Nautical Twilight Schedule
Generate a yearly streetlight operating schedule for any location. Returns daily nautical dusk (lights ON) and nautical dawn (lights OFF) times.
The placeholder coordinates (36.7456, −93.4712) are the US Census population-weighted centroid for the United States, near Hartville, MO — useful for understanding average streetlight operating times across the country. For regional analysis (e.g., crashes in Kansas or the Denver metro area), use a state or metropolitan area population-weighted centroid from the same Census reference. Streetlights turn ON at −6° sun elevation (end of civil twilight) and OFF at −6° (start of civil twilight).
Phase Calculator
Upload a CSV with coordinates and timestamps. Each record gets tagged with sun elevation, twilight phase, and streetlight status.
1. Upload CSV
Drop a .csv file here or
Maximum 2.5 million rows
Try it with sample data:
2. Map Columns
Confirm which columns contain your location and date/time fields.
3. Processing
Splitting and processing your data...