Weather in Phoenix

On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are April, May, and October. Phoenix is in United States at 33.4°N. The 2001–2020 NASA POWER daily record describes a humid subtropical climate.

July is the warmest month (average 33.9°C, high 40.8°C) and December is the coolest (average 11.9°C, low 5.2°C). Rain is about 256 mm of rain spread through the year. The wettest month is August at 34 mm; the driest is June at 2 mm.

When Phoenix gets wet

Annual rainfall is 256 mm. August leads at 34 mm; June is lightest at 2 mm.

Humidity peaks near 46%. That usually lines up with the wetter months rather than the hottest ones.

How warm Phoenix gets

Monthly average highs run from 18.6°C in December to 40.8°C in July. Nights follow the same curve: 5.2°C in December and 27.0°C in July.

Across the year the mean afternoon high is 30.1°C. If you want the smallest day–night shock, look at months where the high and low sit close together; July nights still hold 27.0°C.

The calendar in Phoenix

In February, Phoenix averages 20.6°C by day and 6.3°C at night, with 32 mm of rain. March: 25.0°C high, 9.2°C low, 21 mm rain, 38% humidity. April stands apart from the months beside it: 29.0°C / 12.3°C and 8 mm. May brings 6 mm and 1 rainy days; temperatures run from 17.2°C to 34.3°C. June is the driest month, averaging only 2 mm across 0 rainy days. Highs sit near 40.5°C. Peak heat arrives in July: 40.8°C by day, 27.0°C at night, and 30% humidity.

August is the wettest month — 34 mm and 8 rainy days, with 35% humidity. September brings 22 mm and 4 rainy days; temperatures run from 23.0°C to 37.5°C. October: 31.4°C high, 16.4°C low, 14 mm rain, 30% humidity. In November, Phoenix averages 24.8°C by day and 10.6°C at night, with 19 mm of rain. The year bottoms out in December. Plan for 5.2°C at night and 18.6°C in the afternoon.

When the score favours a visit

The three months with the highest comfort score are April, May, and October: April (20.7°C average, 8 mm, 29% humidity); May (25.8°C average, 6 mm, 22% humidity); October (23.9°C average, 14 mm, 30% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you prefer the hottest stretch, that is July. The coolest stretch is December.

Phoenix and other cities in United States

San Diego is about 481 km away: Phoenix is 9.9°C warmer than San Diego in its hottest month and a similar annual rainfall (269 mm in San Diego). San Diego’s wettest month is February (55 mm) versus August here.

Los Angeles is about 574 km away: Phoenix is 9.4°C warmer than Los Angeles in its hottest month and 75 mm drier over the year than Los Angeles. Los Angeles’s wettest month is February (75 mm) versus August here.

San Antonio is about 1363 km away: Phoenix is 3.9°C warmer than San Antonio in its hottest month and 523 mm drier over the year than San Antonio. San Antonio’s wettest month is May (100 mm) versus August here.