Answer:
"It is windy."
In Spanish: Está ventoso.
Step-by-step explanation:
The translation of windy is ventoso. When referring to the weather, it's very common in Spanish to use the verb "estar" followed by the adjective in the masculine form, for example:
Está soleado: it's sunny.
Está fresco: it's cold.
Está ventoso: it's windy.
Está nublado: it's cloudy.
Está lluvioso: it's rainy.