Phoenix · Maricopa County · Arizona

A working reference for the Phoenix desert

Heat safety, monsoon storms, desert yards and gardens, homes and pools: the four things that decide how a year here actually goes. Every figure on this site traces to an official record and carries the date it was checked.

Station: USW00023183 Sky Harbor
Days above 100 °F: 111 normal year
Normal July high: 106.5 °F 1991–2020
Normal rain: 7.22 in per year

Heat-safe hours

November

All day

All 24 hours

Every hour of a typical November day sits below 90 °F, the ceiling this site sets for yard work or a dog walk. The day peaks at a heat index of about 75 °F around 3:00 PM MST, and no hour needs avoiding on heat grounds.

Each bar is the NWS heat category for that hour. The green outline marks the hours that stay below your ceiling of 90 °F for yard work or a dog walk.

Open the full planner · NOAA 1991–2020 hourly normals, Phoenix Sky Harbor

Tools, filed by what you are trying to do

Reference

Each tool is a small, single-purpose calculator that runs in your browser against the same climate record the rest of the site uses. None of them ask for an account, and none of them send your answers anywhere.

Heat & Safety

The heat here is a scheduling problem before it is anything else. These tools work out which hours are workable, how hot surfaces and cars actually get, and what to do when someone is in trouble.

Heat-Safe Hours Planner An hour-by-hour read on a typical day in any month, scored against what the activity can take. Which hours today are safe to be outside? Parked-Car Heat Timeline Interior temperature over the first hour, from published vehicle-heat studies, at Phoenix temperatures. How hot does a parked car get, and how fast? Pavement & Paw Check Five common surfaces by air temperature and sun, with the guidance that follows from each. Is the ground too hot for paws or bare feet? Heat-Illness Triage Guide A short decision path from symptoms to action, following CDC and county public health guidance. What do these symptoms mean, and what do I do now? Outdoor Event Heat Check The historical odds for any day of the year, above a threshold you choose. How often has it been this hot on my date? Trail Season & Rules Checker Preserve trails with their heat guidance, closures and official sources, each dated. Can I hike this trail today, and what are the rules?

Monsoon

Six weeks of the year deliver most of the Valley’s rain, most of its dust and nearly all of its flash floods. These tools track the season, prepare a household for it and walk through the decisions that matter when it arrives.

Monsoon Season Clock Days elapsed and remaining, the phase the season is in, and what the dew point is doing. Where are we in the monsoon season? Monsoon Prep Checklist Builder A checklist shaped to your home, car and pets, printable and exportable to a calendar. What should I actually do before the storms arrive? Dust-Storm Decision Flow Three situations, one decision path each, following ADOT guidance for dust storms. A wall of dust is coming. What do I do? Wash-Crossing Decision Flow A decision path for a flooded crossing, with the county guidance and the law behind it. The road ahead is under water. What now? Rain Log A month-by-month rainfall journal for your own address, compared with the Phoenix normals. How does my rainfall compare with normal?

Yard & Garden

Two growing seasons, a winter that never quite freezes and a summer that does. These tools answer what to plant, when to plant it and how much water it will take.

Desert Plant Picker A curated desert plant list you can filter by sun, water, size, pet safety and bloom. What should I plant here, and will it survive? Planting Calendar The Valley’s two growing seasons, month by month, with what to sow and what to pick. What can I plant this month? Citrus Care Calendar Twelve months of watering, feeding, pruning and freeze protection for Valley citrus. What does my citrus need this month? Frost & Freeze Date Explorer How often the Valley actually freezes, by month, and what each threshold does to a plant. Will it freeze, and when? Hydrozone Yard Planner Drop plants into water-use zones and see what the grouping means for the irrigation clock. Which plants belong on the same irrigation line? Sun Path & Shade Finder Sun altitude and bearing through the day, with the afternoon wall the sun lands on. Where will the shade fall, and when?

Home & Pool

Cooling equipment here runs harder for longer than almost anywhere in the country, and a pool in August is a different problem from a pool in January. These tools put both on a calendar.

Home Cooling Task Scheduler Filter, coil, pad and service dates for the equipment that carries a Phoenix summer. What does the cooling system need, and when? Pool Month-by-Month Planner Twelve months of pool care, with the water-temperature context that drives each task. What does the pool need this month? Peak-Hours Habit Planner Your daily routine against typical peak windows, with the habits worth moving. Which of my habits land in the expensive hours?

From the almanac

Long reads

Home, Pool & EnergyA cooling system maintenance calendarWhat a Phoenix cooling system needs across the year, ordered by what the equipment is actually doing in each month, a checklist drawn from the heat record.11 min readPublished 9 Nov 2026 Yard & GardenChoosing plants for a Phoenix yardHow to choose plants for a Phoenix yard from the four things the climate asks of them, with a comparison of the plant categories the local lists are built from.9 min readPublished 8 Nov 2026 Yard & GardenCitrus in the low desert, month by monthA Valley citrus tree keeps a calendar of its own: heavy water through the heat, feeding in spring and autumn, and the December nights that decide whether the crop survives.11 min readPublished 7 Nov 2026

How we work

Method

One place, one record

Every climate figure on this site comes from the 1991–2020 NOAA normals for Phoenix Sky Harbor International Airport, station USW00023183. Not a nearby city, not a regional average, not a figure copied from another site.

Dated, and checkable

Each dataset records its value, the source it came from, a link to that source and the date it was checked. Tool pages print the check date. Anything still unverified is marked as such rather than filled in.

Averages are not a forecast

A normal describes what a day in this month usually looks like. It cannot tell you what tomorrow will do. Every tool says so in its limits section, and none of them pretend otherwise.

No invented authority

The byline on these pages does not claim decades in the desert, and there are no testimonials and no user counts. This is an editorial project compiling public records, and it says that plainly.

Every source, listed

Before you start

Questions

What area does this cover?

Metro Phoenix and Maricopa County: the lower Sonoran Desert, roughly 1,100 feet above sea level. The climate figures come from Phoenix Sky Harbor International Airport. If you are in Tucson, Flagstaff or Yuma, the shape of the year is similar but the numbers are not, and the site does not pretend to cover them.

Is the heat index used here the official one?

Yes. Heat index values are computed with the Rothfusz regression and the two standard adjustments that the National Weather Service uses, from the hourly normal temperature and dew point. The category names (Caution, Extreme Caution, Danger, Extreme Danger) are the NWS categories at the NWS thresholds. What this site adds, and labels as its own, is the ceiling it sets for each kind of activity.

Why does everything use MST all year?

Arizona does not observe daylight saving time. The clocks here stay on Mountain Standard Time for all twelve months, so every hour, sunrise and sunset on this site is in MST with no seasonal shift. A tool that quietly applied daylight saving would put the hottest hour an hour out for half the year.

Can I use this to decide whether it is safe to work outside today?

No, and you should not. Every figure here is a long-term normal, not a forecast. For today, check the National Weather Service forecast for Phoenix and any heat advisory, warning or excessive heat warning in force. The tools are for planning a season, not for judging an afternoon.

Start with the heat-safe hours

The single most useful thing on this site is knowing which hours of a Phoenix day you can work in. It is ten seconds of clicking, and it changes how you plan a summer.

Open the planner