The Tenerife weather is one of the most pleasant in the world. Winters are very mild and summers are hot but not overpowering with the average temperatures seldom dropping below 15ºC or going above 30ºC. The temperature is usually a few degrees cooler in the north (where the capital of Santa Cruz is). Mount Teide is Spain's highest mountain at 3800m is colder (remember 1 degree F drop for every 300'!) with snow on top in winter.
There is very little rainfall in Tenerife in general with extremely dry summers especially in the south of the island, but from October to March there can be occasional showers in the north of the island.
Be sure to use plenty of sun cream no matter which season or which part of the island you visit as the sun is almost always shining and is very powerful.
In winter the temperatures are still very pleasant and this combined with the many clear sky and sunny days allow locals and tourists alike to spend plenty of hours outdoors.

Average rainfall in the south of the islands:
