The Prophet (صلى ألله عليه وسلم) said: “Fasting in winter is an easily acquired booty.” (Reported by Aḥmad, al-Bayhaqī, al-Tabarānī, Ibn ‘Adī, Ibn ʿAsākir and others, and Shaykh al-Albānī graded it authentic.) 

Since the winter days are shorter and cooler than the other days of the year, a Muslim can fast the winter days easily.

Ibn Rajab (رحمه الله) stated: “Indeed, the believer is able to fast the days of winter without difficulty or being troubled by hunger and thirst because its days of fasting are short and cold, so the difficulty of fasting is unnoticeable.” (Laṭāʾif al-Maʿārif, pg. 326)

Abū Hurayrah (رضي الله عنه) would say: “Shall I not direct you to an easily acquired booty?” They said: “Certainly”; so he said: “Fasting in the winter is an easily acquired booty.” (Laṭāʾif al-Maʿārif, pg. 326)

Therefore, we should strive to attain the easy reward of fasting in winter.