In-Depth Expanding

A synchronous endpoint used to calculate weather and NatCat risk for an expanding window of event dates. This endpoint is designed for cumulative perils (e.g. cumulative rainfall) where you want to see how probabilities evolve as the observation window grows.

Request

POST /v1/in-depth/expanding

Headers

Body

Event object

Same as the Daily endpoint.

Response

Success (200) or Multi-Status (207)

200 means all requested work succeeded. 207 means one or more event/window/peril items failed and details are available in failed_items; successful results are still returned normally in results.

Result object

The metadata and failed_items objects are the same as the Daily endpoint. For expanding responses, each peril_outcomes item is a unique event-window-peril combination. For expanding failures, window_index is set when a specific window failed.

The number of result objects is the number of days (from your start date and end date inclusively) + window days.

Example

Example request

curl -X 'POST' \
  'https://prod-external-weather-api.birdseyeviewtechnologies.com/v1/in-depth/expanding' \
  -H 'accept: application/json' \
  -H 'X-API-Key: YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
  "perils": ["CumulativeRain"],
  "events": [
    {
      "index": 0,
      "location": "Manchester UK",
      "start_date": "2025-07-10",
      "end_date": "2025-07-10"
    }
  ],
  "window_days": 1
}'

Example response

{
  "results": [
    {
      "index": 0,
      "window_index": 0,
      "peril": "CumulativeRain",
      "latitude": 53.4808,
      "longitude": -2.2426,
      "threshold": [0, 5, 10, 15, 20, 25, 30],
      "probability": [0.99, 0.85, 0.60, 0.35, 0.18, 0.08, 0.03],
      "unit": "mm"
    },
    {
      "index": 0,
      "window_index": 1,
      "peril": "CumulativeRain",
      "latitude": 53.4808,
      "longitude": -2.2426,
      "threshold": [0, 5, 10, 15, 20, 25, 30, 35, 40],
      "probability": [0.99, 0.90, 0.72, 0.50, 0.30, 0.16, 0.08, 0.03, 0.01],
      "unit": "mm"
    }
  ],
  "failed_items": [],
  "metadata": {
    "total_requested": 1,
    "successful": 1,
    "failed": 0,
    "event_outcomes": {
      "requested": 1,
      "successful": 1,
      "partially_successful": 0,
      "failed": 0
    },
    "peril_outcomes": {
      "requested": 2,
      "successful": 2,
      "failed": 0
    }
  }
}

This request has one event day and one additional window day, producing two event-window-peril outcomes.

How the expanding window works

Given start_date, end_date, and window_days:

1. The window always starts at start_date - window_days.
2. The first iteration (window_index=0) covers from the window start up to window start + 1 day.
3. Each subsequent iteration expands the end by one day, until end_date is reached.

This allows you to see how cumulative probabilities change as the observation period grows.

Limits

• Maximum 10 peril-event combinations per request.
• window_days must be between 0 and 7 (inclusive).
• Only cumulative perils are accepted. See Expanding perils for list of available expanding perils

Errors