It gets “dark” shortly after your local sunset time, usually within about 30–60 minutes, depending on where you are and the season.

What “dark” actually means

  • Sunsets mark when the Sun disappears below the horizon, but there is still some light during twilight.
  • Astronomers split twilight into three stages: civil (still fairly light), nautical (quite dim), and astronomical (truly dark sky).

Example for today (reference city)

  • For a mid‑latitude city like London on December 30, 2025, sunset is around 16:00, and night (full darkness after astronomical twilight) begins a little after 18:00.
  • That means it feels noticeably dark to most people roughly 30–40 minutes after sunset, and fully dark for stargazing about 2 hours after sunset.

How you can check for your location

  • Search for “sunrise sunset today” plus your city (for example, “sunrise sunset today Chicago”).
  • Many sunrise/sunset calculators also list civil, nautical, and astronomical twilight, so you can see exactly when it will be fully dark.

Seasonal and location effects

  • In winter at higher latitudes (like northern Europe or Canada), it gets dark very early in the afternoon, and twilight is relatively short.
  • In summer or closer to the poles, the Sun may set very late, and twilight can last so long that it never becomes completely dark at night.

In everyday terms: expect it to feel “dark” roughly half an hour after your local sunset, and truly night‑dark about 1.5–2 hours after, with the exact timing depending on your city and date.

TL;DR: Look up today’s sunset time for your city; add ~30–60 minutes for it to feel dark, and up to ~2 hours for full night.

Information gathered from public forums or data available on the internet and portrayed here.