The climate of Arizona
Arizona has a primarily semi-arid to arid climate (Köppen climate classification BS, BW) at lower elevations, with pockets of continental (Köppen Dfb) and alpine (Köppen Dfc) types in the northern highlands. It is one of the Mountain states, which lies in the southwestern region of the United States. California and Nevada in the west, Utah in the north, Colorado in the northeast, New Mexico in the east, and the Mexican states of Sonora and Baja California in the south share borders with the state. The southern and western parts of Arizona are mostly arid lands, while the high altitudes in the north and east have alpine climates.
Arizona, the Grand Canyon State, has an average elevation of 1250 meters above sea level. Humphreys Peak has the highest elevation of 3852 meters in the state, while the Colorado River on the Sonoran border has the lowest elevation of 22 meters. Vast deserts, rosy mesas, high plateaus, numerous canyons and valleys, forests, and snow-capped peaks constitute the varied topography. The northeast has high plateau regions, while forests of Douglas fir, spruce, and pine are abundant in the north. A mountainous belt extends from the southeast to the northwest, with maximum elevations between 2727 and 3636 meters. The southwest consists of desert valleys and low mountain ranges. Arizona forms the Four Corners region with Utah, Colorado, and New Mexico.
Summers are exceptionally hot and dry in Arizona, with temperatures usually in the 90°F (32.2°C) to 120°F (48.9°C) zone. The southern desert occasionally registers temperatures above 125°F (51.7°C), while the average high temperatures reach a peak of 97°F (36.1°C) in July. Localized climate conditions exist due to the large area and variations in elevation in the state. The variations between day and night can range from 50°F (10°C) to 60°F (15.6°C) in the summer. Winter nights occasionally drop below freezing even when the average highs of the day touch 70°F (21.1°C). Although the days are warm in the cold season, cold air masses may push the temperatures below 0°F (-17.8°C) in the northwest. Spring and autumn have mild weather and generally comfortable conditions.
Arizona receives an average of 13" (330.2mm) of scanty rainfall in the year, with a peak during late summer. The mountainous region receives above 20" (508mm), while the southern desert sees extended periods of little to no precipitation. Arizona receives an average of 3500 hours of annual sunshine. Yuma has the highest number of sunny days and Flagstaff, the lowest among major cities. Snow accumulation reaches up to 100" (2540mm) in the high mountains of the north. The southern region barely receives snowfall. The average relative humidity remains low in the 30% to 50% range over the year. The growing season length varies from less than three freeze-free months in the northwestern mountains to several years without a freeze in the lower valleys.
Lake Havasu City recorded the highest temperature of 128°F (53.3°C) on June 29, 1994, in Arizona, while Hawley Lake recorded the coldest temperature of -40°F (-40°C) on January 7, 1971.
The best time to visit Arizona
The best time to visit Arizona is in the autumn season from September to November when the temperatures scale down from the peak of summer. Day highs are in the comfortable 65°F (18.3°C) to 85°F (29.4°C) range, and the nights fare even better. The humidity is low, and the mostly clear skies offer fantastic opportunities for stargazing. The fall season has fewer incidences of thunderstorms and tornadoes and is the time of festivals. Summer is scorching in Arizona, and temperatures often cross 110°F (43.3°C). Comparatively, fall sees refreshing conditions across the state.
The worst time to visit Arizona
The worst time to visit Arizona is during the harsh summer from June to August when the temperatures reach record highs of the year. Heatwaves often sweep the southern regions from the Sonoran desert. The difference between day and night temperatures is extreme and causes discomfort to people foreign to the conditions. Additionally, storms, including tornadoes, occur mostly in the summer, and there is a threat of lightning strikes and flash floods. Winter days are mild, with extreme temperature variations between day and night. Snowfall can throw a spanner in vacation plans.
Arizona is vulnerable to thunderstorms, floods, and tornadoes in spring and summer, and snowstorms in the winter. Thunderstorms are frequent in July and August and cause floods that inflict considerable local damage. High winds can reach speeds of 100 miles per hour during severe storms. Storms result in flash floods as the sparse vegetation, and uneven terrain has limited ability to hold water. Dry arroyos spill over the banks to halt traffic for many hours. The thawing of snow in the spring season and occasionally heavy rainfall floods rivers. Tornadoes are sporadic from May to August and average four in a year.
Weather in January
January is the coldest month of the year in Arizona, with wide variations in temperatures across the state. Nights are below freezing in the northern and central parts but are mild in the south and west. Flagstaff in the north receives more than 60" (1524mm) of snow and is a popular skiing destination, while Williams and Grand Canyon Village also account for sizeable snowfall.
Phoenix, the capital, rarely receives snow or ice and has comfortable temperatures between 46°F (7.8°C) to 69°F (20.6°C). The winter has plenty to offer as average temperatures vary from 17°F (-8.3°C) to 70°F (21.1°C), between night and day, and north and south. January is the snowiest month of the year, with the snowfall mainly concentrated in the northern and central regions.
Arizona is one of the rare places where the winter is attractive to snow lovers as well as those who prefer the moderate warmth of the sun. The cold days of January see 8 to 9 hours of sunshine in Arizona.
Weather in February
February lies in the short winter season of Arizona, with delightful day temperatures between 55°F (12.8°C) to 73°F (22.8°C). Freezing nights are prominent in the northern hilly areas, which also account for the maximum portion of the snowfall in the state. Frosty nights are common in the central and western regions, while the south rarely receives any snow.
The skies are mostly clear, and the light precipitation hardly registers in the 1" (25.4mm) to 2" (50.8mm) zone. Day trips to Petrified Forest and Painted Desert National Parks draw large tourist numbers with the temperatures in the warm 53°F (11.7°C) to 58°F (14.4°C) zone.
The Southern Rim of the Grand Canyon is open during the winter and is one of the famous tourist spots. Sleigh rides find many takers in the warm sunlight of February. Strong winds face little resistance due to the lack of natural barriers. The significant and quick drop in temperatures after sunset often catches tourists by surprise in February in Arizona.
Weather in March
March welcomes the spring season to Arizona with warm days and ample sunshine. The landscape remains mostly dry due to the shortage of rainfall. Temperatures range widely from 50°F (10°C) in the north to 80°F (26.7°C) in the west during the day. Northern Arizona has mostly freezing nights, but the conditions are warm in the rest of the state. Yuma in the west has warm temperatures in the 54°F (12.2°C) to 81°F (27.2°C), while Tombstone in the south is mild between 41°F (5°C) to 69°F (20.6°C).
March brings a combination of snow and cold nights, with warm days that witness a range of activities from cross-country skiing to mountain biking and camping. The lower desert areas do not receive snow and see a rapid increase in temperatures. Spring offers ideal conditions for fishing in the lakes and creeks, and canoeing in the deep canyons. Woodlands witness blooming flowers, and the landscape looks beautiful with a full range of wildflowers. Days warm rapidly but pack a warm coat for the cold March nights in Arizona.
Weather in April
April is a beautiful spring month in Arizona with brilliant sunshine and clear skies. The snow melts rapidly on the mountain slopes with at least 23 sunny days in the month. Snowfall is absent except in the alpine zone of the high mountains. The growing season is in full swing in the majority of the state.
The average high temperatures are between 58°F (14.4°C) to 89°F (31.7°C), while the average night temperatures register in the freezing 29°F (-1.7°C) to mild 60°F (15.6°C) range. April is mostly dry, but the low humidity keeps the conditions comfortable in the majority of the state.
Biking and hiking are popular, while there is an abundant supply of Apache trout in the rivers and streams for fishing enthusiasts. The mountain scenery is enjoyable during spring, and there is a chance to spot a mountain lion in the wild. Carry at least a sweater for comfort during the nights on camping trips. A warm jacket suits best for cold evenings in April in Arizona.
Weather in May
May is sunny in Arizona with long daylight hours and mild, comfortable nights. The average high temperatures reach up to 98°F (36.7°C) in the west in places like Bulkhead City, Parker, and Yuma. Phoenix records average temperatures between 69°F (20.6°C) to 95°F (35°C), while Tucson in the south is between 64°F (17.8°C) to 91°F (32.8°C). Nights vary between 35°F (1.7°C) to 70°F (21.1°C), with the northern areas occasionally on the verge of freezing.
The sun stays on the horizon for at least 8 hours a day, yet evenings see a rapid cool down under the influence of the clear skies. The smell of the blooming flowers draws the attention of swallowtails in the gardens and particularly, in the wild. National parks and forests see a rise in tourist footfall in the comfortable spring weather. The northern portion is home to pine forests, which have lower temperatures than the southern desert lands and attract considerable interest from visitors. Expect the temperatures to increase gradually with each passing day in May in Arizona.
Weather in June
June begins the hot summer season in Arizona, with the longest days of the year amid bright sunshine. The average high temperatures are in the hot zone of 81°F (27.2°C) to 108°F (42.2°C), while the average low temperatures are way down in the 42°F (5.6°C) to 77°F (25°C) range. Extreme temperature variations occur between day and night in different parts of the state that is uncomfortable for tourists.
Occasional thunderstorms and tornadoes make their way to the interior lands. Hiking and biking trails extend from the heart of the cities to the mountains. The best time to go for a swim in a pool is in the morning when the sunshine is still bearable. Leave the afternoons for relaxing at the resort while enjoying a spa. The mountains offer lower temperatures than the desert lands but avoid afternoon hikes as far as possible beneath the scorching sun. The heat is mostly of the dry type, with the humidity in the low range of 30% to 50%. June is prone to thunderstorms in Arizona.
Weather in July
July is generally the peak of the summer in Arizona, with the average high temperatures in the astonishingly high range of 81°F (27.2°C) to 112°F (44.4°C). Nights vary from a cool 51°F (10.6°C) in the Grand Canyon Village in the north to warm 85°F (29.4°C) in Lake Havasu City in the west.
Precipitation reaches up to 4" (101.6mm) in Bisbee, Green Valley, and Coronado National Monument in the south, with frequent thunderstorms that bring the majority of the rainfall. Temperatures reach above 120°F (48.9°C) in the southern desert region, with 11 hours of intense sunshine in Yuma.
Sunscreen is mandatory during most of the day, but it is prudent to avoid outdoor excursions, especially in desert areas where water availability is questionable. Light summer clothing is the best wear, but be sure to carry broad-brimmed hats and sunglasses when out in the open. Severe thunderstorms bring heavy rainfall and flash floods without giving much time to get out of their way. Watch out for thunderstorms during the afternoons in Arizona in July.
Weather in August
August is hot in the summer season of Arizona, with average high temperatures in the 78°F (25.6°C) to 110°F (43.3°C). Flagstaff in the north averages between 50°F (10°C) to 78°F (25.6°C), while Sedona in the center is between 66°F (18.9°C) to 94°F (34.4°C). The Phoenix Area is warm in August and registers between 75°F (23.9°C) to 104°F (40°C).
Rainfall averages from 2" (50.8mm) to 4" (101.6mm) in the south and central regions, while it is light elsewhere. Backcountry camping provides a unique challenge to adventurers in summer. The Grand Canyon National Park finds many takers during summer vacations and is abuzz with activities like canoeing and kayaking the rapid waters. Wild animals usually avoid the hot sun and forage for food at dawn and dusk. Fishing is popular during the summer, with an increase in the water levels due to the moderate amount of precipitation. Heavy rainfall floods dry arroyos and stalls vehicular movement. Expect the temperatures to cool down by the end of August in Arizona slightly.
Weather in September
September welcomes the beautiful autumn season with comfortable weather in Arizona. The average high temperatures are in the warm range of 73°F (22.8°C) to 100°F (37.8°C), while the nights are temperate in the average low temperature zone of 42°F (5.6°C) to 76°F (24.4°C).
Moisture from the Gulf of California occasionally reaches the interior of Arizona to bring moderate rainfall in the range of 1" (25.4mm) to 2" (50.8mm) in the north and the south. The skies remain clear, with at least 25 sunny days amid a low degree of humidity. The early fall season sees a significant drop in temperatures and thunderstorms compared to the summer.
Wildlife is active during dawn and dusk when the conditions are comfortable to forage for food. Many tourists prefer to visit the national parks and forests during the fall season due to moderate conditions. The northern hilly areas are a favorite destination for many with cooler temperatures and are the first places in the state that see leaves changing colors in fall. The hunting season is in full swing in September in Arizona.
Weather in October
October is one of the best times to visit Arizona, with pleasant temperatures and beautiful colors in the fall season. The daily sunshine lasts for 9 to 10 hours but is moderately intense compared to the peak of summer. The average high temperatures are in the comfortable 62°F (16.7°C) to 90°F (32.2°C) range, while the average low temperatures are in the wide range of 32°F (0°C) to 62°F (16.7°C). Prescott, Payton, and Painted Desert National Park in the central portion register comfortable temperatures between 40°F (4.4°C) to 73°F (22.8°C).
The peak foliage occurs in the third to fourth week of October in the majority of the state. The northern hilly areas witness color changes earlier than the southern part, which sees peak hues by November. The aspens turn yellow on the Inner Bain Trail in Flagstaff, while maples show brilliant hues in the Pinetop-Lakeside area along the Mogollon Rim by early November. Light sweaters provide comfort in the breezy evenings of October in Arizona.
Weather in November
November ends the mild autumn season in Arizona, with temperatures in the average range of 32°F (0°C) to 90°F (32.2°C). Canyon de Chelly, Page, and Pipe Springs Monument in the north average between 38°F (3.3°C) to 72°F (22.2°C), while Sierra Vista, Tombstone, and Tucson in the south register between 51°F (10.6°C) to 84°F (28.9°C).
Rainfall is scanty throughout the state and rarely exceeds 1" (25.4mm) to 1.5" (38.1mm). November has calm weather, with clear skies that are perfect for stargazing. Nights see a significant drop in temperatures in the northern forests and hills. The Santa Catalina Mountains appear straight out of a book with the snow-capped mountains in the background amid colorful trees in the front.
Fall is an ideal time to meander on the nature trails and take a scenic drive along the mountain slopes and countryside with the wind in the face. Ski enthusiasts eagerly wait for the accumulation of snow. In the hilly north of Arizona, the snowfall begins by late November.
Weather in December
December begins the winter season in Arizona with warm days and cold nights. The skies are mostly clear, with little precipitation in the majority of the state. Temperature differences are extreme between day and night due to the arid nature of the land. The high desert areas are prone to cold conditions during the night. Grand Canyon Village in the north registers cold temperatures between 18°F (-7.8°C) to 45°F (7.2°C). The average high temperatures are in the mild 41°F (5°C) to 68°F (20°C) range, while the average low temperatures are in cold 17°F (-8.3°C) to 41°F (5°C). [Resources]
Southern Arizona rarely receives light snowfall, while the northern mountainous areas receive ample snow. The warm and dry conditions attract tourists in the winter who wish to escape from the deadly cold in the northern United States. The days do not require warm clothing, but the nights ask for them. A trip to the snow-clad mountains witnesses a winter wonderland in the making. December brings a merry Christmas in Arizona.