farmsteads. The two largest cities are Lisboa and Porto. Lisboa, with well over 1,000,000 inhabitants in its metropolitan area, is the capital and the main industrial, commercial, and financial center.
Stations from the IDMP Network measure both daylight and solar radiation.

IDMP Network/Lisboa

Lat.: 38°45' N
Long.: 9°08' W
Height above sea level: 106 m

Eng. Antonio José SANTOS
Laboratorio Nacional de Engenharia Civil
101 Avenida do Brasil
P-1799 Lisboa, Portugal
Tel: +351 1 84 82 131
Fax: +351 1 84 97 660
E-mail: asantos@lnec.pt

Clock Time: GMT. Summer time shift (GMT+1), from last Sunday in March,
to Saturday before last Sunday in October.

Presently there are no approved national laws, standards or codes of practice on lighting or daylighting. CIE standards and recommendations are currently adopted instead.

  1. "O clima de Portugal" - Fascículo XLIX. INMG. LISBOA, 1991. ("The Portuguese Climate" - Publication N°49. INMG. LISBON, 1991)

    Volume 1, 1a Região : "Normais Climatológicas da Região de Entre Douro e Minho e Beira Litoral"

    Volume 2, 2a Região : "Normais Climatológicas da Região de Ribatejo e Oeste"

    Volume 3, 3a Região : "Normais Climatológicas da Região de Trás-os-Montes e Alto Douro e Beira Interior"

    Volume 4, 4a Região : "Normais Climatológicas da Região de Alentejo e Algarve"

    Volume 5, 5a Região : "Normais Climatológicas da Região dos Açores"

    Volume 6, 6a Região : "Normais Climatológicas da Região da Madeira"

    This publication presents 30 year averages (1951-1980) for 132 meteorological stations (106 in Continental Portugal and 26 in Madeira and Açores Islands) of the following monthly and yearly mean values: Atmospheric Pressure, Air Temperatures, Relative Humidity, Nebulosity, Sunshine Duration, Precipitation, Evaporation, Wind Speed and Direction, Number of days with mean nebulosity above eight and below two, and other absolute frequencies of several meteorological occurrences.

  2. "Temperaturas Exteriores de Projecto e Números de Graus-Dias". INMG, LNEC. LISBOA, 2e Ediçào, 1995.("External Design Temperatures and Number of Degree Days". INMG, LNEC. LISBON, 2nd ED., 1995.).

    This publication presents summer and winter external design temperatures and heating and cooling degree days for a comprehensive number of localities all over the country, including Açores and Madeira islands. The methods adopted in the calculations are also summarized.

  3. "Atlas Climatológico de Portugal Continental". Edição Preliminar. INMG. LISBOA, 1974. ("Climatological Atlas of Continental Portugal". Preliminary Edition. INMG. LISBON, 1974).

    The maps that constitute the Atlas, describe graphically the climatic characteristics of Continental Portugal. The quantities included are monthly and yearly averages of basically the same quantities for publication A, but referring to the period 1931-1960.
Instituto Electrotécnico Português
Rua de S. Gens, 3717
4460 Senhora da Hora
Tel: +351 2 953 57 08
Fax: +351 2 953 05 94


More information is available at Amadeus or the Electric Library

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