Get precipitation forecast

Use this action to retrieve the precipitation forecast series for one of your Environment Canada locations: a short-interval series covering the recent past and the next hour or so, and an hourly series covering up to the next two days. The result is intended for building your own precipitation chart, for example with a template sensor or a custom card.

This action returns its result in a response variable, which you can use in later steps of the same automation or script.

Using this action from the user interface

If you prefer building automations and scripts visually, Home Assistant walks you through this action step by step. You pick what to target, tweak a few options, and save. No YAML knowledge required.

To get the precipitation forecast from an automation or a script:

1. Go to Settings > Automations & scenes.
2. Open an existing automation or script, or select Create automation > Create new automation.
3. If you’re setting up a new automation, add a trigger in the When section. Scripts don’t need a trigger. They run when something else calls them.
4. In the Then do section, select Add action.
5. From the search box, search for and select Environment Canada: Get precipitation forecast.
6. Select the Environment Canada service to get the precipitation forecast for, and set any of the options you need.
7. In the Response variable field, enter a name to store the data in, such as precipitation.
8. Select Save.

This action does not support targets. In the UI, you are not prompted to choose an area, device, entity, or label.

Options in the UI

Using this action in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this action as environment_canada.get_precipitation_forecast. Store the result in a response variable so you can use it in later steps:

action: environment_canada.get_precipitation_forecast
data:
  config_entry_id: YOUR_CONFIG_ENTRY_ID
response_variable: precipitation

This stores the precipitation forecast series for the selected location in precipitation.

Options in YAML

Response data

The response has three keys:

• nowcast: A short-interval precipitation rate series, combining recent observed radar with roughly the next hour of radar extrapolation.
• hourly: An hourly precipitation amount, probability, and type series, covering up to the next two days.
• metadata: Attribution and reference information for the series, such as the timestamp of the most recent radar observation.

Each nowcast entry has a timestamp field along with fields such as rate, unit, precip_type, and forecast, which is true for an extrapolated entry and false for an observed one. Each hourly entry has a timestamp field along with fields such as amount, probability, conditional_amount, expected_amount, and precip_type.

nowcast:
  - timestamp: "2024-01-01T12:00:00+00:00"
    rate: 1.2391
    unit: mm/h
    precip_type: rain
    forecast: false
hourly:
  - timestamp: "2024-01-01T13:00:00+00:00"
    amount: 1.726
    probability: 57
    conditional_amount: 0.909
    expected_amount: 0.518
    precip_type: Rain
metadata:
  attribution: Data provided by Environment Canada
  timestamp: "2024-01-01T12:00:00+00:00"

Good to know

• Unlike the weather and radar camera entities in this integration, this action is not backed by a coordinator: each call queries Environment Canada directly, so the response reflects the latest available radar and model data at the time of the call.
• Repeated calls with the same location and options within a few minutes can reuse a very recent result instead of triggering a new query.

Try it yourself

Ready to test this? Open Settings > Tools > Actions, search for this action, fill in the fields, and select Perform action. You see what happens on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] without writing a line of YAML.

More examples

Real scenarios where this action shows up in automations and scripts. Copy any example and adapt it to your setup.

Automation: notify about rain in the next hour

This automation checks the short-interval series every 10 minutes and, if any of the next hour’s rates are above zero, notifies you with the upcoming rates so you know rain is about to start without checking the app.

• Trigger: Time pattern (every 10 minutes)
• Action: Get precipitation forecast
  • Precipitation type: Rain
  • Past minutes: 0
  • Future minutes: 60
• Condition: Template
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Notify about rain in the next hour"
triggers:
  - trigger: time_pattern
    minutes: "/10"
actions:
  - action: environment_canada.get_precipitation_forecast
    data:
      config_entry_id: YOUR_CONFIG_ENTRY_ID
      precip_type: rain
      past_minutes: 0
      future_minutes: 60
    response_variable: precipitation
  - condition: template
    value_template: >
      {{ precipitation.nowcast | selectattr('rate', 'gt', 0) | list
      | count > 0 }}
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: >
        Rain expected in the next hour: {{ precipitation.nowcast
        | map(attribute='rate') | list }}

Automation: notify about precipitation in the next 24 hours

This automation runs every evening, retrieves the hourly series, and notifies you with the total expected amount, so you can plan for the next day.

• Trigger: Time (21:00)
• Action: Get precipitation forecast
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Notify about precipitation in the next 24 hours"
triggers:
  - trigger: time
    at: "21:00:00"
actions:
  - action: environment_canada.get_precipitation_forecast
    data:
      config_entry_id: YOUR_CONFIG_ENTRY_ID
    response_variable: precipitation
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: >
        Expected precipitation over the next 24 hours: {{
        precipitation.hourly | sum(attribute='expected_amount')
        | round(1) }} mm.

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the action you’re calling and what you expected to happen, or share on our subreddit /r/homeassistant.

Related actions

Explore related actions:

• Get alerts: Retrieves the active weather alerts for an Environment Canada location.

• Get forecasts: Retrieves the raw daily and hourly forecast data from Environment Canada.

• Set radar type: Sets the type of radar imagery shown by an Environment Canada radar camera.