Phoenix records about 203mm of rain across roughly 33 wet days a year, which is a 9% chance on an average day. August is the wettest month at 32mm (16% of the annual total) and June the driest at 1mm. Local rain type: thunderstorms. Phoenix is extraordinarily dry most of the year. The summer monsoon season (July-September) brings dramatic but brief thunderstorms — watch from under cover.
Chance of rain on an average day: 9%
Rainfall climatology for Phoenix. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 203mm |
| Rain days per year | 33 |
| Odds on an average day | 9% |
| Wettest month | August — 32mm over 5 days |
| Driest month | June — 1mm over 1 days |
| Rain type | thunderstorms |
| Best dry window | October through May offers nearly rain-free conditions with comfortable winter temperatures. |
| Worst rain window | July and August bring monsoon thunderstorms with spectacular lightning — beautiful but occasionally dangerous. |
August delivers 3100% more rain than June (32mm vs 1mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 16% of the annual total, so rain in Phoenix is spread through the year — there is no season you can rely on being dry.
Phoenix rain arrives in short, heavy bursts — shelter and timing matter more than gear.
Rain falls on about 5 days in August against 1 in June — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 19mm | 3 | 10% | 20°C |
| February | 18mm | 3 | 10% | 20°C |
| March | 22mm | 4 | 13% | 23°C |
| April | 6mm | 1 | 3% | 28°C |
| May | 2mm | 1 | 3% | 33°C |
| June | 1mm | 1 | 3% | 38°C |
| July | 24mm | 4 | 13% | 41°C |
| August | 32mm | 5 | 17% | 41°C |
| September | 16mm | 3 | 10% | 38°C |
| October | 18mm | 3 | 10% | 33°C |
| November | 15mm | 3 | 10% | 28°C |
| December | 23mm | 4 | 13% | 23°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Phoenix we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Phoenix records rain on roughly 33 days a year — about a 9% chance on any given day — totalling around 203mm.
August, with about 32mm over 5 rain days. That is 16% of the entire year's rainfall in a single month.
June is the driest month at 1mm across roughly 1 days. October through May offers nearly rain-free conditions with comfortable winter temperatures.
Phoenix is extraordinarily dry most of the year. The summer monsoon season (July-September) brings dramatic but brief thunderstorms — watch from under cover.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.