Soil moisture forecast

Product overview¶

Soil moisture forecast products extend existing Spire soil moisture products into the future using the Spire Operational Forecast (SOF-D) weather model. Global forecasts extend to approximately 15 days. Due to local-time matching (soil moisture products are valid at local noon), the effective forecast horizon is approximately 13–14 days depending on the region’s time zone offset from UTC. Forecast products retain the same quality flags as the underlying observation products.

D-MSSM-FC — Daily Medium-resolution Soil Moisture Forecast (6 km)¶

The D-MSSM-FC product provides a daily average of the forecast soil moisture field. API responses for forecast products include additional metadata:

{
  "data": [
    {
      "location": {
        "coordinates": {
          "lat": 14.0,
          "lon": 100.5
        }
      },
      "times": {
        "valid_time": "2026-02-17 12:00:00"
      },
      "values": {
        "d_mssm": 0.290,
        "pflag": 0.0,
        "qflag": 0.0,
        "data_source_am": 5.0,
        "data_source_pm": 5.0,
        "dai": 0.17,
        "lat": 14.0,
        "lon": 100.5,
        "aflag": 0,
        "issuance_time": "i20260216.t12z",
        "model": "sof-d",
        "update": "u1",
        "feed": "fc"
      }
    }
  ],
  "meta": {
    "message": null
  }
}

D-ESSM-FC — Daily Enhanced Soil Moisture Forecast (500 m)¶

D-ESSM-FC applies the same forecast methodology at 500 m resolution. API responses share the same structure as D-MSSM-FC, with d_essm as the value field.

D-HSSM-FC — Daily High-resolution Soil Moisture Forecast (100 m)¶

D-HSSM-FC applies the same forecast methodology at 100 m resolution. API responses share the same structure as D-MSSM-FC, with d_hssm as the value field.

Forecast file naming¶

Forecast netCDF4 files include the issuance time and model information in the filename:

smi.YYYYMMDD.tHHz.<resolution>.d-mssm-fc.<region>.iYYYYMMDD.tHHz.sof-d.u1.vMAmi.nc

Where:

• YYYYMMDD.tHHz (first) — valid date and time of the forecast

• iYYYYMMDD.tHHz — issuance date and time (when the forecast was produced)

• sof-d — driving weather model

• u1 — update cycle

Example: smi.20260220.t12z.6000m.d-mssm-fc.global.i20260216.t12z.sof-d.u1.v0201.nc