What is the method for fasting in expiation for unintentional killing? Are the two months to be reckoned by the Hijri or Gregorian calendar? Is it sufficient to fast for 60 consecutive days regardless of the beginning of the month? Is it permissible to delay the fasting until winter due to a health condition?

Expiation, of all types, is reckoned by lunar months, regardless of their length or shortness, and has no relation to solar months. It is permissible to begin it at any point in the month. If one does not begin at the beginning of the lunar month, then what was missed from the first month is completed from the third month. There is no objection to delaying fasting until the winter months for those for whom fasting in summer is difficult.