Comentario sobre Deuteronómio 28:24

מטר ארצך אבק ועפר [GOD SHALL MAKE] THE RAIN OF THY LAND POWDER AND DUST, through “a wind that comes after the rain” as the Talmud says (Taanit 3b); rain will fall but not as much as is needed, so that there will not be sufficient of it to lay the dust; the wind will come and blow the dust about and cover the leaves of the vegetation which are still wet from the water and it will adhere to them and so become mud which will afterwards become dry, and they will rot (Taanit 3b).

מטר ארצך, an expression describing anything descending from the sky, as in Genesis 19,24 when Sodom and Gomorrha were showered with sulfur and fire. Psalms 11,6 also uses the word מטר in that sense.

When the wind follows a rainfall, etc. This is the expression of the Gemora. Rashi is answering: How can it say that rain will turn into dust and soil which are two opposites, and to have two opposites in one situation is impossible! Therefore he explains, “When the wind follows, etc.”