Climate (Giambelli, 1995)
The islands lie close to the equator and are subject to the west and east monsoon cycle. As in Bali, the year is basically divided into two periods: a first period that runs from the end of April or beginning of May, (sasih jesta according to the Balinese lunar calendar) to the end of September (sasih katiga) characterised by a hot and dry climate called masan panes.
Image right: Birding Observation Site at Tembeling (by author Godi Dijkman)
During this period the prevailing winds reaching Bali and Nusa Penida come from the south-east and are mainly dry. Precipitation is at a minimum, farming activities nearly stop and tend to be limited to the harvest of beans or peanuts and the search for fodder for the animals (cows and pigs).
There follows a second period from the beginning of October (sasih kapat) to the end of March (sasih kesanga), which is characterised by regular precipitation called masan ujan (rainy season). At the beginning of October the prevailing winds change and they reach Bali and Nusa Penida from the south-west. These winds bring to the islands the western monsoon with its rain. During this period in Nusa Penida all the relevant farming activities begin, such as the planting of maize, of dry rice, beans and cassava. Because of the dry environment farmers tend to plant all crops at the beginning of the rainy season so as to maximise the chances of a successful harvest.
Notwithstanding the proximity to the equator, the level of precipitation in Nusa Penida is considerably lower than that registered in the central areas of Bali and comparable only to the Balinese area of bukit. The average rain fall of Nusa Penida 1989, compared with the areas Klungkung and Denpasar, was according to statistical sources: Nusa Penida 1.169.0 mm; Klungkung 2.127 .01 mm; Denpasar 2,081.6 mm.
The lower levels of rainfall in Nusa Penida may be explained both my the island's low profile and by its geographical position since Nusa Penida is partly shaded by Bali's major mountains which virtually block the western clouds from moving eastward during the period of the western monsoon.
The general level of rainfall is dependent on hemispheric climatic conditions and 1990 was one of the worst years for Nusa Penida as far as shortage of rainfall was concerned. In that year there was a three months lag in the arrival of the western monsoon. The delay had a severe impact on the local economy, forcing the postponement of all seasonal planting and causing the loss seeds. The drought was so severe and the farmers' anxiety for the dying crops so intense that rituals for the calling of rain were performed in two of the major temples of the island, Pura Segera Penida and Pura Sahab Batumadeg. The first rain fell at the end of December. The prolonged drought caused the end of all deomestic water supplies forcing people to walk long distances to the rare wells and springs in search of water.
- Giambelli, Rodolfo A. - Reciprocating with Ibu Pretiwi. Social organisations and the importance of plants, land and the ancestors in Nusa Penida, Department of Anthropology Research School of Pacific and Asian Studies The Australian National University. Canberra 1995, p.2-4