Climate and monthly weather forecast
Arizona, USA

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.

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 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.

Spring in Arizona is characterized by milder weather and more agreeable conditions. During this season, the state transitions from its cooler winter days, with average daytime temperatures gradually rising. However, variations in temperature between day and night remain, sometimes ranging from 50°F (10°C) to 60°F (15.6°C). Precipitation is relatively limited during spring, but the overall ambiance is comfortable, making it a popular season for many visitors.

Summer in Arizona is known for its scorching heat. This season sees temperatures regularly between 90°F (32.2°C) and 120°F (48.9°C). The southern desert areas can become extremely hot, at times recording temperatures even above 125°F (51.7°C). Despite the intense heat during the day, the temperature difference between day and night remains vast, often ranging from 50°F (10°C) to 60°F (15.6°C). Rainfall is scarce, but when it does occur, it's typically in the form of intense thunderstorms.

Autumn brings relief to Arizona after the harsh summer months. The temperatures during this season are more moderate, fluctuating between 65°F (18.3°C) and 85°F (29.4°C). Rainfall is still limited, but the skies are mostly clear, creating ideal conditions for outdoor activities and stargazing. Moreover, the reduced humidity and absence of severe weather events make it one of the most pleasant periods in the state.

Winter in Arizona is varied, with some regions experiencing mild days and others facing the cold intensely. Daytime temperatures can touch 70°F (21.1°C), but the nights are much colder, sometimes falling below freezing. The northwestern parts of the state can even see temperatures plummet below 0°F (-17.8°C) during particularly cold spells. Snowfall is prevalent in the northern high mountains, accumulating up to 100" (2540mm), while the southern regions rarely witness any snow.

January is one of the chillier months in Arizona, setting the tone for the state's winter. The climate can vary greatly depending on the region. In the southern desert areas, daytime temperatures are relatively mild, hovering between 65°F (18.3°C) and 75°F (23.9°C). Weather in January »

February continues the winter season in Arizona, but there are subtle hints of an approaching spring. This month experiences a slight increase in temperatures compared to January, yet the variations across the state remain noticeable. In the southern desert regions, encompassing cities like Phoenix, daytime temperatures usually lie between 68°F (20°C) and 78°F (25.6°C). Weather in February »

March in Arizona ushers in distinct signs of spring, with warmer days becoming more prevalent. The disparity in temperatures between the state's regions remains, but overall, there's a palpable increase from the colder months of January and February. The southern desert areas, which include cities such as Phoenix, see daytime temperatures ranging from 75°F (23.9°C) to 85°F (29.4°C). Weather in March »

April is a quintessential spring month in Arizona, marked by steadily increasing temperatures and a clear departure from the chill of winter. The landscape begins to bloom, providing a picturesque backdrop for residents and tourists alike. Phoenix and the encompassing southern desert regions experience daytime temperatures that fluctuate between 80°F (26.7°C) and 90°F (32.2°C). Weather in April »

May signifies the advent of Arizona's transition from the mild spring season to the upcoming intense heat of summer. This month exhibits a noticeable escalation in temperatures throughout the state, laying the foundation for the hot days ahead. In the southern desert locales, including Phoenix, daytime temperatures predominantly lie between 90°F (32.2°C) and 100°F (37.8°C). Weather in May »

June in Arizona is emblematic of the full-throttle summer season, with temperatures soaring across the state. The heat becomes pervasive, making this month one of the hottest periods in Arizona. Phoenix and surrounding southern desert areas experience some of the highest temperatures of the year during June. Weather in June »

July in Arizona can be described as the epicenter of the summer heat, with temperatures often reaching their peak values for the year. However, this month also introduces the monsoon season, bringing sporadic rain showers and thunderstorms to parts of the state. Phoenix, along with other southern desert areas, grapples with blistering heat in July. Weather in July »

August in Arizona continues to ride the wave of sweltering summer temperatures, but it is also characterized by increased monsoonal activity, bringing bouts of rain, thunderstorms, and occasionally, flash floods to various parts of the state. The southern desert regions, including places like Phoenix, remain enveloped in high temperatures during August. Weather in August »

September in Arizona heralds the beginning of a shift from the stifling summer heat towards the more temperate conditions of autumn. The month is marked by a steady decline in temperatures, making it progressively more comfortable, especially in the latter half. The southern desert expanses, such as Phoenix, start to experience some relief from the relentless summer heat. Weather in September »

October in Arizona marks the heart of the autumn season, with temperatures continuing their downward trajectory from the summer peaks. The month is characterized by mild days and cooler nights, offering a pleasant contrast to the hotter months preceding it. Phoenix and the southern desert regions witness a notable decline in temperatures, making outdoor activities more enjoyable. Weather in October »

November in Arizona signifies the deeper embrace of autumn, especially in the northern regions, while in some areas, hints of the forthcoming winter start to make an appearance. The month is characterized by further cooling temperatures, shifting landscapes, and increasingly crisp nights. In the southern desert territories like Phoenix, the drop in temperatures continues. Weather in November »

December in Arizona is a month of contrasts, where the south remains relatively mild while the northern areas feel the winter's cold grip. The month ushers in the colder season, and with it comes a range of weather experiences depending on the region. The southern desert areas, including cities like Phoenix, maintain a mild climate even in December. Weather in December »