Spanish word: Invierno, El Invierno.

el invierno: winter, rainy season (in the tropics where there are typically two seaons, a wet season and a dry one).

Ejemplo: El secreto para estar cómodo en cualquier actividad al aire libre durante el invierno es el estar seco y caliente.

The secret to being comfortable in any outdoor activity during the winter is to be dry and warm.