BuienAlarm Integration for Home Assistant

A Home Assistant integration that uses the BuienAlarm API to provide rain forecast data for any location in the Netherlands.

Disclaimer. This is an unofficial community integration. It is not affiliated with or endorsed by BuienAlarm. The brand icons shipped in custom_components/buienalarm/brand/ are generic rain-cloud graphics, not the BuienAlarm trademark.

Features

• Next shower sensor with a human-readable status (Dutch or English)
• Next shower start sensor with device_class: timestamp
• Current shower end sensor with device_class: timestamp
• Rain-intensity threshold sensors (level_light, level_moderate, level_heavy) with unit mm/h
• Configurable through the Home Assistant UI (config flow + options flow)
• Diagnostics support — download a JSON dump of the integration state for troubleshooting, with latitude/longitude redacted automatically
• Multilingual UI — see Translations below for the full list of supported languages and how to contribute
• Companion Lovelace card available as a separate HACS install — see Dashboard card below

For the Dutch version of this README, see installation.md.

Requirements

• Home Assistant 2024.12 or newer

Installation

Method 1 — HACS (recommended)

1. Make sure HACS is installed.
2. In HACS, open the menu (top right) → Custom repositories.
3. Add https://github.com/lancer73/ha-buienalarm with category Integration.
4. Search for BuienAlarm in the HACS store and install it.
5. Restart Home Assistant.

Method 2 — Manual

1. Copy the custom_components/buienalarm/ directory from this repository into your Home Assistant config/custom_components/ directory.
2. Restart Home Assistant.

Configuration

After installation:

1. Go to Settings → Devices & services → Add integration.
2. Search for BuienAlarm and select it.
3. Provide:
   • Latitude and Longitude of the location to forecast for
   • Scan interval — how often to refresh data (3–60 minutes, default 5)
   • Language — Dutch or English

The integration validates the API call before creating the entry, so an invalid location or a connectivity problem is reported immediately.

The scan interval and language can be changed afterwards via the integration card's Configure button. Changes are applied immediately without an HA restart.

Entities

A single device is created per configured location, exposing six sensors:

Sensor (English UI)	Sensor (Dutch UI)	Type	Description
Next shower	Volgende bui	text	Human-readable status, e.g. "14:25 (in 30 minutes)"
Next shower start	Start volgende bui	timestamp	When the next shower starts; unknown if none in window
Current shower end	Einde huidige bui	timestamp	When the ongoing/upcoming shower ends; unknown if none in window
Light threshold	Drempel licht	mm/h	Light-rain threshold reported by the API
Moderate threshold	Drempel gemiddeld	mm/h	Moderate-rain threshold
Heavy threshold	Drempel zwaar	mm/h	Heavy-rain threshold

The next-shower sensor exposes these state attributes:

• next_rain_forecast — same value as the state, for templating
• rain_forecast — list of {precip: mm/h, attime: unix_ts} entries covering the full forecast window
• period_type — wet (next shower coming), dry (current shower will end), or nan (no transition in window)
• period_start — clock time string (HH:MM) of the upcoming transition

The raw_data attribute that earlier versions exposed has been removed in 1.0.0. The full upstream payload is now available through the Download diagnostics button on the integration card.

Finding your entity IDs

Entity IDs are derived from the device name and your locale, so the exact ID depends on which language you picked. Examples:

• English: sensor.buienalarm_next_shower, sensor.buienalarm_next_shower_start, sensor.buienalarm_current_shower_end, sensor.buienalarm_light_threshold, sensor.buienalarm_moderate_threshold, sensor.buienalarm_heavy_threshold
• Dutch: sensor.buienalarm_volgende_bui, sensor.buienalarm_start_volgende_bui, sensor.buienalarm_einde_huidige_bui, sensor.buienalarm_drempel_licht, sensor.buienalarm_drempel_gemiddeld, sensor.buienalarm_drempel_zwaar

Open Settings → Devices & services → BuienAlarm and click your device to see the entity IDs that were actually created on your install. The YAML examples below assume the English IDs — adjust them for your install.

Example automation

automation:
  - alias: "Rain warning"
    trigger:
      - platform: state
        entity_id: sensor.buienalarm_next_shower_start
    condition:
      - condition: template
        value_template: "{{ trigger.to_state.state not in ['unknown', 'unavailable'] }}"
    action:
      - service: notify.mobile_app
        data:
          title: "Rain incoming"
          message: >
            Next shower starts at
            {{ as_timestamp(states('sensor.buienalarm_next_shower_start'))
               | timestamp_custom('%H:%M') }}.

The previous "trigger on every state change of the status sensor" pattern still works, but the timestamp sensor is the cleaner trigger because it only fires when an actual transition is detected and never on every text-format update.

Dashboard card

A companion Lovelace card is available as a separate HACS install: lovelace-buienalarm-card. It pairs with this integration and reads its sensors directly — no templating or data_generator needed.

Install it via HACS (Custom repositories → category Dashboard), then add the card from the Lovelace card picker. Minimal YAML:

type: custom:buienalarm-card
next_shower_sensor: sensor.buienalarm_next_shower
light: sensor.buienalarm_light_threshold
moderate: sensor.buienalarm_moderate_threshold
heavy: sensor.buienalarm_heavy_threshold

Full configuration options, screenshots, and YAML examples are in the card's README.

Without the companion card

If you'd rather not install another HACS package, the integration's sensors work with any standard Lovelace card. A simple entities card:

type: entities
title: Rain forecast
entities:
  - entity: sensor.buienalarm_next_shower
  - entity: sensor.buienalarm_next_shower_start
  - entity: sensor.buienalarm_current_shower_end

For a chart, the apexcharts-card community card works well too: configure all series against the next-shower sensor, drive the time axis from its rain_forecast attribute, and read each threshold value with hass.states['sensor.buienalarm_light_threshold'].state (and similarly for moderate/heavy) inside the series' data_generator. The companion card above does this and more, with a visual editor — recommended unless you specifically want the apexcharts-card look.

Privacy and security

• All API calls are HTTPS with default certificate verification.
• No credentials are required, transmitted, or stored.
• Latitude and longitude are redacted from the diagnostics download.
• The config-entry unique_id and entry title are based on coordinates rounded to ~110 m and ~1.1 km respectively, so a registry export does not pinpoint your home address.
• Existing entries from earlier versions are migrated to the rounded unique_id format automatically on first load.

Translations

The integration supports the following languages for state text (the human-readable status of the next-shower sensor, e.g. "in 30 minutes" / "over 30 minuten") and for the Home Assistant UI (entity names, config-flow labels):

nl (Dutch), en (English), fr (French), es (Spanish), pt (Portuguese, Portugal), pt-BR (Portuguese, Brazil), fy (West Frisian / Frysk), tr (Turkish), ar (Arabic, Modern Standard), de (German), de-CH (Swiss German).

The state-text language follows the language config option chosen by the user. The HA UI labels follow the user's HA UI locale, with a fallback chain: exact match → base language (e.g. pt-PT → pt, de-AT → de) → English.

Help wanted: native-speaker review

The translations for every language other than Dutch and English were produced as machine-quality starting points and have not yet been reviewed by native speakers. They are functional, but a native speaker will inevitably notice clumsy phrasing or better word choices.

If you are a native speaker of any of these languages, contributions are warmly welcomed, no matter how small:

• Strings to review live in two places: custom_components/buienalarm/const.py (the LANGUAGE_STRINGS dict — five state-text strings per language), and custom_components/buienalarm/translations/<locale>.json (the HA UI translations — about a dozen strings).
• Open a pull request with your suggested edits, or open an issue if you'd rather discuss specific phrasing first. Reviews of just one or two strings are valuable too — please don't feel you have to fix every string at once.
• If your language isn't on the list and you'd like to add it, both files take new entries cleanly; an issue or PR to start the conversation is welcome.

Notes on what isn't included

• de-AT (Austrian German) is not a separate locale. Standard German is used; the few Austria-specific words don't appear in any of these strings. HA UIs configured to de-AT fall through to de.
• Moroccan Darija is not included. Morocco's written language is Modern Standard Arabic, which is available as ar. Spoken Darija has no commonly-used locale code and no HA support.

Upgrading from 0.1.x

Upgrade in place via HACS. On first restart the integration will:

1. Migrate the legacy buienalarm_next_rain_<lat>_<lon> sensor to the new ID scheme — your history is preserved.
2. Round the entry's unique_id so coordinates aren't exposed in registry exports.
3. Bump the entry version from 1 to 2.

If your dashboards reference the raw_data attribute (e.g. an older apexcharts-card example reading attributes.raw_data.levels.light), update them to read from the dedicated threshold sensors instead, or install the companion card which handles this for you. The status sensor's other attributes (rain_forecast, period_type, period_start, next_rain_forecast) are unchanged.

See CHANGES.md for the full changelog.

Troubleshooting

If the integration is not working as expected:

1. Open Settings → Devices & services → BuienAlarm → ⋮ → Download diagnostics and inspect the JSON. Latitude, longitude, and any other sensitive fields are redacted.
2. Enable debug logging via Settings → Devices & services → BuienAlarm → ⋮ → Enable debug logging, reproduce the issue, then disable debug logging — Home Assistant will offer the log file as a download.
3. Verify your internet connection and that the configured coordinates fall within the BuienAlarm coverage area (the Netherlands and immediately surrounding regions).
4. Check the Home Assistant log for messages from the buienalarm logger.

Related projects

• lovelace-buienalarm-card — Lovelace card that visualises this integration's sensors. HACS Dashboard category. Optional, but recommended.

License

This project is licensed under the MIT License — see the LICENSE file for details.

The BuienAlarm name and any official trademarks belong to their respective owners. This integration is an unofficial client of BuienAlarm's public forecast API.