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Harvora™ model-card brief

Frost risk forecasting for New Zealand orchards model card

This model card documents the method, evidence target and limitations for frost risk forecasting for new zealand orchards. This is a held-out regional weather benchmark, not yet commercial orchard-outcome validation. The alarm threshold is deliberately tuned to miss almost nothing, so about half of flagged nights are true frost events (positive predictive value ≈ 46.91%) — the trade-off is published, not hidden. Full detail (TP 76 / FN 8 / FP 86 / TN 2,186, rounded from committed four-decimal rates) is in the technical brief.

Direct answer

What this supports

Each block gets a probability distribution of overnight minima and freeze chance — so a frost probability reads directly against your protection decision for that night, rather than a single alarm number.

Intended for New Zealand growers, technical partners, lenders and insurers.

Evidence and method

How the signal is formed

Hourly ensemble forecasts are bias-corrected per block and sampled as a 1,000-draw Monte Carlo distribution of overnight minima and freeze probability.

Evidence grade: ESTIMATE

Weather-benchmark measured today; every grower outcome logged in the product feeds the field benchmark it is measured against next.

Boundary

How to read this evidence

This is a held-out regional weather benchmark, not yet commercial orchard-outcome validation. The alarm threshold is deliberately tuned to miss almost nothing, so about half of flagged nights are true frost events (positive predictive value ≈ 46.91%) — the trade-off is published, not hidden. Full detail (TP 76 / FN 8 / FP 86 / TN 2,186, rounded from committed four-decimal rates) is in the technical brief.

Provenance

Sources and related evidence

Published 25 August 2026 · Last reviewed 25 August 2026 · Harvora technical review

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