What is the weather going to be like during my holiday?
The answer is almost always the same: If you are going to south Gran Canaria's resorts, it is very likely to be sunny every day. Yes, even in the winter. Yes, even though your weather app says it is going to be cloudy. Yes, even in January. And in February, etc.
Obviously it does sometimes rain in Gran Canaria, even in the sun-baked south, and there are occassional cloudy days.
To check for these rare rain and clouds there is no point using generic weather apps because they use data that averages out the weather and temperature across Gran Canaria.
This means that the forecast for Puerto Rico and other resorts includes weather and temperatrure predictions for inland and highland areas that are cooler and cloudier.
So, instead of believing your current weather app use the Spanish weather service website called the AEMET. It's website has detailed and very accurate forecasts for individual resorts, town and even beaches.