The ledger, through October 1
Mean absolute temperature error runs 2.23°F at day 1 and 3.93°F at day 7, over 515,212 settled forecast-observation pairs.
The LedgerThursday, October 1, 2026The Ledger
JSON
Milepost 1256
Every forecast this network publishes for a station with an ASOS report is compared against that report once the valid time has passed, and the residual is written down. This is the standing table for September 1–October 1, 2026.
| Lead | NDFD | NBM | pairs |
|---|---|---|---|
| Day 1 | 2.30 | 2.23 | 70,389 |
| Day 2 | 2.52 | 2.45 | 70,401 |
| Day 3 | 2.79 | 2.67 | 70,241 |
| Day 4 | 3.04 | 2.92 | 70,371 |
| Day 5 | 3.38 | 3.24 | 70,381 |
| Day 6 | 3.73 | 3.60 | 70,471 |
| Day 7 | 4.09 | 3.93 | 57,496 |
| Day 8 | — | 4.21 | 35,462 |
Mean absolute error, °F, temperature. ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.
The numbers in this piece, with what they are measured against
| day-1 mean absolute temperature error, NBM Forecast Network verification ledger |
2.23 °F | of 34,891 September 1–October 1, 2026 |
| day-3 mean absolute temperature error, NBM Forecast Network verification ledger |
2.67 °F | of 34,741 September 1–October 1, 2026 |
| day-5 mean absolute temperature error, NBM Forecast Network verification ledger |
3.24 °F | of 34,881 September 1–October 1, 2026 |
| day-7 mean absolute temperature error, NBM Forecast Network verification ledger |
3.93 °F | of 35,425 September 1–October 1, 2026 |
| day-1 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.3 °F | of 35,498 September 1–October 1, 2026 |
| day-3 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.79 °F | of 35,500 September 1–October 1, 2026 |
| day-5 mean absolute temperature error, NDFD Forecast Network verification ledger |
3.38 °F | of 35,500 September 1–October 1, 2026 |
| day-7 mean absolute temperature error, NDFD Forecast Network verification ledger |
4.09 °F | of 22,071 September 1–October 1, 2026 |
- Milepost
- 1256 · laid 2026-10-01T00:25:12Z
- Desk
- ledger v1
- Method
- ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.
- Stores
- /home/maue/forecastpoints/data/verify/2026-09.ndjson
- Tagged
- I-500 Daily Weather · by rule, at build
- Digest
- 254a03a8dcde9cabe505b82cf956aa937d419326e9ecd4fcdbdacc22f30a105b