The Climate of Indonesia

Indonesia is a large country situated around the equator, consisting of several large land masses eg. Sumatra and Kalimantan, and hundreds of smaller islands. Many areas are volcanic and very mountainous, some exceeding 10 000ft (3000m) in height. As a result there are many sharp local differences of climate within the country; temperatures are much lower in the hills, and the season and amount of maximum rainfall varies with the different exposure of the islands to the two main seasonal wind systems. From November - March, the country is dominated by the north monsoon, blowing from China; while May - September is the period of the south monsoon, which blows from the Indian Ocean and Australia. A transition period between the two monsoons may be observed in April and October, during which the winds are light and variable in direction. Other than the cooler temperatures found in the mountains, Indonesia's weather and climate are typical of tropical, equatorial regions.

Rainfall is well distributed round the year and is usually heavy and accompanied by thunder. South-facing coasts and islands south of the equator tend to be wetter during the period of the south monsoon, while north-facing coasts and the northern islands are wetter during the period of the north monsoon.

Although rainfall is heavy, there is also a lot of sunshine, averaging 4-5 hours a day during the wetter months, and 8-9 hours a day in the drier months.Temperatures are high all year round with little difference from month to month. The daily range of temperatures is small in coastal areas, but this increases inland and in the mountains.

The extreme southern islands, such as Timor, may be affected by strong winds associated with tropical cyclones, which occur in the southern hemisphere from Nov - March. Local wind squalls can also occur during thunderstorms. The cooler nights inland and the daytime sea breezes and strong monsoon winds afford the chief relief from the heat and humidity on the coast.
 

	Jakarta Month Rainfall(mm) Temperature (Celsius) Ave. Monthly Ave. No. of Days with 1mm Average Daily Lowest Recorded Highest Recorded Min Max Jan 304 19 23 29 21 34 Feb 300 16 23 29 21 33 Mar 210 15 23 30 21 33 Apr 148 10 24 31 21 33 May 110 9 24 30 21 34 Jun 96 8 24 31 19 34 Jul 67 6 23 31 19 34 Aug 42 4 23 31 19 35 Sep 69 6 23 31 20 36 Oct 111 9 23 30 21 37 Nov 142 12 23 30 20 36 Dec 201 15 23 29 19 34

	Medan Month Rainfall(mm) Temperature (Celsius) Ave. Monthly Ave. No. of Days with 1mm Average Daily Lowest Recorded Highest Recorded Min Max Jan 135 12 22 29 18 34 Feb 92 7 22 31 19 34 Mar 103 9 22 31 18 35 Apr 133 10 23 31 19 35 May 173 13 23 32 19 36 Jun 134 10 22 32 17 35 Jul 135 9 22 32 17 36 Aug 179 12 23 32 18 35 Sep 214 15 23 31 19 36 Oct 260 17 22 31 18 35 Nov 244 18 22 30 17 34 Dec 228 15 22 29 18 34

	Padang Month Rainfall(mm) Temperature (Celsius) Ave. Monthly Ave. No. of Days with 1mm Average Daily Lowest Recorded Highest Recorded Min Max Jan 152 15 23 31 21 34 Feb 258 13 24 31 22 34 Mar 308 16 23 31 21 34 Apr 361 18 24 31 22 33 May 317 13 24 31 21 34 Jun 306 12 24 31 20 34 Jul 275 11 23 30 21 33 Aug 349 15 23 31 20 33 Sep 152 17 23 30 20 34 Oct 496 20 23 31 21 33 Nov 519 21 23 30 21 34 Dec 482 19 23 30 21 33

	Balik Papan Month Rainfall(mm) Temperature (Celsius) Ave. Monthly Ave. No. of Days with 1mm Average Daily Lowest Recorded Highest Recorded Min Max Jan 202 14 23 29 21 33 Feb 177 13 23 30 22 33 Mar 230 16 23 30 21 33 Apr 209 13 22 29 22 32 May 230 14 23 30 22 32 Jun 195 12 22 29 18 32 Jul 183 12 21 28 19 29 Aug 165 11 23 29 21 30 Sep 139 10 22 29 19 31 Oct 134 9 23 30 20 32 Nov 169 13 23 30 21 33 Dec 206 15 23 29 21 32

	Ujung Pandang Month Rainfall(mm) Temperature (Celsius) Ave. Monthly Ave. No. of Days with 1mm Average Daily Lowest Recorded Highest Recorded Min Max Jan 687 25 23 29 21 31 Feb 535 21 24 29 21 32 Mar 426 18 23 30 21 32 Apr 153 11 24 30 21 33 May 87 9 23 31 20 32 Jun 75 6 22 31 17 33 Jul 37 5 22 30 18 34 Aug 11 3 21 31 17 34 Sep 16 2 21 31 15 35 Oct 42 6 22 30 19 33 Nov 179 12 22 30 20 32 Dec 613 20 23 29 21 32