Arizona runs on two calendars. The low deserts around Phoenix, Tucson are at their best from November to April and dangerously hot in summer. The high country around Flagstaff and the Grand Canyon, where the South Rim sits at 7,000 feet, has real winters and is at its best from May to October. Picking a month means deciding which half of the state you want most.
The temperatures below are 1991-2020 averages from NOAA. Seasonal dates are for 2026 or the 2027 season where the managing agency has published them.
The two halves of the state
| Month | Phoenix high / low | Tucson high / low | Flagstaff high / low | Grand Canyon (airport) high / low |
|---|---|---|---|---|
| January | 68 / 46 °F | 67 / 41 °F | 43 / 18 °F | 44 / 16 °F |
| February | 71 / 49 °F | 69 / 43 °F | 46 / 20 °F | 47 / 17 °F |
| March | 78 / 55 °F | 76 / 48 °F | 52 / 24 °F | 55 / 22 °F |
| April | 86 / 61 °F | 83 / 53 °F | 59 / 28 °F | 61 / 25 °F |
| May | 95 / 70 °F | 92 / 62 °F | 68 / 35 °F | 71 / 32 °F |
| June | 104 / 79 °F | 101 / 71 °F | 79 / 43 °F | 83 / 38 °F |
| July | 107 / 85 °F | 100 / 76 °F | 82 / 51 °F | 85 / 49 °F |
| August | 105 / 84 °F | 99 / 75 °F | 79 / 51 °F | 83 / 49 °F |
| September | 100 / 78 °F | 95 / 70 °F | 74 / 43 °F | 77 / 40 °F |
| October | 89 / 66 °F | 86 / 59 °F | 64 / 32 °F | 66 / 30 °F |
| November | 77 / 54 °F | 75 / 48 °F | 52 / 23 °F | 54 / 21 °F |
| December | 66 / 45 °F | 66 / 41 °F | 43 / 17 °F | 44 / 14 °F |
The inner canyon is a third climate: temperatures rise about 5.5 °F for every 1,000 feet you descend, and summer highs at Phantom Ranch average around 30 °F warmer than on the rims, according to NPS.
Month by month
January and February. Desert hiking season: Phoenix and Tucson average highs in the upper 60s and lows in the 40s. Flagstaff averages about 20 inches of snow in January. At the Grand Canyon, Hermit Road is open to private cars (under 22 feet) only in December, January and February; the rest of the year a free shuttle replaces them. The North Rim is closed. Fee-free day: February 16 in 2026 (US residents only).
March and April. Peak season across the south. Spring break makes March and April among the busiest months at the Grand Canyon, where NPS reports entrance waits of up to two hours between 10 a.m. and 4 p.m. on busy days. Desert highs climb from the upper 70s into the mid-80s. Navajo Nation clocks move forward on March 14, 2027, putting Monument Valley and Canyon de Chelly an hour ahead of the rest of Arizona. Fossil Creek's parking permit season starts April 1, and two overnight trips to Keet Seel run in April.
May. The switch-over month. Phoenix averages 95 °F, so desert hiking moves to early morning. The North Rim normally opens May 15, and the North Rim campground's tentative 2027 reopening date is May 15. Havasupai's peak season runs May to September, by the tribe's description. Another two Keet Seel trips run in May. Memorial Day (May 25 in 2026) is a fee-free day for US residents. Memorial Day starts the summer rush at the Grand Canyon and the season of Betatakin ranger hikes.
June. The hottest, driest month in northern Arizona before the monsoon, and the peak of the fire season there, according to the National Weather Service in Flagstaff. Phoenix averages 104 °F. The NPS urges caution for inner canyon hikers from May to September.
July and August. Monsoon. The season officially runs June 15 to September 30, and moisture usually reaches northern Arizona in the first week of July, bringing afternoon thunderstorms, lightning and flash floods. Phoenix averages 105 to 107 °F. The high country is at its warmest (low 80s in Flagstaff) and busiest. Fee-free days in 2026 were July 3 to 5 and August 25.
September. Storms thin out, though NWS notes the late monsoon can bring the most severe weather when Pacific troughs meet lingering moisture. Keet Seel trips resume, and the Betatakin hike season ends on Labor Day. September 17 was a fee-free day in 2026.
October. The best all-round month if you want both halves of the state: Phoenix averages 89 °F, the Grand Canyon 66 °F. Fossil Creek permits end October 1; the last Keet Seel trips run. In a normal year the North Rim's full season ends October 15.
November. Desert season begins again, with Phoenix highs in the high 70s. Navajo Nation clocks fall back (November 1 in 2026), so the whole state shares one time until March. November 11 (Veterans Day) is a fee-free day for US residents at national parks, and Arizona State Parks gives veterans and service members free day use that day. The North Rim's road closes for the winter on November 30 or at the first major snowstorm.
December. Short days and snow on the plateaus: Flagstaff averages about 18 inches. The North Rim and State Route 67 are closed to all vehicles from December 1 to May 14. Hermit Road reopens to cars.
Arizona in late 2026
Two events change this winter's calendar:
- Grand Canyon: in-park lodging has been halted since August 31, 2026, after a flood cut the South Rim's water supply. NPS gave Thanksgiving as a tentative start for a phased return of overnight guests. The South Rim remains open for day visits.
- Sedona: after the November 1 flood, State Route 89A through Oak Creek Canyon was closed between Sedona and Kachina Village with no reopening estimate as of November 3. On November 6 ADOT reopened the road from Sedona to Slide Rock State Park, which Arizona State Parks said would reopen on November 7; the canyon north of the park stays closed.
So which month?
- Desert parks and hiking: November to April.
- Grand Canyon, Flagstaff and the plateaus: May to October, with April and October the quieter shoulders.
- North Rim: only from May 15 to the first snow, in a year when services are running.
- Avoid: desert hiking from June to September, and slot canyons whenever storms are forecast anywhere upstream.
Details checked 6 November 2026.
