Cilacap Regency
Cilacap Regency (Indonesian: Kabupaten Cilacap) is a regency situated in the southwestern portion of Central Java province, Indonesia, bordering the Indian Ocean to the south.[1] It spans an area of approximately 2,250 square kilometers, including the offshore Nusakambangan Island, and recorded a population of 2,046,392 residents in recent official statistics.[2][3] The administrative capital is the coastal town of Cilacap, which functions as a significant deep-water port facilitating maritime trade and industrial logistics on Java's southern shoreline.[4] Economically, the regency is dominated by the energy sector, anchored by the Pertamina Cilacap Refinery—the largest in Indonesia with a processing capacity of 348,000 barrels per stream day—producing fuels, petrochemicals, and increasingly sustainable aviation fuel from feedstocks like used cooking oil.[5][6] Complementary industries include fisheries, agriculture, and power generation, while environmental features such as the Segara Anakan Lagoon support biodiversity but face pressures from industrial expansion and sedimentation.[7] The regency's per capita gross regional domestic product reached Rp 65.95 million in 2023, reflecting robust industrial contributions amid ongoing efforts to integrate green refining technologies.[7][8]
Geography
Location and Physical Features
Cilacap Regency occupies the southwestern extremity of Central Java Province in Indonesia, positioned between approximately 108°04'30" and 109°03'30" east longitude and 7°03'00" and 7°45'20" south latitude.[9] It borders Brebes, Banjarnegara, and Kuningan regencies to the north, Kebumen Regency to the east, and Pangandaran, Ciamis, and Banjar regencies in West Java to the west, with the Indian Ocean forming its southern boundary.[10] The regency spans 2,253.61 square kilometers, rendering it the largest by area in Central Java, and includes the offshore Nusakambangan Island.[9] The physical landscape of Cilacap Regency exhibits diverse topography, transitioning from coastal lowlands and plains along the southern shoreline to undulating hills and steeper mountainous regions in the northern interior.[11] Northern areas feature hilly morphology with slopes ranging from gentle to steep, influenced by the broader Javanese terrain.[11] Southern coastal zones display prograded formations characterized by parallel sandy beach ridges interspersed with marshy valleys, shaped by sedimentary deposition from ocean currents and river outflows.[12] Nusakambangan Island, a narrow limestone outcrop parallel to the mainland, shelters the coastal harbors from monsoon swells.[13]Climate and Weather Patterns
Cilacap Regency features a tropical rainforest climate (Köppen Af), marked by consistently warm temperatures, high humidity, and substantial year-round rainfall without a prolonged dry season. Average high temperatures range from 27°C in August to 29.5°C in March, while lows vary between 23°C in July and August and 25.4°C in January and May; extremes rarely drop below 22°C or exceed 32°C.[14][15] The maritime influence from its southern coastal position on Java moderates temperature fluctuations, maintaining relative stability across seasons. Precipitation patterns exhibit a wetter period from late October to early May, when over 41% of days feature rain, peaking at approximately 318 mm in November; the relatively drier phase from May to October sees reduced totals, with August averaging 51 mm. Annual rainfall accumulates to around 2,000–2,700 mm, supporting lush vegetation but contributing to frequent cloud cover (up to 86% overcast in January) and occasional flooding risks during intense monsoon activity.[14][16] Humidity levels remain oppressively high year-round, often exceeding 80% and reaching 100% muggy conditions consistently, exacerbating the perceived heat. Wind patterns show calmer conditions (averaging 10 km/h) from November to May, with stronger southeasterly trades (up to 17 km/h) during the drier months, particularly August. These features align with broader Central Java trends, though local topography and industrial activity near Cilacap may slightly influence microclimatic variations in rainfall distribution.[14]| Month | Avg. High (°C) | Avg. Low (°C) | Precipitation (mm) |
|---|---|---|---|
| January | 29.3 | 25.4 | 150 |
| February | 29.2 | 25.3 | 139 |
| March | 29.5 | 25.3 | 152 |
| April | 29.1 | 25.3 | 145 |
| May | 29.1 | 25.4 | 143 |
| June | 28.1 | 24.6 | 68 |
| July | 27.3 | 23.8 | 51 |
| August | 27.0 | 23.0 | 36 |
| September | 27.3 | 23.1 | 51 |
| October | 28.0 | 24.0 | 94 |
| November | 28.5 | 25.1 | 149 |
| December | 28.9 | 25.3 | 139 |