diff --git a/homeassistant/components/forecast_solar/__init__.py b/homeassistant/components/forecast_solar/__init__.py
index b00e5f1c4ce..b20a0befb96 100644
--- a/homeassistant/components/forecast_solar/__init__.py
+++ b/homeassistant/components/forecast_solar/__init__.py
@@ -5,10 +5,12 @@ from datetime import timedelta
 import logging
 
 from forecast_solar import ForecastSolar
+import voluptuous as vol
 
+from homeassistant.components import websocket_api
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import CONF_API_KEY, CONF_LATITUDE, CONF_LONGITUDE
-from homeassistant.core import HomeAssistant
+from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator
 
 from .const import (
@@ -55,7 +57,9 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     )
     await coordinator.async_config_entry_first_refresh()
 
-    hass.data.setdefault(DOMAIN, {})
+    if DOMAIN not in hass.data:
+        hass.data[DOMAIN] = {}
+        websocket_api.async_register_command(hass, ws_list_forecasts)
     hass.data[DOMAIN][entry.entry_id] = coordinator
 
     hass.config_entries.async_setup_platforms(entry, PLATFORMS)
@@ -77,3 +81,20 @@ async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 async def async_update_options(hass: HomeAssistant, entry: ConfigEntry) -> None:
     """Update options."""
     await hass.config_entries.async_reload(entry.entry_id)
+
+
+@websocket_api.websocket_command({vol.Required("type"): "forecast_solar/forecasts"})
+@callback
+def ws_list_forecasts(
+    hass: HomeAssistant, connection: websocket_api.ActiveConnection, msg: dict
+) -> None:
+    """Return a list of available forecasts."""
+    forecasts = {}
+
+    for config_entry_id, coordinator in hass.data[DOMAIN].items():
+        forecasts[config_entry_id] = {
+            timestamp.isoformat(): val
+            for timestamp, val in coordinator.data.watts.items()
+        }
+
+    connection.send_result(msg["id"], forecasts)
diff --git a/tests/components/forecast_solar/test_init.py b/tests/components/forecast_solar/test_init.py
index 719041aaf58..7544f7d352b 100644
--- a/tests/components/forecast_solar/test_init.py
+++ b/tests/components/forecast_solar/test_init.py
@@ -1,4 +1,5 @@
 """Tests for the Forecast.Solar integration."""
+from datetime import datetime, timezone
 from unittest.mock import MagicMock, patch
 
 from forecast_solar import ForecastSolarConnectionError
@@ -14,14 +15,37 @@ async def test_load_unload_config_entry(
     hass: HomeAssistant,
     mock_config_entry: MockConfigEntry,
     mock_forecast_solar: MagicMock,
+    hass_ws_client,
 ) -> None:
     """Test the Forecast.Solar configuration entry loading/unloading."""
+    mock_forecast_solar.estimate.return_value.watts = {
+        datetime(2021, 6, 27, 13, 0, tzinfo=timezone.utc): 12,
+        datetime(2021, 6, 27, 14, 0, tzinfo=timezone.utc): 8,
+    }
+
     mock_config_entry.add_to_hass(hass)
     await hass.config_entries.async_setup(mock_config_entry.entry_id)
     await hass.async_block_till_done()
 
     assert mock_config_entry.state == ConfigEntryState.LOADED
 
+    # Test WS API set up
+    client = await hass_ws_client(hass)
+    await client.send_json(
+        {
+            "id": 5,
+            "type": "forecast_solar/forecasts",
+        }
+    )
+    result = await client.receive_json()
+    assert result["success"]
+    assert result["result"] == {
+        mock_config_entry.entry_id: {
+            "2021-06-27T13:00:00+00:00": 12,
+            "2021-06-27T14:00:00+00:00": 8,
+        }
+    }
+
     await hass.config_entries.async_unload(mock_config_entry.entry_id)
     await hass.async_block_till_done()