Fraxle
8f161dc8cb
Summaries added — every column in COL_DESCRIPTIONS got a short (1–2 sentences) and a link to its reference row. Full desc text kept intact for the day-tab metric labels. Popup rewired — renders the summary plus a "More about this column →" link, opening in a new tab. Link styling — .col-info-more pinned below the summary so it stays visible if the text scrolls; centred on mobile with the rest. Anchors on the reference page — 35 row ids in columns.html, one per column key. New "Rows" row — the hour/interval header had a popup but no matching row on the reference page; added. Landing highlight — tr:target gets a gold bar and tint, with scroll offset so the nav doesn't cover it.
181 lines
12 KiB
HTML
181 lines
12 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="UTF-8" />
|
||
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
|
||
<title>Derived temperatures · SunScope</title>
|
||
<meta name="description" content="How SunScope models the temperatures the thermometer doesn't show — a parked vehicle's interior, a building's indoor temperature without air conditioning, and sun-baked urban concrete." />
|
||
<meta name="robots" content="index, follow" />
|
||
<link rel="canonical" href="https://sunscope.net/temperatures.html" />
|
||
|
||
<meta property="og:title" content="Derived temperatures · SunScope" />
|
||
<meta property="og:description" content="The physics-based temperature models behind SunScope: vehicle interior, indoor building temperature, and urban concrete surface temperature." />
|
||
<meta property="og:url" content="https://sunscope.net/temperatures.html" />
|
||
<meta property="og:type" content="article" />
|
||
<meta property="og:image" content="https://sunscope.net/og-image.png" />
|
||
<meta name="twitter:card" content="summary_large_image" />
|
||
<meta name="twitter:title" content="Derived temperatures · SunScope" />
|
||
<meta name="twitter:description" content="The physics-based temperature models behind SunScope: vehicle interior, indoor building temperature, and urban concrete surface temperature." />
|
||
<meta name="twitter:image" content="https://sunscope.net/og-image.png" />
|
||
|
||
<link rel="icon" type="image/svg+xml" href="./favicon.svg" />
|
||
<link rel="stylesheet" href="./assets/about.css?v=15b">
|
||
|
||
<script type="application/ld+json">
|
||
{
|
||
"@context": "https://schema.org",
|
||
"@type": "Article",
|
||
"headline": "Derived temperatures",
|
||
"about": "Vehicle interior, indoor building, and urban concrete temperature models in SunScope.",
|
||
"publisher": { "@type": "Organization", "name": "SunScope", "url": "https://sunscope.net" },
|
||
"mainEntityOfPage": "https://sunscope.net/temperatures.html"
|
||
}
|
||
</script>
|
||
</head>
|
||
<body>
|
||
|
||
<header id="site-nav">
|
||
<div class="nav-overlay" onclick="toggleNav(false)"></div>
|
||
<a href="./index.html" class="logo"><span class="logo-sun">Sun</span><svg class="logo-icon" viewBox="0 0 174 173" aria-hidden="true" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:1.5;"><g transform="matrix(0.986226,0,0,0.986226,-585.724252,-110.041209)"><clipPath id="ss-clip-te"><circle cx="681.9838" cy="199.4502" r="83.2987"/></clipPath><g clip-path="url(#ss-clip-te)"><g transform="matrix(0.948836,0,0,0.948836,19.787839,-2.49381)"><path d="M666.992,233.0768C666.3949,230.6581 666.1785,228.6317 666.1785,226.0296C666.1785,208.6786 680.2653,194.5919 697.6163,194.5919C714.9672,194.5919 729.054,208.6786 729.054,226.0296C729.054,228.4125 728.9892,230.9346 728.4859,233.1663" fill="none" stroke="#c8922a" stroke-width="7.48"/></g><g transform="matrix(0.520349,0,0,0.520349,304.766642,64.226716)"><path d="M724.9315,291.8131C777.359,291.8131 826.5862,305.6245 869.1698,329.8044" fill="none" stroke="currentColor" stroke-width="13.64"/></g><g transform="matrix(0.520349,0,0,0.520349,304.766642,64.226716)"><path d="M580.8436,329.719C623.3927,305.592 672.5657,291.8131 724.9315,291.8131" fill="none" stroke="currentColor" stroke-width="13.64"/></g></g><circle cx="681.9838" cy="199.4502" r="83.2987" fill="none" stroke="currentColor" stroke-width="9.13"/></g></svg><span class="logo-scope">Scope</span></a>
|
||
<div class="nav-links" id="nav-drawer">
|
||
<a href="./index.html">Forecast</a>
|
||
<div class="nav-dropdown">
|
||
<a href="./about.html" class="nav-dropdown-toggle active">About<span class="caret">▾</span></a>
|
||
<div class="nav-dropdown-menu">
|
||
<a href="./about.html">Overview</a>
|
||
<a href="./sunsoak.html">SunSoak & the science</a>
|
||
<a href="./profiles.html">Forecast profiles</a>
|
||
<a href="./columns.html">Column reference</a>
|
||
<a href="./temperatures.html" class="active">Derived temperatures</a>
|
||
<a href="./features.html">On-screen features</a>
|
||
<a href="./stress-bands.html">Stress bands</a>
|
||
</div>
|
||
</div>
|
||
<a href="./faq.html">FAQ</a>
|
||
<a href="https://billing.stripe.com/p/login/9B63cw7vl8k15Ei9DQd7q00" target="_blank" rel="noopener noreferrer">Account</a>
|
||
</div>
|
||
<button class="utci-burger" aria-label="Open menu" aria-expanded="false" id="burger-btn" onclick="toggleNav()">
|
||
<span></span><span></span><span></span>
|
||
</button>
|
||
</header>
|
||
<script>
|
||
function toggleNav(force) {
|
||
const nav = document.getElementById('site-nav');
|
||
const drawer = document.getElementById('nav-drawer');
|
||
const btn = document.getElementById('burger-btn');
|
||
const open = force !== undefined ? force : !nav.classList.contains('nav-open');
|
||
nav.classList.toggle('nav-open', open);
|
||
drawer.classList.toggle('is-open', open);
|
||
btn.setAttribute('aria-expanded', open ? 'true' : 'false');
|
||
}
|
||
</script>
|
||
|
||
<main>
|
||
<h1>Derived temperatures</h1>
|
||
<p class="tagline">The temperatures the thermometer never tells you.</p>
|
||
|
||
<p>
|
||
Beyond felt temperature, SunScope runs three physics-based models that estimate temperatures you
|
||
can't read off a standard forecast: how hot a parked vehicle becomes, how warm a building stays
|
||
indoors, and how sun-baked urban concrete gets. Each is built on the same per-hour weather data.
|
||
</p>
|
||
|
||
<h2>Vehicle interior temperature</h2>
|
||
<p>
|
||
A sealed, parked vehicle heats up far faster than most people expect. SunScope's <strong>Vehicle</strong>
|
||
column models the ambient cabin air temperature experienced by an occupant seated out of direct
|
||
sunlight — the classic scenario of a child or pet left inside a parked car.
|
||
</p>
|
||
<p>
|
||
The calculation combines two physical processes. The first is <strong>body panel conduction</strong>:
|
||
panels absorb solar radiation and conduct heat into the cabin regardless of the sun's position. Thin
|
||
metal car panels pass much more of this through than the insulated sandwich panels of many motorhomes
|
||
and caravans. This is the slow, relentless background heat that builds even on overcast days. The
|
||
second is <strong>side-window solar gain</strong>: when the sun's rays cut through the side glass
|
||
rather than striking the roof, additional heat enters the cabin. Because the occupant sits out of the
|
||
direct beam, this energy raises the ambient cabin air temperature rather than heating the person
|
||
directly — which is precisely what makes it so dangerous.
|
||
</p>
|
||
<p>
|
||
You can select your vehicle type (car, MPV, SUV, truck/HGV cab, motorhome, or caravan), each with
|
||
its own albedo, glazing area, and insulation. A <em>Windows open</em> toggle switches to a
|
||
ventilated model where convective loss is roughly five times higher, dramatically reducing cabin
|
||
heat build-up. For cars, the figure represents the cabin after roughly 45–60 minutes of parking;
|
||
motorhomes and caravans are treated as insulated occupied living spaces, so the estimate stays
|
||
closer to the real living-space temperature on cool or moderate sunny days. Values above 35 °C are
|
||
shown in amber (dangerous for children and pets); above 45 °C in red (potentially fatal within
|
||
minutes).
|
||
</p>
|
||
<p>
|
||
A <strong>road speed</strong> selector — Static, Urban (20 mph), A-road (50 mph), or Motorway
|
||
(70 mph) — sits alongside the ventilation toggle. Static reproduces the original stationary model;
|
||
higher speeds add forced airflow that scrubs heat off the bodywork, and when combined with windows
|
||
open, flush the cabin toward outside air much faster than a parked vehicle. Wind speed itself has
|
||
almost no effect on a sealed, stationary vehicle and is only meaningfully factored in through
|
||
ventilation or road speed.
|
||
</p>
|
||
|
||
<h2>Indoor temperature</h2>
|
||
<p>
|
||
The <strong>Indoors</strong> column estimates the temperature inside a building with windows closed
|
||
and no air conditioning, simulating retained warmth, window solar gain, internal gains, and thermal
|
||
mass hour by hour. You choose your building type from a dropdown — brick, modern insulated, Victorian
|
||
terrace, stone cottage, timber frame, top-floor flat, conservatory, or office block — and the physics
|
||
model adjusts accordingly. Each type has its own insulation level, thermal mass, retained warmth, and
|
||
glazing, so a stone cottage and a conservatory behave very differently on a hot day. Office block
|
||
carries a higher internal gain (people, equipment, lighting) and more glazing than a typical home,
|
||
reflecting a commercial building rather than a house.
|
||
</p>
|
||
<p>
|
||
The model lags toward a realistic hourly target rather than repeatedly adding solar heat, so indoor
|
||
temperatures typically peak 2–4 hours after the outdoor peak — which is why a house can still feel
|
||
stifling at 10 pm on a summer day. Tick <em>Managed</em> alongside the dropdown to switch to the
|
||
heatwave-advice model: curtains closed by day to cut solar gain, windows opened whenever outdoor air
|
||
is cooler than inside. The <strong>Managed</strong> column shows how much passive cooling can reduce
|
||
indoor heat compared to doing nothing.
|
||
</p>
|
||
|
||
<h2>Urban concrete surface temperature</h2>
|
||
<p>
|
||
The UTCI standard was developed with a natural grass surface as its reference ground. In a city that
|
||
assumption breaks down. Concrete and tarmac absorb far more solar energy than grass, and unlike grass
|
||
they have no evaporative cooling. On a sunny summer afternoon, exposed paving can run 15–25 °C hotter
|
||
than the surrounding air.
|
||
</p>
|
||
<p>
|
||
SunScope's <strong>Concrete surface</strong> column estimates the temperature of sun-exposed urban
|
||
paving using a surface energy-balance model that accounts for how much solar radiation the surface
|
||
absorbs, how efficiently the wind carries that heat away, and the reflective properties of typical
|
||
urban concrete. The result gives a sense of the contact heat stress you'd experience sitting,
|
||
standing, or walking barefoot on city surfaces — and it's a useful proxy for pavement-paw safety for
|
||
dogs. The column is enabled by default in the <strong>Places → Urban</strong> view and colour-coded:
|
||
values above 30 °C are shown in amber, above 40 °C in red.
|
||
</p>
|
||
|
||
<h2>Pet fur and paw temperatures</h2>
|
||
<p>
|
||
The <strong>Pets</strong> profile runs two further physics estimates alongside the shade and
|
||
indoor models. <strong>Fur Temp</strong> estimates the surface temperature of a cat or small dog's
|
||
coat sitting in direct sun, calibrated for a thin/short coat rather than a heavily-insulated breed.
|
||
A <strong>fur colour</strong> selector (Black/Dark, Brown/Tabby, Golden/Tan, White/Pale) sets the
|
||
coat's albedo — darker coats absorb more solar radiation and run hotter, the same principle as
|
||
Shade Air but applied to fur rather than skin. <strong>Paw Temp</strong> reuses the concrete
|
||
surface energy-balance model above to estimate ground contact temperature, colour-coded by burn
|
||
risk instead of the general amber/red thresholds: green below 40 °C, amber 40–52 °C, red above
|
||
52 °C.
|
||
</p>
|
||
|
||
<p>
|
||
These columns appear together in the <a href="./profiles.html">Temps profile</a>. For what every
|
||
column means, see the <a href="./columns.html">column reference</a>.
|
||
</p>
|
||
|
||
</main>
|
||
|
||
<footer>
|
||
© 2026 <a href="https://fraxle.net" target="_blank" rel="noopener noreferrer">Fraxle.NET</a> · <a href="./index.html">Forecast</a> · <a href="./about.html">About</a> · <a href="./faq.html">FAQ</a> · <a href="https://billing.stripe.com/p/login/9B63cw7vl8k15Ei9DQd7q00" target="_blank" rel="noopener noreferrer">Account</a> · Data: <a href="https://open-meteo.com/" target="_blank" rel="noopener noreferrer">Open-Meteo</a> · UTCI: <a href="https://utci.org/" target="_blank" rel="noopener noreferrer">Bröde 2012</a>
|
||
</footer>
|
||
|
||
</body>
|
||
</html>
|