Sarasota Pool Deck Surface Temperature Study: the protocol, published before the numbers
Nine surfaces, three times, two seasons, one thermometer. No temperature is quoted here until it's been measured.
- Surfaces
- 9
- Times
- 10 a.m., 2 p.m., 5 p.m.
- Days
- One clear July day, one clear January day
- Instrument
- Calibrated infrared thermometer
- Status
- Protocol published; readings pending
What is the Sarasota Pool Deck Surface Temperature Study?
A side-by-side measurement of nine pool deck surfaces (gray and light broom concrete, a cool-deck overlay, gray and light concrete pavers, tumbled travertine, shellstone, honed marble and 2 cm porcelain) with a calibrated infrared thermometer at 10 a.m., 2 p.m. and 5 p.m. on one clear July day and one clear January day in Sarasota, with air temperature, sky, wind and surface condition recorded. The protocol is published now; the readings are published the day they exist.
Measurement dates are set for January 2027 and July 2027. The results go on this page as a table and to /api/surface-temperatures.json under a CC BY 4.0 license, and the comparison pages and the surface selector will switch from physics-based ordering to measured values.
Protocol
- Samples of each surface, minimum 12 by 12 inches, laid side by side on the same compacted base in full sun, dry, at least 48 hours after rain.
- Infrared thermometer with emissivity set for masonry (about 0.94), held at the instrument's specified distance, perpendicular to the surface.
- Three readings per surface per time, taken within two minutes; the median is recorded.
- Shaded air temperature, sky condition, wind and time since last rain recorded at each session.
- Sessions at 10:00, 14:00 and 17:00 local time.
- One clear day in July and one in January; if clouds interrupt, the session is repeated on the next clear day.
- Raw readings, medians and conditions published as JSON; nothing averaged across days.
Surfaces
| Surface | Color class | Why it's in the study |
|---|---|---|
| Gray broom-finished concrete | medium | |
| Light (white cement) broom-finished concrete | light | |
| Light textured cementitious overlay (cool deck type) | light | |
| Gray concrete paver | medium | |
| Light-blend concrete paver | light | |
| Tumbled travertine, light | light | |
| Shellstone | light | |
| Honed marble, white/cream | light | |
| 2 cm porcelain paver, light | light |
What the physics predicts (not data)
Solar reflectance and thermal mass explain most of the difference between surfaces in the sun: light colors reflect more, porous stone sheds heat and holds a little moisture, thin dense tile heats and cools fast. The surfaces and heat comparison lays out the expected order and labels it as expected. Manufacturer and blog claims of 20 to 35 degree differences are not reproduced here as measurements.
Results
Download
surface-temperatures.json (protocol now; readings when measured; CC BY 4.0).
Questions we get about this
Which pool deck surface stays coolest barefoot in Sarasota in July?
This site will answer with its own measurement in July 2027 and won't guess before then. The physics says light, porous surfaces (tumbled travertine, shellstone) will read lowest and dark dense surfaces (charcoal pavers, gray concrete) highest, with light concrete, light pavers and porcelain between. The comparison page explains why; the numbers arrive with the study.
How hot does a gray concrete pool deck get at 2 p.m. in August in Sarasota?
Unmeasured locally, which is why this study exists. Published claims from other parts of Florida put gray concrete well above 130 degrees on a 95-degree afternoon; those are not reproduced here as data.
Why not just quote the manufacturer numbers?
Because they're measured elsewhere, under conditions that aren't stated, by people selling the product. A Sarasota reading with the instrument, time, sky and air temperature recorded is worth more than a hundred of them.
The full protocol, published before the data exists
Publishing a method in advance is a commitment that the results cannot be shaped after the fact. This is the complete protocol.
| Element | Specification |
|---|---|
| Surfaces, nine | Gray broom concrete; light broom concrete; cool-deck overlay; gray concrete paver; light concrete paver; tumbled travertine; shellstone; honed marble; 2 cm porcelain |
| Sample preparation | Each material laid on the same compacted base in the same open location, minimum 24 by 24 inches, fully sun-exposed, dry, no shading from structures or planting |
| Instrument | Calibrated infrared thermometer, emissivity set for masonry, recorded model and calibration date |
| Readings | Three per surface per time slot; median reported; ambient air temperature, sky condition and wind noted |
| Time slots | 10:00, 14:00 and 17:00 local time |
| Days | One clear July day and one clear January day, both recorded with date and conditions |
| Publication | Table on this page, medians and raw readings, plus JSON at the API endpoint under CC BY 4.0 |
| Scheduled | January 2027 and July 2027 |
Why an infrared thermometer and not a probe
The question a homeowner is asking is what the surface does to the sole of a foot, which is a surface-temperature question, not a bulk-material one. An infrared thermometer reads the surface directly and can sample nine materials in under two minutes, which keeps the readings comparable because the sun has barely moved between them.
Its weakness is emissivity: an infrared reading depends on an assumed surface emissivity, and a polished surface reads low. That is why the protocol sets emissivity for masonry, reports the instrument and its calibration date, and takes three readings per surface. It is also why honed marble and porcelain will carry a note in the results: they are the two surfaces where the instrument is least comfortable, and a contact measurement may be added for them.
What the study will not claim is how a deck feels. Perceived heat depends on conductivity and contact area as much as on temperature, which is why a porous travertine at 118 degrees can feel better than a dense porcelain at the same reading. The temperature table is one input into that, and the page will say so.
What is published today
The protocol above, and nothing else. No temperature figure appears on this site attributed to this study until the readings exist, and no vendor figure is adopted as though it were ours.
The physics of why surfaces differ is on the surface heat comparison, which also attributes the circulating Florida vendor figures to their source and explains why they are not treated as measurements. The method for every dataset on this site is on data and methods.
Last reviewed September 10, 2026 by the Sarasota Concrete editorial team (author name pending owner input). Protocol published; no readings yet.