Solar Data

As a convenience, AvnWx.com calculates sunrise and sunset for each weather reporting station. This data is viewable in the METAR or TAF detailed window: Select a METAR or TAF and the data is shown at the bottom of the pop-up window. Note the data is not shown in the window on just a mouse rollover, you must click on the METAR (or TAF) symbol to view the data. (See Controls Help -- Info Windows to review the difference between rollover enabled versus rollover disabled popup Info Windows.)

Aircraft position lights are required to be used from sunset to sunrise (FAR Part 91.209)

By definition (FAR Part 1 Sec. 1.1 General definitions.) "Night" means the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac. As the almanac is no longer published, this definition is not particularly useful. This time is used for Logging flight time. (FAR Part 61.109).

Recall that currency and passenger carrying requirements are based on no later than one hour after sunset to one hour before sunrise. (FAR Part 61.57).

Solar data is accurate to within a few minutes, based on latitude/longitude of the station: It does not take into consideration elevation of the station or surrounding environment, so check local listings if you need to-the-minute accuracy.

Sunrises / sunsets change by only a few minutes day-to-day. A strict reading of the Regulations imply the following.

HOWEVER, a more conservative and safety-conscious approach would be to ignore the "Civil Twilight" category and log night time only in the hour after/ hour before period, and require VFR night equipment between sunset/sunrise:

Lunar Data

Lunar data is also calculated, and shown with the Solar data.

Lunar data is accurate to within a few minutes, based on latitude/longitude of the station. Moon rise changes by about 45 minutes each day. For this reason, AvnWx.com calculates lunar events for today and tomorrow (and yesterday if applicable). If no time is listed for today or tomorrow, then the moon doesn't change that day (it either remains visible or under the horizon after midnight).

Algorithms for calculating solar and lunar events are derived from NOAA Earth System Research Lab, and US Naval Observatory

More information is available on the map's Forms and Controls, on the map's icons, and on the data sources.

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