Add OpenWeatherMap weather forecasts. Closes #48

Show 8-day Bristol home weather on the index and weekends pages.
Show destination weather per day on the trip list and trip page.
Cache forecasts in ~/lib/data/weather/ and refresh via update.py.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web_view.py

@@ -31,6 +31,7 @@ import agenda.thespacedevs
 import agenda.trip
 import agenda.trip_schengen
 import agenda.utils
+import agenda.weather
 from agenda import ical, calendar, format_list_with_ampersand, travel, uk_tz
 from agenda.event import Event
 from agenda.types import StrDict, Trip
@@ -120,6 +121,7 @@ async def index() -> str:
         start_event_list=date.today() - timedelta(days=1),
         end_event_list=date.today() + timedelta(days=365 * 2),
         render_time=(time.time() - t0),
+        home_weather=get_home_weather(),
         **data,
     )
 
@@ -296,6 +298,15 @@ async def weekends() -> str:
     weekends = agenda.busy.weekends(
         start, busy_events, trip_list, app.config["PERSONAL_DATA"]
     )
+
+    home_weather = get_home_weather()
+    home_weather_by_date = {f["date"]: f for f in home_weather}
+    for weekend in weekends:
+        saturday = weekend["date"]
+        sunday = saturday + timedelta(days=1)
+        weekend["saturday_weather"] = home_weather_by_date.get(saturday.isoformat())
+        weekend["sunday_weather"] = home_weather_by_date.get(sunday.isoformat())
+
     return flask.render_template(
         "weekends.html",
         items=weekends,
@@ -583,6 +594,21 @@ def sum_distances_by_transport_type(trips: list[Trip]) -> list[tuple[str, float]
     return list(distances_by_transport_type.items())
 
 
+def get_home_weather() -> list[StrDict]:
+    """Get Bristol home weather forecast, with date objects added for templates."""
+    from datetime import date as date_type
+
+    forecasts = agenda.weather.get_forecast(
+        app.config["DATA_DIR"],
+        app.config.get("OPENWEATHERMAP_API_KEY", ""),
+        app.config["HOME_LATITUDE"],
+        app.config["HOME_LONGITUDE"],
+    )
+    for f in forecasts:
+        f["date_obj"] = date_type.fromisoformat(f["date"])
+    return forecasts
+
+
 def get_trip_list() -> list[Trip]:
     """Get trip list with route distances."""
     route_distances = agenda.travel.load_route_distances(app.config["DATA_DIR"])
@@ -674,11 +700,21 @@ def trip_future_list() -> str:
 
     shown = current + future
 
+    trip_weather_map = {
+        trip.start.isoformat(): agenda.weather.get_trip_weather(
+            app.config["DATA_DIR"],
+            app.config.get("OPENWEATHERMAP_API_KEY", ""),
+            trip,
+        )
+        for trip in shown
+    }
+
     return flask.render_template(
         "trip/list.html",
         heading="Future trips",
         trips=shown,
         trip_school_holiday_map=trip_school_holiday_map(shown),
+        trip_weather_map=trip_weather_map,
         coordinates=coordinates,
         routes=routes,
         today=today,
@@ -747,6 +783,12 @@ def trip_page(start: str) -> str:
                 app.config["PERSONAL_DATA"], route.pop("geojson_filename")
             )
 
+    trip_weather = agenda.weather.get_trip_weather(
+        app.config["DATA_DIR"],
+        app.config.get("OPENWEATHERMAP_API_KEY", ""),
+        trip,
+    )
+
     return flask.render_template(
         "trip_page.html",
         trip=trip,
@@ -760,6 +802,7 @@ def trip_page(start: str) -> str:
         holidays=agenda.holidays.get_trip_holidays(trip),
         school_holidays=agenda.holidays.get_trip_school_holidays(trip),
         human_readable_delta=agenda.utils.human_readable_delta,
+        trip_weather=trip_weather,
     )