The one-page reference.
Six sections. The piece every other article on this site links up to. Read once, return when a particular question comes up.
- I.
Sun
Las Vegas sits at 36°10′N. At the June solstice, the noon sun angle hits about 77° — almost directly overhead. The result is that the worst hours of summer are not at noon but in the afternoon, when the sun has dropped below 40° and is hammering west-facing walls and patios at near-perpendicular angle.
The National Weather Service rates UV at index 11+ ("extreme") for roughly six hours a day from May through September in the Mojave. A west-facing patio collects somewhere around 1,800 BTU per square foot on a July afternoon. The four most useful hours of any summer evening are 16:00 to 20:00 — that is the window every other section in this guide is trying to earn back.
- II.
Ground
Three terms cover most of what your contractor sees when they drive a stake into the ground in this valley. Caliche is calcium-cemented desert subsoil — hard as concrete, and it breaks pickaxes. Most footings in Henderson and Summerlin are sunk into caliche, which is why every quote you get for a post-set has a contingency line for substrate. Wash means a dry desert drainage channel; it runs a few times a year, and it tells your installer where your downspouts cannot drain. Slab is the concrete pad your patio lives on, typically poured over a thin layer of fill on top of caliche.
The thing to know: footings cost what they cost because of the ground, not the labor. A four-foot post hole in caliche is half a day of work even with the right tool.
- III.
Wall
A west-facing stucco-on-frame wall in Henderson absorbs solar radiation from roughly 14:00 until sunset, then releases it as long-wave heat into the evening. By the time the patio underneath is finally usable, around 21:00 in mid-July, the wall is still throwing 8-12°F of radiant heat into anyone sitting near it. That is the reason a perfectly shaded patio still feels warm an hour after sundown.
Mass changes the timing. Adobe, rammed earth, and CMU walls lag six to eight hours — they reach peak temperature near midnight and are radiating cold at dawn. Most valley homes do not have mass walls. Knowing what your wall is made of tells you which problem you are solving.
- IV.
Cover
Four common patio covers, ranked by how much they lower the dry-bulb air temperature underneath them on a July afternoon:
- Solid roof: approximately 9°F drop. Traps a stagnant pillow of hot air directly above the people sitting under it.
- Lattice / pergola: about 11°F. Architectural; mediocre as shade.
- Shade sail (PE fabric): 14–18°F. Inexpensive, replaces every 3–5 years.
- Aluminum mesh: 18–22°F. Permeable to wind; the argument of this magazine.
For west-facing exposures, the serious answer is mesh on top with a drop-shade on the western side. The mesh defeats the high-angle midday sun; the drop-shade kills the low-angle four-o'clock sun.
- V.
Air
Most valley evenings produce a roughly twenty-minute window — usually beginning shortly after sunset — when the air actually moves. The desert cools faster than the city; the pressure gradient drives wind down out of the Spring Mountains and across the basin. If you have a permeable cover and a clear cross-ventilation path, the patio drops 6–10°F in those twenty minutes. If you do not, it does not.
Misters are the wrong answer for this climate, even though they appear at every patio store in the valley. They add humidity to dry air; without strong cross-ventilation, that humidity hangs and the patio feels worse rather than better. The right tool for desert cooling is moving air, not water suspended in it.
- VI.
Plant
Three desert plants are worth shaping a backyard around. The Joshua tree is not a tree — it is a yucca, with a hundred-year lifespan and a single specialist pollinator (the yucca moth). It does not transplant well over a foot tall; if you want a Joshua tree in your yard, get one small or buy a house with one already there. The mesquite sends a tap root forty feet down into caliche cracks, fixes nitrogen, and casts the most useful filtered shade in the valley. The palo verde, the Arizona state tree, photosynthesizes through its green bark — it can survive without leaves for months and is the right answer for a low-water front yard with afternoon sun.
This guide is the substrate. Everything in Field Notes is a measurement against it; everything in the Glossary is a term that appears here. Send corrections to the editor.