Digital calendars and other technologies for social event planning leave little space to communicate uncertainty regarding time, place or the ability to attend an event. However, narratives of certainty can be detrimental and lead to the marginalisation of those who find it hard to cope with rigid and strictly paced schedules, such as people with health conditions or caring responsibilities. In this paper, we explore uncertainty as the starting point and leading principle behind digital scheduling tools. We present Haze, a speculative tool and user interface, designed to gain insights on participants’ perceptions of uncertainty-based scheduling scenarios. We report on two qualitative studies (total of 21 participants), which indicate that a change in perspective towards uncertainty can challenge moral assumptions around certainty, increase temporal empathy, and indeed support those who are particularly affected by uncertainty. These findings help shift and expand the repertoire of temporality and discuss moral and social responsibilities for design and HCI.