When we tell you a beer garden has 85% sun right now, that's not a guess. It's a real-time calculation based on astronomy, geography, and a lot of walking around Lancaster with a compass. This is the full behind-the-scenes explanation of how the Golden Pints sun tracker actually works — because we think it's genuinely interesting, and because we want you to understand why our scores are more reliable than anything else out there.
The Problem We're Solving
Most pub review sites tell you a garden is 'south-facing' and leave it at that. But that single descriptor hides enormous variation. A south-facing garden can be in full direct sun at 1pm in July and in deep shade at 1pm in December. It can catch sun all afternoon if the surrounding area is open, or get blocked by a neighbouring building by 2pm. And 'south-facing' tells you nothing about east or west — some of the best afternoon sun comes from south-west facing gardens that traditional descriptions would just call 'facing south'.
We wanted to build something genuinely useful: a tool that tells you right now, not in general, which beer garden in Lancaster has the most sun. That requires real data, real calculation, and a lot of legwork.
Step 1: We Verify Gardens in Person
Before sun scoring goes live for a garden, a member of the Golden Pints team visits it in person. We do this with a compass, a notebook, and usually a pint to make the process more enjoyable.
We measure two key things for each garden: compass bearing (the direction the garden faces, measured in degrees from north — 0° is north, 90° is east, 180° is due south, 270° is due west) and opening angle (how wide the garden's view of the sky is). A garden in a narrow courtyard has a small opening angle and might only get sun when the sun is directly overhead. A garden on an open hillside with no obstructions has a wide opening angle and catches sun across a much broader range of times.
We've now verified 33+ pubs across Lancaster city centre, Morecambe, Hest Bank, Bolton-le-Sands, Carnforth, Glasson Dock, and the surrounding area. Newer listings stay marked as visit-pending until their garden has been measured in person. No shortcuts.
Step 2: Real-Time Solar Calculations
With each garden's GPS coordinates, bearing, and opening angle in hand, we calculate whether the sun is shining on it right now using real solar astronomy — specifically the SunCalc library, a well-tested JavaScript implementation of solar position algorithms.
This gives us two numbers updated every minute: solar altitude (how high the sun is above the horizon — at noon on a summer day in Lancaster, roughly 55°; in midwinter, barely 15°) and solar azimuth (which direction the sun is facing, in degrees from north). The sun rises in the east and sets in the west, but the exact azimuth changes significantly across the year.
Step 3: Is the Sun Within the Garden's View?
With the sun's azimuth in hand, we ask: is the sun currently within the garden's opening angle? Here's a simplified example. The Water Witch faces south-west (225°) with an opening angle of 140°. That means it can 'see' the sun from roughly 155° to 295°. When the sun's azimuth is within that range and the altitude is above the horizon, the garden is in direct sunlight. When the sun falls outside that range, it's in shade.
The Three Mariners, by contrast, faces south-southeast (160°) with a smaller opening angle of 80° — meaning it can see the sun from about 120° to 200°. This gives it a shorter window of direct sunlight, which matches what you experience in the courtyard: a morning-to-early-afternoon sun trap rather than an all-day one.
Step 4: Calculating the Sun Score
The sun score (0–100%) isn't just a binary in-sun/out-of-sun calculation. It reflects how directly the sun is hitting the garden right now. When the sun is at the optimal angle for a garden — right in the middle of its bearing, at a good altitude — the score is close to 100%. As the sun moves towards the edge of the garden's visible arc, or as it gets lower in the sky, the score decreases. When the sun falls outside the garden's view entirely, the score is 0%.
This means scores are comparable across gardens. An 80% score means roughly the same quality of sunshine wherever you see it on the tracker.
Step 5: Golden Hour Detection
We also calculate golden hour — the period just before sunset when the sun's light turns warm and amber. During golden hour, west-facing gardens get a special badge on the tracker. Gardens like The Water Witch (bearing: 225°), The George & Dragon (bearing: 210°), and The Hest Bank Inn (bearing: 270°) are the golden hour specialists — all west or south-west facing, all with settings where the evening light is part of the reason to stay out.
Why This Approach Beats 'South-Facing' Labels
The key advantage is that it's time-specific. We don't tell you a garden is good for sun in general — we tell you whether it has sun right now, and how much. You can check before you leave the house. You can plan ahead (the sun's position is mathematically predictable). And when the sun's not out, Cosy Mode kicks in and ranks gardens by all-weather features instead.
No other resource in Lancaster does this. Google tells you a garden is 'south-facing'. We tell you it has 73% sun right now and will peak at 2:30pm. That's the difference between a guess and a plan.
The Ongoing Work
The measurements are only as good as the underlying data. We revisit gardens when pubs make changes — new structures, extensions, or removed trees can all change a garden's effective opening angle. As Golden Pints grows beyond Lancaster, every new city gets the same treatment: personal visits, careful measurements, and the same real-time calculation. The goal is a tracker that works the same way in Preston, Manchester, or Leeds as it does in Lancaster.
Want to see the scores for Lancaster's beer gardens right now? Visit goldenpints.co.uk — it's free, works on any device, and updates every 60 seconds.
What We Don't Calculate (and Why)
It's worth being honest about what the sun tracker doesn't account for. We don't model neighbouring building shadows in real time — if a new extension blocks part of a garden's sky, we update our opening angle data on the next verification visit, not instantly. We also don't account for cloud cover: our scores reflect what the sun position would produce on a clear day. On an overcast day, Cosy Mode is more useful than sun scores.
And we don't claim perfection. Solar astronomy is precise, but the real world isn't. A garden that scores 95% on the tracker might have a tree that we measured incorrectly, or a building that went up after our last visit. We revisit gardens regularly and update the data when things change.
What we do claim is that our scores are more reliable than anything else available for Lancaster beer gardens — and that they get better over time as we refine our measurements and add more verified data.
Try It for Yourself
The best way to understand how the tracker works is to use it. Check goldenpints.co.uk on a sunny afternoon and compare the top-scoring pubs against where the sun actually is in the sky. You'll quickly see the correlation — south-facing gardens dominating at lunchtime, west-facing gardens coming into their own as the afternoon turns to evening, and the golden hour badges appearing in the right places at the right time.
If you spot something that doesn't match your experience — a garden that consistently underperforms or overperforms its score — let us know. We update the data. That's how it gets better.