---
title: "Get a range of historical signal data"
method: GET
path: "/v3/historical"
tags: ["GET Historical"]
---

# Get a range of historical signal data

`GET /v3/historical`

Returns signal data (e.g. CO₂ MOER in lbs/MWh) for the specified `region`, `signal_type`, and time period. Values
are published in near real-time, periodically (e.g. at 5-minute frequency), and each value is valid starting from
its `point_time` for the duration described in `data_point_period_seconds`. The publishing delay (the difference
between the `point_time` for the value and the time that value is available in the API) varies by grid region. In
some regions the data will be available within one minute after a certain `point_time`, in other regions there may
be a delay of up to a few hours. Each query is limited to 32 days of data. Individual data point values may be
updated at any time after publishing (e.g. if better source data is obtained).

## Query parameters

- `start` string, date-time, required — (inclusive) ISO8601-compliant timezone-aware date string indicating earliest desired data, _used to select the first `point_time` included in the response_
- `end` string, date-time, required — (inclusive) ISO8601-compliant timezone-aware date string indicating latest desired data, _used to select the last `point_time` included in the response_
- `region` string, required — Region abbreviation associated with location, from result of query to `/v3/region-from-loc`
- `signal_type` union, required — Use to select any available `signal_type` which is authorized for your account
  - 'co2_moer' | 'health_damage'
  - 'co2_aoer'
- `model` string, date, nullable — Use to return different models from defaults.
- `include_imputed_marker` boolean — Use to return whether or not the value associated with a `point_time` is generated with imputed data.
- `updated_since` string, date-time, nullable — Filter results for data newer than the provided datetime.

## Response `200`

Successful Response

- V3Response
  - `data` APIV3DataResponseFormat[], required
    - `point_time` string, date-time, required
    - `value` number, required
    - `last_updated` string, date-time, nullable
    - `imputed_data_used` boolean, nullable
  - `meta` V3Metadata, required
    - `data_point_period_seconds` integer, required
    - `region` string, required
    - `signal_type` union, required
      - 'co2_moer' | 'health_damage'
      - 'co2_aoer'
    - `units` string, required
    - `warnings` WarningType[], required
      - `type` string, required
      - `message` string, required
    - `model` V3ModelMetadata
      - `date` string, date, required
      - `type` 'interchange' | 'average' | 'binned_regression' | 'heatrate' | 'proxy' | 'synthetic_proxy' | 'forecast'

## Other responses

- `400` — Bad Request
- `403` — Forbidden
- `422` — Unprocessable Entity

---

[API](https://skmtc.dev/watttime/apis/watttime-data-api.md) · [All operations](https://skmtc.dev/watttime/apis/watttime-data-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/watttime/watttime-data-api/revisions/2c85341b2839/schema)