Rainy Season in Arizona: Month by Month

Quick answer: Arizona’s monsoon season runs from June 15 to September 30 — that is the National Weather Service’s own calendar for it — but the rain itself arrives in July: Tucson’s wet months are Jul–Sep, with 92 mm (3.6 in) in July against 12 mm (0.5 in) in June. Phoenix has a second, winter rainy season as well: its wet months are Jul–Sep, Dec–Mar.

Pick a destination to see its weather month by month and the best time to go, or pick a month to see where the weather is at its best.

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Destination

Best = an ideal daily high for the kind of trip and rain on 10 days or fewer; the rule is under the tool.

Tokyo · a city trip

Good: Mar–May, Oct–DecNo month is ideal for a city trip by our rule, but these come close.

Warmest: Aug · 89°F
Coolest: Jan · 49°F
Wettest: Jul · 16 rain days

Averages for 2006–2025: any single year can be hotter, colder or wetter.

Weather from NASA POWER daily data, 2006–2025, for the ~50 km area around each place. Right on the coast, afternoons can be a few degrees warmer than shown.

Month	High / low (°F)	Rain days	Rain (in)	Verdict
Jan	49° / 34°	5	2.4	Off (too cold)
Feb	51° / 35°	7	3.1	Off (too cold)
Mar	57° / 40°	12	5.1	Good (cool, showery)
Apr	65° / 48°	12	6	Good (showery)
May	73° / 58°	13	6.6	Good (showery)
Jun	79° / 65°	16	8.1	Off (too wet)
Jul	86° / 73°	16	6.5	Off (too wet)
Aug	89° / 75°	15	5.4	Off (too hot)
Sep	82° / 70°	16	8.7	Off (too wet)
Oct	72° / 59°	14	8.9	Good (showery)
Nov	63° / 48°	11	4.4	Good (showery)
Dec	54° / 39°	7	3.2	Good (cool)

The tool above opens on Phoenix: change the place or the month to yours, or compare Tucson and Sedona. Below, Arizona month by month — rain, rain days and how warm it is.

Arizona month by month

Average rainfall and the number of days with at least 1 mm of rain, 2006–2025. On this page a month counts as wet when it gets more rain than an average month in that place (more than a twelfth of its year), and dry when it gets less than half an average month. The months in between are the shoulder.

Month	Phoenix	Tucson	Sedona	Phoenix: rain
January	4 days — wet	4 days — shoulder	6 days — wet	32 mm (1.3 in)
February	3 days — wet	3 days — shoulder	5 days — wet	24 mm (0.9 in)
March	3 days — wet	3 days — dry	6 days — wet	24 mm (0.9 in)
April	1 days — dry	1 days — dry	3 days — dry	5 mm (0.2 in)
May	1 days — dry	1 days — dry	3 days — dry	6 mm (0.2 in)
June	1 days — dry	3 days — dry	2 days — dry	4 mm (0.2 in)
July	9 days — wet	18 days — wet	15 days — wet	37 mm (1.5 in)
August	9 days — wet	16 days — wet	14 days — wet	37 mm (1.5 in)
September	5 days — wet	9 days — wet	7 days — shoulder	24 mm (0.9 in)
October	3 days — shoulder	3 days — shoulder	4 days — shoulder	16 mm (0.6 in)
November	2 days — shoulder	2 days — shoulder	3 days — shoulder	19 mm (0.7 in)
December	5 days — wet	5 days — shoulder	7 days — wet	35 mm (1.4 in)

Phoenix is wet in Jul–Sep, Dec–Mar, shoulder in Oct–Nov and dry in Apr–Jun. Tucson is wet in Jul–Sep, shoulder in Oct–Feb and dry in Mar–Jun. Sedona is wet in Jul–Aug, Dec–Mar, shoulder in Sep–Nov and dry in Apr–Jun.

Monsoon rain comes as storms, not as long wet spells. Phoenix averages rain on 9 rain days in July, yet July and August are its wettest months, 37 mm (1.5 in) and 37 mm (1.5 in). Tucson gets more than twice Phoenix’s July rain — 92 mm (3.6 in) — and Sedona’s July, 75 mm (3.0 in), falls between the two. Over a whole year it is still desert: 263 mm (10.4 in) in Phoenix, 339 mm (13.3 in) in Tucson.

The wettest and driest months

Phoenix: wettest in July (37 mm (1.5 in), 9 rain days), driest in June (4 mm (0.2 in), 1 rain day). Tucson: wettest in July (92 mm (3.6 in), 18 rain days), driest in May (3 mm (0.1 in), 1 rain day). Sedona: wettest in July (75 mm (3.0 in), 15 rain days), driest in June (9 mm (0.4 in), 2 rain days). Over the year, Phoenix gets 263 mm (10.4 in).

The best months to go

Phoenix: Nov–Mar · Tucson: Feb–Apr, Nov · Sedona: Apr–May, Oct–Nov. When to Go rates every month on temperature, rain days and storms — open Phoenix in the tool above and step through the year.

Plan it

FAQ

When is the rainy season in Arizona?

Jul–Sep, Dec–Mar — the months that get more rain than an average month in Phoenix. July is the wettest, at 37 mm (1.5 in) across 9 rain days, against 4 mm (0.2 in) in June (NASA POWER, 2006–2025).

Does it rain all day in the rainy season in Arizona?

The measure here is a day with at least 1 mm of rain, not a day of rain. In July, Phoenix averages 9 rain days out of 31, with an average high of 106°F / 41°C.

What is the driest month in Arizona?

June, at 4 mm (0.2 in) across 1 rain day. The dry months, by the rule this page uses, are Apr–Jun.

When is the best time to visit Arizona?

When to Go rates Nov–Mar the best months for Phoenix, on temperature, rain days and — where it applies — storms. The other places on this page have their own; open the tool above on each.

When does monsoon season start in Arizona?

The National Weather Service dates it from June 15. The rain usually comes later than the calendar: June averages 4 mm (0.2 in) in Phoenix and 12 mm (0.5 in) in Tucson, against 37 mm (1.5 in) and 92 mm (3.6 in) in July.

When does monsoon season end in Arizona?

September 30, by the National Weather Service’s calendar. In this record September still brings 42 mm (1.7 in) to Tucson, the tail of the season, and October only 16 mm (0.6 in).

How these numbers are made

Daily rainfall and temperature from NASA POWER (MERRA-2), averaged over 2006–2025; a rain day is a day with at least 1 mm. POWER works on a grid of about 50 km, so each place here is its neighbourhood rather than its own rain gauge: a coast, a small island or a valley under a mountain can differ from the square it sits in. The months are the part that holds; treat a single millimetre figure as an average, not a forecast.