Weather in Tucson in September

A hard month. September is a hard month in Tucson, and worth planning around. Daytime highs average 35 °C and the afternoon is not negotiable — outdoor plans move to early morning or evening.

September ranks 9 of 12 in Tucson: past the worst of the year but short of March, which is the month to book if the dates are open.

Rain on 8 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for heat management rather than style: shade, water, and a schedule that gives up on the middle of the day.

What the averages hide

Averages flatten a month, and this one hides a few things: 16 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest September day reached 42.3 °C and the coldest night fell to 12.8 °C, and the wettest single day dropped 40 mm — roughly 98% of the month's rain in one day.

September is moderately variable: 4 mm in the driest year against 95 mm in the wettest, around an average of 41 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 7.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 46%.

How September sits in the year

The month is on the way down: 1.6 °C cooler than August, with October dropping another 4.6 °C. The first week and the last are not the same trip. Rain is the thing that moves: October brings 5 days less of it, so pushing the dates later buys drier weather.

Daylight in September

12.4 hours of daylight, losing 1 hours across the month. That is between Tucson's extremes of 14.2 and 10.1 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 34.5 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage. At 759 m the air is thin enough to matter — sun that burns faster than the temperature suggests, and nights that cool off quickly. Within September itself the daily swing is 14 °C, so mornings and afternoons need different clothes.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Tucson versus nearby

If Tucson is one option among several, the nearby comparison is worth making. Phoenix is the weaker option in September — 3.6 °C warmer, 4 days less rain. Sedona is a better bet in September — 4.2 °C cooler, 1 day less rain.

So: September is a compromise. March is 49 points better and is what Tucson is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Tucson

See all twelve months in Tucson, or where else to go in September.