Tree rings, with annual resolution and precise dating, can provide temporally high-resolution proxy records of past climate. However, annually-resolved tree ring data still restrict how tree-ring-based paleoclimate reconstructions can be used in subsequent applications, where finer resolutions are desirable. For example, it is often difficult to compare annual climate reconstructions against historical events, because an event may have happened outside the target season of the reconstruction, or two opposite events (a flood and a drought) may be smoothed out by a reconstruction that targets the annual average (Wise, 2021). In addition, and specific to water resources, annual streamflow reconstructions have provided important insights into surface water availability, but cannot be used directly in water management models which require monthly, weekly, or even daily data (Galelli et al., 2021).How do we obtain subannual climate reconstructions from annual tree rings? Earliest attempts used statistical methods to disaggregate each annual value to multiple subannual ones, assuming a fixed relationship between the two resolutions (