Forecast scorecard — Korea
We re-score our own weather forecasts against what actually happened next, every day. We don't cherry-pick the flattering numbers: sample sizes, the date the record starts, and days that are still awaiting evaluation are all shown as they are.
Market: US · Korea · Japan · Hong Kong · Crypto
Not enough forecast days have completed 21 trading days yet, so we can't compare. Sample still too small
Whole period
Baseline: across all days regardless of the forecast, the average return 21 trading days later was +8.52% (11 scored days).
| Weather | Forecast days | Avg after 5 days | Avg after 21 days | Share up (21d) | Awaiting | vs baseline |
|---|---|---|---|---|---|---|
| Sunny | 3 | -0.54% | – | – | 3 | – |
| Cloudy | 22 | +1.36% | +5.19% | 100% | 15 | -3.32%p |
| Rain | 7 | +5.08% | +14.33% | 100% | 3 | +5.82%p |
| Storm | 0 | – | – | – | 0 | – |
| All | 32 | +1.97% | +8.52% | 100% | 21 | – |
Month by month
| Month | Weather | Forecast days | Avg after 5 days | Avg after 21 days | Share up (21d) | Awaiting |
|---|---|---|---|---|---|---|
| 2026-09 | Sunny | 1 | +1.74% | – | – | 1 |
| 2026-09 | Cloudy | 4 | – | – | – | 4 |
| 2026-09 | Rain | 1 | – | – | – | 1 |
| 2026-08 | Sunny | 2 | -1.67% | – | – | 2 |
| 2026-08 | Cloudy | 16 | +1.93% | +6.38% | 100% | 11 |
| 2026-08 | Rain | 2 | +1.61% | – | – | 2 |
| 2026-07 | Cloudy | 2 | -3.26% | +2.21% | 100% | 0 |
| 2026-07 | Rain | 4 | +6.82% | +14.33% | 100% | 0 |
If you had followed the weather
Following the weather: -8.24% cumulative, max drawdown -11.10% Sample still too small
Just holding: +2.94% cumulative, max drawdown -17.20%
Limits
- The record only starts in July 2026, so the sample is very small. Any cell with fewer than 30 cases could easily be chance.
- Only index returns are measured. Real fills, taxes and FX are not included, and the 'followed the weather' cost is an assumed 0.1% per switch.
- The forecast rules have changed a few times (see the rule change history). Past results do not guarantee future ones.