How many hours of daylight in a UK summer?

The longest day (21 June) gives approximately 16.5 hours in southern England and 18+ hours in northern Scotland. From May to July, there is ample daylight for long mountain days. Shetland experiences near-constant daylight (simmer dim) around the solstice.

How many hours of daylight in a UK winter?

The shortest day (21 December) gives about 7.5 hours in southern England and less than 6.5 hours in northern Scotland. From November to January, careful planning is essential — a 6-hour hike starting at 09:00 uses almost all available daylight.

What is usable hiking time?

Usable hiking time is daylight minus approximately 1.5 hours — accounting for travel to the start, the dimming light at dusk, and a safety margin. In winter, this gives very limited time. In summer, you may have 14+ hours of usable hiking time.

Should I carry a head torch even in summer?

Yes, always. Even in summer, delays can push your finish time into dusk. Navigation errors, injuries, or slower-than-expected pace can all extend your day. A head torch weighs 50-100g and could save your life. Always carry one as part of your essential kit.

CampCalcs

Daylight Hours Calculator

Calculate hours of daylight for any date and UK location for trip planning.

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Day

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How We Calculate This

Daylight Calculation

Declination = 23.45 x sin(360/365 x (day_of_year - 81))

Hour angle = arccos(-tan(latitude) x tan(declination))

Daylight = 2 x Hour angle / 15 (hours)

Usable Hiking Time

Usable time = Daylight - 1.5 hours (safety margin for dusk and travel).

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.