> For the complete documentation index, see [llms.txt](https://support.waderaviation.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.waderaviation.com/reference/night-time-calculation.md).
# Night Time Calculation
Wader automatically calculates night time based on the **apparent sunset and sunrise** at your departure and arrival airports, using the **NOAA Solar Calculator** methodology.
Night time is the portion of your block time that falls after sunset at the departure airport or before sunrise at the arrival airport, whichever applies.
## Civil twilight
Civil twilight is **not currently used** in Wader's night time calculation — this is a planned future enhancement. In practice, this typically results in a difference of 20–30 minutes per flight compared to civil twilight-based calculations.
## Manual adjustment
If you need to set night time manually — for example, to match a different regulatory standard:
1. Open the flight and save it first.
2. Tap **Edit Times**.
3. Enter your night time value directly.
{% hint style="warning" %}
Save the flight before using Edit Times. Unsaved changes may be lost when switching to the time editor.
{% endhint %}
## Turning off auto night calculation
Auto night calculation can be turned off in **Preferences**. When off, you enter night time manually on every new flight.
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