Point queries · CSSL Docs

Point queries return exact values from the model’s native grid, with no reprojection or averaging. Weather Intelligence uses them for soundings, hodographs and forecast graphs.

Grid coordinates, not latitude and longitude

Points are addressed by row and col on the model’s native grid. There’s no public endpoint that returns the grid’s projection parameters yet, so converting a latitude and longitude to a row and column means working it out from the model’s own grid definition. These endpoints are mostly used by Weather Intelligence.

One point

GET/models/{model}/point

Returns one or more fields at one grid cell and one time step.

runstringqueryrequired

Run stamp from /runs.

hourintegerqueryrequired

Index into the model’s forecast_hour_axis.

row, colintegerqueryrequired

Grid cell, as zero-based indices into the native grid. /models/coverage gives the grid size as ny × nx.

fieldsstringqueryrequired

Comma-separated product names.

levelintegerquery

For pressure-level products, return only this index into levels_hpa. Leave it out to get the whole vertical column.

curl -s --compressed \
  "https://cyclone.cssl.ca/models/rdps/point?run=20260924T120000Z&hour=6&row=500&col=500&fields=T2m,T_ISBL"

{
  "run": "20260924T120000Z",
  "hour": 6,
  "valid_time": "2026-09-24T18:00:00Z",
  "forecast_hours": 85,
  "row": 500,
  "col": 500,
  "fields": {
    "T2m": { "unit": "K", "value": 290.16 },
    "T_ISBL": {
      "unit": "K",
      "levels_hpa": [1015.0, 1000.0, 985.0, 970.0],
      "values": [292.55, 291.93, 291.24, 290.6]
    }
  },
  "wind_rotation": { "cos": 0.97613484, "sin": -0.21716534 }
}

Single-level fields return a value. Pressure-level fields return levels_hpa and a matching values array, which together make a sounding. The column above is truncated. Missing values are null.

Time series

GET/models/{model}/series

Returns every time step of a run at one grid cell.

runstringqueryrequired

Run stamp.

row, colintegerqueryrequired

Grid cell.

fieldsstringqueryrequired

Comma-separated product names.

levelintegerquery

Index into levels_hpa for pressure-level products.

from, todatetimequery

Only include valid times in this range (inclusive). Either bound can be left out.

curl -s --compressed \
  "https://cyclone.cssl.ca/models/rdps/series?run=20260924T120000Z&row=500&col=500&fields=T2m&from=2026-09-24T12:00:00Z&to=2026-09-24T14:00:00Z"

{
  "run": "20260924T120000Z",
  "row": 500,
  "col": 500,
  "forecast_hours": 85,
  "valid_from": "2026-09-24T12:00:00Z",
  "valid_to": "2026-09-28T00:00:00Z",
  "wind_rotation": { "cos": 0.97613484, "sin": -0.21716534 },
  "fields": {
    "T2m": {
      "unit": "K",
      "levels_hpa": null,
      "series": [
        { "hour": 0, "valid_time": "2026-09-24T12:00:00Z", "value": 284.22998 },
        { "hour": 1, "valid_time": "2026-09-24T13:00:00Z", "value": 284.01 },
        { "hour": 2, "valid_time": "2026-09-24T14:00:00Z", "value": 284.32 }
      ]
    }
  }
}

valid_from and valid_to span the whole run, even when from and to narrow the series.

Grid-relative winds

Some models, including HRDPS and RDPS, publish wind components relative to their own grid axes rather than to true north. Both endpoints return wind_rotation for the requested cell. To get earth-relative components:

u_true =  cos × u + sin × v
v_true = -sin × u + cos × v

The rotation depends only on the cell’s position, so the same factors apply at every pressure level.