Weather Forecasts
- NOAA/NWS forecastHourly: Primary forecast source for near-term predictions (0-6.5 days). Provides hourly temperature, wind speed/direction, and detailed weather conditions. Updated multiple times daily. Accessed via Weather.gov API.
- Open-Meteo: Extended range forecast source (0-16 days). Uses ensemble models combining GFS, ECMWF, and other global weather models. Provides hourly forecasts with WMO weather codes. Accessed via Open-Meteo API.
- Tiered System: When race is within 6.5 days, both NOAA and Open-Meteo forecasts are available for comparison. Beyond 6.5 days, only Open-Meteo is available. NOAA is generally preferred for short-term accuracy.
Historical Climatology
- Start Location (Folsom): 10 years of observations (2015-2024) from Mather Airport (MHR), ICAO identifier KMHR, located approximately 5 miles from the start line. Data shows conditions at 7:00 AM PST on December 7.
- Finish Location (Sacramento): 10 years of observations (2015-2024) from Sacramento International Airport (SAC), showing both start time and variable finish time conditions based on your target pace. Demonstrates typical temperature rise and wind pattern changes throughout the race.
- Data Source: All climatology data from Iowa State University IEM ASOS Archive, which provides quality-controlled ASOS/AWOS observations from automated airport weather stations.
Route & Elevation Data
- Course Route: Officially published GPS coordinates from race organizers showing the certified 26.2-mile point-to-point course from Folsom to Sacramento.
- Elevation Profile: Extracted from Mapbox Terrain-RGB tileset at zoom level 13, providing approximately 10-meter resolution. Shows the net ~200ft descent from Folsom (elevation ~230ft) to Sacramento (elevation ~30ft).
- Station Locations: Mile markers, 5K splits, and official aid station coordinates along the race route. Each station is geocoded for precise weather forecast retrieval.
Mapping & Visualization
- Base Maps: OpenStreetMap tiles for street-level detail
- Interactive Features: Leaflet.js for map rendering and marker interactions
- Elevation Charts: Chart.js for responsive elevation profile visualization
Note on Data Accuracy: Weather forecasts are inherently uncertain and become less accurate with increasing lead time. Historical climatology provides context but does not guarantee similar conditions for race day. Elevation data is accurate to ±10 meters. Use this tool as planning guidance, not as definitive race day predictions.