Historical weather overlay on map

[bgorzelic]

Description

Add the ability to overlay historical weather data on the hazard map, allowing users to view conditions at the time an observation was recorded. This helps with after-action analysis and training.

Proposed Implementation

Data Source

• Open-Meteo Historical API: free, no API key, supports any date back to 1940
• https://archive-api.open-meteo.com/v1/archive?latitude=X&longitude=Y&start_date=YYYY-MM-DD&end_date=YYYY-MM-DD&hourly=temperature_2m,relative_humidity_2m,wind_speed_10m,wind_direction_10m

Map Features

• Time slider control on map to scrub through historical weather
• Wind barb overlay showing direction and speed at observation times
• Temperature/RH heatmap layer for historical conditions
• Side-by-side comparison: recorded observation vs. historical weather data

UI

• "Weather History" toggle in map layer panel
• Date/time picker synced with observation timestamps
• Legend showing color scales for temperature, humidity, wind

Acceptance Criteria

• Historical weather data fetched for observation dates
• Wind direction/speed visualized on map
• Temperature/RH overlay available
• Time slider allows scrubbing through history
• Data loads without blocking map interaction
• Works with the existing dark map style