Hi Thomas, typically Ecuador’s coast is mostly overcast. But the most amount of sunshine (I am told) and do not know if this is proven or anecdotal data is at Playas — a beach town between Guayaquil and Salinas. And on the northern coast between Bahia de Caraquez and Pedernales.
In the northern Sierras (Quito and Imbabura) we get a lot of sunshine during the day. When it does rain, that usually happens in the late afternoon. I say “usually” because you have always have the odd day where it rains all day. But you can have that at the coast, too.
I hope this helps.