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Sundial (Base 128M)

Model directory
thuml/sundial-base-128m

128M params | Upstream checkpoint

Sundial is THUML's native generative TSFM for continuous-valued forecasting. The official card presents it as a 128M-parameter model built to generate multiple plausible futures rather than a single trajectory, making it one of the most directly probabilistic models in the model landscape and a strong option when distribution quality matters as much as point accuracy.

Architecturally it is a causal decoder-only transformer trained with a TimeFlow / flow-matching loss, which lets it model continuous values natively instead of relying on the discrete tokenization used by many other forecasting families. It is pretrained on TimeBench, a corpus of 1032B time points, with the model card listing THUML's UTSD, LOTSA, and the Chronos datasets as core upstream sources.

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  • Community forecasting playground

    hosted demo · Source checked 2026-10-06

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Hugging Face provider mappings checked 2026-10-06. No Inference Provider mapping was listed for this checkpoint.

Model Classification

Family

Sundial

Type

time series foundation model

Pretrained time-series model for zero-shot or few-shot forecasting workloads.

Training Data

TimeBench / 1032B time points, with the model card listing THUML UTSD, LOTSA, and Chronos datasets as core upstream sources.

Recommended For

  • • Probabilistic forecasting where distribution quality matters
  • • Teams that want native continuous generative forecasting rather than tokenization

Strengths

  • • Designed around probabilistic future generation
  • • Native continuous-valued modeling rather than discrete token bins

Limitations

  • • Less suited to broad non-forecasting tasks
  • • Generative probabilistic focus can be overkill for simple point-forecast-only use cases

Capabilities

forecastingprobabilistic-forecastingquantile-forecastingzero-shot

Tags

sundialgenerativeprobabilisticthuml

Specifications

Parameters
128M
Architecture
causal decoder-only transformer with TimeFlow loss / flow matching
Context length
n/a
Max context
n/a
Minimum history
n/a
Recommended history
n/a
Input step
n/a
Required target series
1
Temperature
Ignored
Top P
Ignored
Max output
n/a
License
n/a