Gray Line & Aurora Map
Where it's day, night and twilight right now, with the live aurora forecast.
Shading darkens through civil, nautical and astronomical twilight. Updates every minute.
About this tool
What is the gray line?
The band of twilight between day and night. Along it, the lower HF bands (160–40 m) absorb less in the D layer while the upper layers are still ionised, so signals can travel unusually far. Contacts between two stations that are both in the gray line can work with very little power.
Aurora
The green-to-red glow shows NOAA's OVATION model: the chance of seeing the aurora overhead in the next half hour or so. Strong aurora also opens VHF "auroral" propagation and disturbs HF polar paths. Check the Kp index on the HF Propagation page.
Data
Day/night is calculated in your browser from the Sun's position. Aurora forecast: NOAA Space Weather Prediction Center, refreshed every 15 minutes. Map tiles: OpenStreetMap and CARTO.