Gran Canaria is known as the "continent in miniatura" for its diversity with larger historic towns and cities to the north, typical local villages, forests and resevoirs spread throughout the mountains in the center and of course the well known tourist resorts and beaches to the south. In addition and although the island is only 50km long/wide there's a climate of "eternal spring" in the north thanks to the Atlantic trade winds (arguably the best climate in the world) and all-year-round summer in the south as it faces the Western Sahara little more than 200km away.
Most visitors to the island head for the southern coast thanks to almost 52 weeks of sunshine and beach-worthy weather down there throughout the year; winter here is high-season, there is no off season. Those curious to get out and about and see more of the island will usually book an island tour for the day or perhaps hire a car for a day or two but there's another option especially at certain times of the year when major events are taking place.
During the winter season each year, usually during February, Las Palmas city in the north is home to one of the biggest Carnivals in the world lasting 3 weeks. The main events can see up to a half million people in the streets for the main parade and night time parties whilst several nights per week and daytimes at the week-end will see various competitions taking place attracting several thousands. The downside to booking a week or two in the north of the island in winter is the sunshine isn't guaranteed. Whilst your entire stay may see clear skies, sunshine and temperatures of 25C you may also have several days of cloud, some rain and temperatures around 20C. If you'd like a more cultural holiday to the island but at the same time it's essential to have a few days to unwind on the beach or by the pool then another option would be a two-resort holiday, a few days or a week in the north followed by the same in the south. There are modern, air-conditioned buses running semi-direct services every hour or more between Las Palmas, the airport and the major resorts in the south with the journey from north to south taking less than an hour. More details and times for bus services can be found here. You could also hire a car for around 20 euros a day or 80 euros for a week and of course a taxi would be the easiest but you'd also be looking at around 80 euros for the trip.
Las Palmas is one of the highest rated city/beach destinations in Europe on Tripadvisor, home to three blue-flag beaches, a 500-year old historic quarter, outstanding duty-free shopping all over the city and of course major cultural events and concerts throughout the year such as Carnival. Read more about Las Palmas here.
Carnival 2019 dates are being announced as I write 15 February to 10 March with main night-time events taking part in Parque Santa Catalina :- Carnival Queen on March 1st, Drag Queen competitions on March 2nd and 4th and 9th March bieng the biggest day with the main parade during the afternoon the street parties into the night. More info in Spanish here.