Weather: Indonesia, Papua New Guinea, Solomon Islands
What Indonesia lacks in longitude, it makes up for in its vast east–west spread, extending over 4800km/3000 miles (and even further if you include Papua New Guinea). The volcanic peaks of Indonesia ensure that the main temperature differences are tied to elevation. As in Malaysia, anticipate a drop of roughly 6°C/11°F for every 1000m/3300ft, with very little difference between the months of the year. Avoiding the rainy season is a more challenging task – and you may want to avoid it, since it brings most of Indonesia more than 1500mm/59in of water. The southwestern chain of islands, including Bali and Timor, are drier than their northern counterparts. In general, destinations along south and west slopes – the west coast of Sumatra, for example – get their heaviest rains from May to October. North-facing locales – such as the bulk of Sumatra, northern Java and Sulawesi – are wettest from November to April. The same holds true as you move east and south into Papua New Guinea and the Solomon Islands, where the Australian monsoon dominates. The soaring peaks on Papua New Guinea can be incredibly cold, with snow clinging to the highest ones. Some Indonesian islands tend more toward a two-peak equatorial pattern, with wet spells from March to May and near the year's end, plus ample rain even during the dry periods. There are infinite variations to these guidelines, as the array of islands in and near Indonesia can produce small-scale blocking of monsoon flow in either direction. It's worth checking with a reliable local source on the island(s) you plan to visit. El Nino years tend toward drought across Indonesia during the November-to-April season, exacerbating the risk of forest fire and smoke.