The climate of the Cocos (or Keeling) Islands, a territory of Australia in the Indian Ocean south of the equator, is tropical, with a hotter period from December to March, during which the maximum temperature hovers around 29/30 °C (84/86 °F), and a relatively cool period from June to October, during which the maximum temperature drops to around 27/28 °C (81/82 °F). The warmest months, albeit slightly, are February and March. The temperature is very stable, and it practically never gets either cold or very hot.
Here are the average temperatures of West Island.
Average temperatures - West Island

West Island	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
West Island	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	24	25	25	25	25	24	23	23	23	23	24	24
Max (°C)	29	30	30	29	28	28	27	27	28	28	28	29
Min (°F)	75	77	77	77	77	75	73	73	73	73	75	75
Max (°F)	84	86	86	84	82	82	81	81	82	82	82	84

The relative humidity is always high, but the heat is tempered by the trade winds, which blow throughout the year, with a greater intensity in the coolest months (July and August), and a lower intensity in the warmest months (February and March).
Rainfall is abundant, around 2,000 millimetres (79 inches) per year; there is no dry period, even though the rains are more abundant from January to July, when they swing around 200 mm (8 in) per month, with a maximum in March and April. The least rainy period goes from September to November, when the rainfall amount is lower than 100 mm (4 in) per month. The rainfall records, however, are high even in the months that are generally less rainy, which means that during some years the rains do not follow the same pattern.
Here is the average precipitation.
Average precipitation - West Island

West Island	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
West Island	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	190	160	230	230	190	200	210	130	80	70	90	110	1890
Prec.(in)	7.5	6.3	9.1	9.1	7.5	7.9	8.3	5.1	3.1	2.8	3.5	4.3	74.4
Days	11	12	15	14	14	16	16	13	10	8	8	8	145

There's no shortage of sunshine even in the wettest months, because the tropical rains occur mainly in the form of downpour or thundestorm, so they do not last long, however, the sun shines more often in the driest season.
The Cocos Islands can be affected by tropical cyclones of the southern Indian Ocean, whose season runs from November 1 to May 15, although they are more frequent from November to March.



For swimming, the sea is warm all year round, as you can see in the following table.
Sea temperature - Cocos Islands

Cocos Islands	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cocos Islands	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	28	28	28	28	28	28	27	27	27	27	27	27
Sea (°F)	82	82	82	82	82	82	81	81	81	81	81	81

The best time to visit the Cocos Islands corresponds to the months of September and October, being on average the least rainy; however, some showers should be taken into account also in this period. August is typically an acceptable month as well, although it's a bit more rainy.


All year round, light clothes, a scarf for the breeze, a light sweatshirt for the evening, light raincoat or umbrella, especially in the rainy season.