Climate of Phoenix

Desert Botanical Gardens

Phoenix, which only averages four days with measurable rain during each of the months of December, January and February, sees rainy days drop off to three in an average March, two in April and only one in May and June. July and August with an average of five rainy days each can be termed the second "rainy season" of the year. September normally sees only three days with rainfall while the warm quiet days of October and November are broken by only two days with rainfall, based on records that extend back for sixty years. One must remember that Phoenix and the Valley of the Sun is situated in one of the driest regions of the North American continent. Even though rains occur on an average of one to five days per month as outlined, we must remember that the total rainfall is indeed small when compared with other regions of the continent. With an annual average of only 7.16 inches we find that only three months of a normal year find totals close to the one inch mark-December 0.97 inch, August 0.99 and September 1.00 inch are the months with largest rainfall totals. From these high points we find the "dry season" April, May and June running 0.35 inch for April, 0.17 for May and the lowest of low points . . . only 0.06 inch for the entire month of an average June (which we recall has only one cloudy day with rain!). The "golden" months of October and November when the valley shakes off the lethargy of the hot summer, sees rainfall of 0.40 inch for October and 0.47 for November. These are the months when cottonwood and sycamore trees along canal banks and city streets take on their golden hues as afternoon temperatures average close to 88 degrees in October and 76 in November.

Phoenix is sheltered from heavy winter storms by the high coastal mountains of California and Lower California. The intense storms that lash the west coast with gales and driving rains spend much of their energies on the steep ramparts of the Cascades and Sierra Nevada Mountains where snows often reach depths of 200 to 400 inches in a season. As these eastward moving low pressure areas continue their journey toward the Continental Divide, Phoenix and the Valley of the Sun experience the few cloudy and rainy days of the winter season that I mentioned earlier. The "high country" though, about 100 to 200 miles to the north and east of Phoenix, receives substantial snows which provide the life-giving waters that refresh the wide checkerboard farmlands of the Valley. Through hundreds of miles of canals and ditches, water comes to the "desert" from precious reserves in mountain reservoirs that are replenished by these winter storms.

Encanto Park A Sunday in the desert

From March through June it is a rare day, indeed, that brings stormy weather to Phoenix. Late in June or early in July the first thunderheads begin to arrive with air that has journied from the Gulf of Mexico across the rugged mountains of northern Mexico into the Valley. White turrets reach into the blue skies over the Superstition Mountains on the east side of the valley and over the Bradshaws which form the northern ramparts of the valley. Thus, the summer "rainy" period is heralded. On still, hot days of July, when temperatures soar to 105 degrees, eyes are raised to the towering thunderheads visible over surrounding mountains almost every day. Grateful hearts give thanks to God for the beautiful displays of lightning, interspersed with the deep rumble of thunder, and the welcome cooling rains that refresh the land and give promise of renewed life. July in Phoenix experiences seven thunderstorms normally with a peak of eight during an average August and four during September. All other months of the year experience one or less thunderstorms. Humidities during July and August rise slightly as the air from the Gulf of Mexico makes its appearance. However by September westerly winds again bring bracing dry air which characterizes the Arizona desert during ten months of an average year. June sees lowest humidities with averages during the month at 5:30 p.m. standing at only 14 percent! Even in December and the months of January and February we find that average late afternoon humidities rarely rise above 35 to 40 percent.

Horsethief Basin Resort winter

On rare occasions, cold fronts associated with storm systems passing north of Arizona sweep deep into the Southwest bringing with them brief periods of dusty windy weather which culminates in brief showers that wash the air and bring the deep blue color back into Arizona skies again. Summer thunderstorms also bring with them brief bursts of high wind and dust just before rains commence. This dust normally lasts only about five or ten minutes and is soon laid low by the welcome shower that follows. Wind speeds in the valley average five miles per hour. They range from a high mean hourly speed of 5.8 in May and July down to 4.0 miles per hour in December.

Often one hears the comment that so much irrigated farm land around the city of Phoenix must result in increased humidity values. A check of average relative humidity values comparing Las Vegas, Nevada, Tucson and Phoenix against increased irrigated lands in the Phoenix area produced no evidence that irrigation has in any way affected the relative humidity in the Valley of the Sun. The average daytime relative humidity is 29 percent based on observations taken at 11:30 a.m. and at 5:30 p.m. Thus we see unfolded a climate in the desert land of Arizona that rivals climates half way around the world. Hotter than the desert at Khartoun in the Egyptian Sudan where July average daily temperatures stand at 89.6 degrees while Phoenix swelters with 90.1 degrees. (But with much more refrigeration! Offices, stores and residences-rare indeed is a building in Phoenix that does not have cooling devices of some type which counteract the outdoor heat.) Like all desert climates, Phoenix experiences high temperatures during late spring and summer. May marks the first month with maximum temperatures over the century mark-an average May sees four days with temperatures of 100 degrees or higher with the normal daily high standing at 93.5 degrees. June normally sees more high temperatures in the Arizona capitol city than any other month of the year. An average of 25 days of the month of June are 100 degrees or warmer while 15 of those days experience readings of 105 degrees or above. Nighttime temperatures remain cool during June, averaging 66 degrees as compared with the average daily maximum temperature of 102 degrees. Relative humidity values are extremely low during May and June, averaging only 15% at 5:30 in the evening. Thus evaporative coolers function very efficiently during this part of the summer.

July and August do not see extreme temperatures quite as high as June (record all-time high 118 degrees on June 24, 1929), but warmer nights, due to increased humidity and cloudiness, bring normal daily temperatures to their highest values of the year. July sees an average daily high temperature of 105 degrees with normal daily minimum values standing at 75. August is imperceptibly cooler-102 degrees for normal high temperatures and 74 for low values. Humidities are from 10 to 15% higher during these two months so that refrigeration proves to be the most efficient form of cooling during most of July and August.

The change from the long hot days of summer begins to appear during the latter part of September. Sudden changes in temperatures occur during this transition period which runs through October. Ordinarily we find that the greatest change in any month takes place in October. Between the beginning of the month which often has warm summery days and the end of October with cool bracing evenings and balmy afternoons, we see the complete transition from summer to the mild winter season. By November Phoenix and the Salt River Valley region is definitely a place where the sun spends the winter. The mild winter season continues into March. Warmer than Mexico City in November, Phoenix has a normal monthly average temperature of 58.4 as compared with 56.5 degrees in Mexico City. February's average temperature in Rome is 46.8 degrees while Phoenix can boast of a temperature of 54.3 degrees March brings Spring to the valley with its profusion of flowers, new leaves on trees, and all other manifestations of this glorious season. March weather in Phoenix can really be termed "Paris in the Spring" type of weather. An average temperature of 59.9 with only about one-third as much rain as Paris (Paris has 2.20 inches of rain in their "Spring" month of May which has an average temperature of 56.8 degrees).

April in the valley, with an average daily temperature of 67 degrees, is a delightful month. Cool evenings on the desert-a mesquite fire on which sizzling steaks are broiling, the fire throwing welcome heat on folks grouped around it-desert stars seem to be just out of arm's reach in the clear bracing air, tinged with indescribable odors of the Arizona desert. May begins to hold the promise of long hot days from June through August yet to come. Average high temperatures in May climb to 93.5 degrees but nights remain cool with minimum temperatures close to the 57 degree mark.

Thus, in Phoenix and the Salt River Valley we see unravelled with each month of the calendar a variety of weather, temperature and climate which is a composite of climates found in far corners of the world. And always, with unvarying regularity the sun beams down on this favored land. Even in December and January we find more than 75 percent of the possible sunshine in Phoenix.

Phoenix-Parks and Recreation

In Phoenix there's a man who spends a good part of his time moving holes.

There's also a man whose job it is to look after a place where nobody has lived for 700 years.

And there's a man who chops weeds under water.

These odds and ends of information all relate to an important function in Phoenix and, too, an important reason why life in Phoenix is pleasant, both for visitors and home folks. It's the city's Parks and Recreation Department (PARD for short).

Interested in knowing how those oddities tie in?

Well, the man who moves holes works at the Encanto municipal golf course. Periodically the cups (you know - the maddening little thingumbobs that the ball is supposed to roll into) get worn around the edges. So the man comes along and digs a new hole and puts the cup there and fills up the old one. Simple.

The man who looks after a place where nobody has lived for 700 years is the city archeologist, Odd S. Halseth by name. He presides over Pueblo Grande, an excavated Indian ruin occupied some seven centuries ago by a people known as the Hohokam. It's a very popular place, too. It was visited last year by 29,000 persons, none of them (so far as could be determined) descendants of the Hohokam.

Now, then, the man who chops weeds under water: He works out at the Encanto Park lagoon, which is where the weeds grow under water, on account of the warm weather. Canoers keep getting their paddles tangled in the stuff, and little boys lose their fish hooks in it. And so, every once in a while, the man rides over the lagoon in a funny-looking boat with mechanical blades, and chops out the weeds. Simple.

All these things, however, are only a small part of the parks-and-recreation story in Phoenix.

There are eleven well-distributed parks in the city plus 35 school playgrounds where PARD carries on supervised recreation programs. There are six swimming pools. There's an adult recreation center, which used to be the public library until a new one was built. Since nobody throws anything away in Phoenix, even old libraries, this one was converted into a haven for grown-ups, especially older and retired grown-ups, including winter visitors. They foregather there to rest, read, play cards or just sit and visit. And now and then they troop off behind an expert guide to picnic on the desert or tour points of interest hereabouts.

One of PARD's biggest responsibilities is looking after South Mountain Park, the largest municipal park in the world (14,817 acres of desert, mountains, cactus, picnic ramadas and unalloyed sunshine). Horsethief Basin is another of PARD'S special charges, which makes Phoenix probably the only city in the world that has a park 95 miles beyond and 5,000 feet above the city limits. It's a summer recreation area located in the Bradshaw Mountains, and it got its name from the fact that bad men used to rustle horses in the valley and then hide them out in the Basin. If it's archery you're interested in, you can sign up for archery classes at the parks and take part in bow-and-arrow tournaments. Crafts? Those, too. Clowning? Yup, even that. There's a new club for clowns past, present and would-be just organized by the parks department.

And, oh, yes, there's Pete the Pelican. He hangs out around the Encanto lagoon. You can see him any time, except when he's off tom-catting (or, rather, peli-catting) around the neighborhood. Jolts heck out of people when they open their door to get the morning paper and find a pelican on the front porch.