Question

Traducir a negativo tomorrow it is going to rain a lot

Answer 1

Solo basta con ponerle un (Not)

Tomorrow it is not going to rain.

O tambien puede ser: Tomorrow It's not going to rain.

O: Tomorrow It isn't going to rain.

Aunque mi manera de escribirlo seria: It's not going to rain tomorrow.

Pero tu usa una de las tres primeras, saludos desde Venezuela!