Charak Samhita
चितः शीते कफश्चैवं वसन्ते समुदीर्यते। वर्षास्वम्लविपाकाभिरद्भिरोषधिभिस्तथा ॥४३॥
Pitta gets aggravated during autumn season because of its inherent hot properties and hot environment. Kapha gets accumulated in winters and gets aggravated during spring season.
english translation
citaH zIte kaphazcaivaM vasante samudIryate। varSAsvamlavipAkAbhiradbhiroSadhibhistathA ॥43॥
hk transliteration by Sanscript