Is cursing time considered disbelief?
Wa ‘alaykum assalam wa rahmatullah wa barakatuh.
I pray you are well.
Such comments are inappropriate because of the hadith quoted in the question. Although the comments are directed to the year specifically, and time in general, Allah is the one who decreed the matters that occur in that time. All of His actions are full of wisdom and benefit for us, so criticism of time is an indirect insult to Him.
This is something a believer should abstain from. If we are fair in our outlook – no matter how intense trials are – in every moment we have more blessings than difficulties.
Is Cursing Time Kufr?
No, cursing time is not kufr, but it is a sin that a believer sees as serious and should repent from. Scholars have stated that believing in time itself as the direct cause of calamities is considered shirk. However, the context of the statements above is not that. Rather, it is a criticism of time as a period in which such things occur. That is not kufr. [Nawawi, Sharh Sahih Muslim]
May Allah grant us excellent adab with Him.
[Shaykh] Abdul-Rahim Reasat
Checked and Approved by Shaykh Faraz Rabbani