The gemora says that the late rain is called "malkosh" because it breaks the hardness of the yiden when it doesn't come by doing "teshuva". See Rashi. Why should this be true if the early rains have already come? If anything, this makes more sense with the "yoreh" when it hasn't come by a certain date and there is still a drought!
Allen Schuldenfrei, Baltimore, Maryland USA
The Yoreh is a light rain and does not actually fulfill the needs of the crops, and thus the late rain is still vitally importantly.