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Phoenix weather by month: averages, rainfall & climate trends

The desert heart of the Sun Belt, Phoenix spreads across the Sonoran Desert beneath near-relentless sunshine: a city defined by its searing summers, saguaro-studded surroundings and the dramatic arrival of the summer monsoon. Phoenix weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

−1.1°Fhigh near average

87° / 68°Today
88° / 61°Average
see today in detail →

How it's changed

+4.4°Faverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–490frost days a year now (2016–2025) · 10 in the 1940sfrost days a year · 10 in the 1940s203days above 86°F a year now (2016–2025) · 178 in the 1940sdays above 86°F · 178 in the 1940s+4.4°F vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 1.3 incheshigh 66°low 42°February, rain 1.2 incheshigh 71°low 45°March, rain 1.1 incheshigh 77°low 50°April, rain 0.4 incheshigh 86°low 57°May, rain 0.1 incheshigh 95°low 66°June, rain 0.1 incheshigh 104°low 75°July, rain 0.7 incheshigh 107°low 83°August, rain 1.3 incheshigh 104°low 82°September, rain 1.1 incheshigh 100°low 75°October, rain 0.9 incheshigh 89°low 62°November, rain 0.8 incheshigh 76°low 50°December, rain 1.2 incheshigh 66°low 42°wettest month August, 1.3 inches · 10.1 inches a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Overcast

Right now

68.0°

63°feels like
33%humidity
38°dew point
4 mphfrom E
UV index0.0
sunrise06:35sunset17:51day length11h 16m
TodayOvercast87°68°
MonOvercast82°65°
TueOvercast88°79°
WedOvercast84°79°
ThuClear85°75°
FriClear81°73°
SatClear87°73°

On this date: October 18

Today (forecast)
87° / 68°
Average for October 18
88° / 61°

High near average · −1.1°F

  • Record high: 101.5° · 2003
  • Record low: 48.0° · 1966
  • One year ago: 84° / 58°

Every October 18 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 18 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Phoenix is sampled from the ECMWF ERA5 reanalysis at 33.45°N, 112.07°W, with daily records since 1940.

Coordinates
33.45°N, 112.07°W
Time zone
America/Phoenix
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

19 of the last 31 days were warmer than the historical average for that date. Average difference: +1.6°F.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

Phoenix lies in the north-eastern Sonoran Desert and has a hot desert climate (Köppen BWh), among the hottest of any major U.S. city. Its low desert elevation and extreme aridity produce long, blazing summers and abundant sunshine for most of the year. The main seasonal change is the North American monsoon, which arrives in mid-summer to interrupt the dry heat with bursts of thunderstorms.

Those monsoon storms carry their own hazards: flash flooding, damaging winds and towering dust storms, or haboobs. Phoenix's defining trend, though, is heat: recent summers have set records for extreme high temperatures, with 2023 and then 2024 each surpassing the previous year. Rapid urban growth has intensified the urban heat island, steadily lifting overnight low temperatures and limiting the desert's natural night-time cooling.

The warmest month is July, with typical afternoon highs of 106.8°F and nights around 83.2°F. On about 150 nights a year, the temperature never drops below 68°F. At the other extreme, January brings afternoon highs of about 66.3°F and typical overnight lows of 41.5°F.

The yearly total for Phoenix comes to about 10.1 inches; monthly amounts range from 0.1 inches in June up to 1.3 inches in August.

Over the full record (since 1940), the annual mean temperature in Phoenix has risen by 4.4°F between its first decade and its last. That last decade has also been the warmest in the record.

Sources:en.wikipedia.orgbritannica.comweather.gov

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 43°F. Wettest month: August (~1.3 in). Whole year averages ~10.1 inches of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 24 rainy days a year: most in January (~3), fewest in June (almost none).

Bars = average number of days with ≥ 0.08 in per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Phoenix month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January66.3°41.5°1.3 in310.0 h88.5° (1971)21.0° (1963)
February70.9°45.0°1.2 in310.8 h90.8° (1963)25.2° (1964)
March77.0°50.0°1.1 in311.8 h99.3° (2007)28.0° (1966)
April85.9°57.1°0.4 in112.8 h104.2° (2012)39.0° (1975)
May94.5°65.9°0.1 in013.7 h113.2° (1984)43.4° (1967)
June104.1°75.2°0.1 in014.2 h120.4° (1990)55.6° (1950)
July106.8°83.2°0.7 in214.0 h120.1° (1995)66.3° (1992)
August104.5°81.7°1.3 in313.2 h117.2° (2025)64.0° (1949)
September99.8°74.6°1.1 in212.2 h115.3° (1950)53.8° (1965)
October88.8°61.9°0.9 in211.1 h109.9° (2024)36.2° (1971)
November75.6°49.6°0.8 in210.2 h97.6° (2020)28.6° (1958)
December66.3°42.2°1.2 in39.8 h85.3° (1950)21.5° (1968)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +4.4°F.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.58°F per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Mar–May is warming fastest: +0.65°F per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 86°F per year: 178.4 early in the record → 202.6 recently. Frost days: 10 → 0.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 1990, all-time low in 1963: 120.4°F / 21.0°F.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~10.1 in/year on average. Last decade: −2% vs that average. Long-term trend: +0.16 in per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Phoenix

Which is the warmest month in Phoenix?
On long-term average, the warmest month in Phoenix is July (mean daily temperature of about 95.0°F) and the coolest is January (about 52.4°F).
How does today's temperature in Phoenix compare to the historical average?
On October 18, 2026, Phoenix is forecast to reach a high of 87.1°F and a low of 67.8°F. The long-term average for this date (the full record since 1940) is a high of 88.2°F and a low of 60.9°F, so today's high is 1.1°F cooler than that average.
How much has Phoenix warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Phoenix is about 4.4°F warmer.
How much does it rain in Phoenix?
Phoenix receives about 10.1 inches of precipitation per year on long-term average, with August typically the wettest month.
What is the average temperature in Phoenix?
Over the full record (since 1940), the annual mean temperature in Phoenix is about 73.3°F. The warmest month is July and the coolest is January.
What are the average temperatures in Phoenix by month?
Average daily highs and lows for each month in Phoenix (°F, full record since 1940): January 66°/42°, February 71°/45°, March 77°/50°, April 86°/57°, May 95°/66°, June 104°/75°, July 107°/83°, August 104°/82°, September 100°/75°, October 89°/62°, November 76°/50°, December 66°/42°.
What is the weather like in Phoenix in summer?
In summer, June through August, Phoenix is dry and really hot. Expect 104–107°F by day and 75–83°F at night, with July the warmest month. Rain picks up through the season, 0.1 inches in June to 1.3 inches in August.
What is the weather like in Phoenix in winter?
December to February is winter in Phoenix, and it is mild. Daytime highs sit at 66–71°F and nights at 42–45°F; January is the coldest month. Rain is steady at around 1.2 inches a month, spread over roughly 3 days. It is the wettest season of the year.
What is the weather like in Phoenix in spring?
In spring, March through May, Phoenix is dry and warm. March starts at 77°F by day and 50°F at night; by May it is 95°F and 66°F. Rain falls off from 1.1 inches in March to 0.1 inches in May. No season is drier.
What is the weather like in Phoenix in autumn?
September to November is autumn in Phoenix, and it is hot. It cools from 100°F by day and 75°F at night in September to 76°F and 50°F in November. Rain is steady at around 0.9 inches a month, spread over roughly 2 days.
How many days a year does it rain in Phoenix?
On long-term average, Phoenix has about 24 days a year with at least 0.08 inches of rain or snow. The annual total is roughly 10.1 inches.

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