On Taanis daf vav amud beis, do you understand the second pshat in Rashi...?
d'Lo Asa Mitra mei'Ikara. Tava l'Shasa d'Teves Minavlasa. Lashon Acher, Ha d'Asa Mitra mei'Ikara Tava d'Minavlasa.
How does it answer the Gemara's question?
yishai, beitar illit
The S'fas Emes too, is troubled by Rashi's second explanation.
He therefore suggests another explanation in the Gemara's answer, which he says, Rashi may have had in mind (though He himself queries it from the Lashon of the Gemara).
He suggests that what the Gemara means is if the ground is muddy from the excessive rain of Mar-Cheshvan, it is good, but not if it is Muddy from the rain of Teives.
Be'Virchas Kol Tuv,