Map from Google - Los_Roques

Los Roques, coral archipelago in the Caribbean Sea, belonging to Venezuela and equipped with beautiful beaches, has a tropical climate, hot all year round, but also semi-arid. The temperatures vary little throughout the year, however, they are a bit lower from December to February, when daytime temperatures are around 29/30 °C, and higher from July to October, when they reach 31/32 °C.
Here are the average temperatures.
Average temperatures - Los Roques
Los RoquesJanFebMarAprMayJunJulAugSepOctNovDec
Los RoquesJFMAMJJASOND
Min (°C)212122232424242424232322
Max (°C)293031313231313232323130

There are essentially three seasons, though not marked. From November to mid-February, and especially in November and December, the northeast trade winds bring quite frequent rains, though generally not abundant, in the form of brief showers, which soon give way to the sun. From mid-February to May it's the driest period, with mostly clear skies and sporadic rains. From June to October it's usually the wettest period in the Caribbean, but in Los Roques and other southern islands, known as Leeward Antilles, it's felt little, so that there are long periods of good weather, alternating with others in which showers and thunderstorms, usually not abundant, can erupt.
So the rainfall, at least in quantity, is very scarce, given that it amounts to 305 millimetres per year; the only month in which it exceeds 50 mm are November and December.
Here is the average precipitation.
Average precipitation - Los Roques
Los RoquesJanFebMarAprMayJunJulAugSepOctNovDecYear
Los RoquesJFMAMJJASONDY
Prec. (mm)301510101015252025306055305
Days1084567910971213100

The wind blows steadily all year round, tempering the heat.
The amount of sunshine in Los Roques is good all year round, as clear skies prevail. At noon the sun reaches the highest point in the sky, that is the zenith, twice, around 20 April and 20 August, and remains close in the summer months, so you need a suitable protection.

Los Roques is located in the southernmost part of the hurricane belt, which entails that it is rarely affected, but contrary to popular belief, it is not entirely safe. Hurricanes occur from June to November, but are more likely from August to October.

Cayo de Agua

For swimming, the sea is warm all year round, as the temperature varies from 26 °C in the period from January to April, to 28 °C from August to November.
Here are the average sea temperatures.
Sea temperature - Los Roques
Los RoquesJanFebMarAprMayJunJulAugSepOctNovDec
Los RoquesJFMAMJJASOND
Sea (°C)262626262727272828282827

When to go

Although the weather tends to be favorable throughout the year, the best time to go to Los Roques, for swimming and sunbathing, runs from mid-February to May, being the driest and out of the period of hurricanes, which, however, are very rare. The weather is almost always good even in summer, but there may be some showers, usually brief. Even in November and December the sun shines, but rainfall is quite frequent, though usually of short duration; sometimes however, thunderstorms may be stronger than usual.