Monthly average temperatures were 3 °F to more than 5 °F above the 1991-2020 normal for most of Arizona (dark orange, red-orange, and dark red-orange areas on map). For reference, monthly average temperatures in August 2025 were 1 to 4 °F above normal for much of the state. Some central and south-central parts of Arizona saw temperatures more than 4 °F above normal.

Area-average maximum and minimum temperatures during August 2026 were 91.2 and 64.9 °F for the Sonoita AVA, 100.3 and 70.1 °F for the Verde Valley AVA, and 96.8 and 66.9 °F for the Willcox AVA. Respective August normals are 86.3 and 61.7 °F, 95.7 and 65.2 °F, and 91.2 and 63.8 °F.

Temperature last month ranged between 103.3 and 63.3 °F at the AZMet Bonita station, 99.7 and 61.2 °F at the AZMet Elgin station, and 104.2 and 62.6 °F at the AZMet Willcox Bench station.

Monthly precipitation totals were either near normal (white areas on map) or between 25 and 75 % of normal (yellow and light-yellow areas on map) for most locations in a scattered pattern across the state. Precipitation during August 2025 was between 25 and 75 % of normal for many parts of the state, with several locations in south-central, northeastern, and northwestern Arizona measuring amounts less than 25 % of normal.

Area-average precipitation totals in August 2026 were 3.58 inches for the Sonoita AVA, 2.25 inches for the Verde Valley AVA, and 2.22 inches for the Willcox AVA. Respective August normals are 3.95, 2.40, and 2.80 inches.

Total precipitation last month was 1.02, 2.96, and 2.47 inches at the AZMet Bonita, Elgin, and Willcox Bench stations, respectively.

Dig further into daily weather summaries for the AZMet Bonita and Willcox Bench stations in the Willcox AVA and the AZMet Elgin station in the Sonoita AVA.

View seasonal summaries of monsoon rainfall through regional maps and weather station statistics.

Learn more about PRISM climate data.

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Temperatures over the course of this month have a slight increase in chances for being above the 1991-2020 normal across all of Arizona (light-orange and orange areas on map). Monthly average temperatures in September 2025 were within 2 °F of normal for most of the state.

Area-average maximum and minimum temperatures during September 2025 were 83.2 and 60.2 °F for the Sonoita AVA, 89.8 and 61.5 °F for the Verde Valley AVA, and 86.4 and 61.6 °F for the Willcox AVA. Respective September normals are 83.9 and 57.0 °F, 90.4 and 58.4 °F, and 87.8 and 58.3 °F.

Temperature in September last year ranged between 96.1 and 52.7 °F at the AZMet Bonita station, between 93.6 and 50.5 °F at the AZMet Elgin station, and between 97.0 and 53.1 °F at the AZMet Willcox Bench station.

Precipitation totals for this month have a slight increase in chances for being above normal across all of the state (light-aqua and aqua areas on map). Precipitation during September 2025 was more than 125 % of normal for many extreme-western, central, east-central, and southeastern parts of the state. Many locations in south-central and north-central Arizona recorded near-normal totals, with some along the northern state border recording below-normal amounts.

Area-average precipitation totals in September 2025 were 2.72 inches for the Sonoita AVA, 2.27 inches for the Verde Valley AVA, and 2.70 inches for the Willcox AVA. Respective September normals are 1.95, 1.53, and 1.40 inches.

Total precipitation in September last year was 1.89, 2.42, and 1.49 inches at the AZMet Bonita, Elgin, and Willcox Bench stations, respectively.

To stay informed of long-range temperature and precipitation possibilities beyond the coverage of a standard weather forecast, check in, too, with the six-to-ten-day outlook and eight-to-fourteen-day outlook issued daily by NOAA’s Climate Prediction Center.

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To help put the ripening period this year in perspective, we return to tracking hours of temperatures below 65 °F and above 95 °F. The reason why is that temperatures affect fruit quality through both early morning minimums and afternoon maximums as fruit ripens. With the former, for example, morning minimums above 65 °F can increase malic acid metabolism and lead to berries with a higher pH. With the latter, afternoon maximums above 95 °F can degrade anthocyanins, particularly in red-berry varieties.

Based on data from the AZMet Willcox Bench station in the Willcox AVA, conditions in August 2026 led to five days with average hourly temperatures over 100 °F (dark red bars on top graph), for a total of 13 hours. The highest average hourly temperature was 102.6 °F on August 25. Temperatures between 95 and 100 °F occurred on 22 days (light red bars on top graph), for a total of 80 hours. In August 2025, for comparison, there were six days and 23 hours with average hourly temperatures above 100 °F, and 11 days and 39 hours between 95 and 100 °F (dark and light red bars, respectively, in second-from-top graph). Heat exposure this year appears more concentrated during the earlier and latter parts of the month.

There were 10 days during August 2026 with average hourly temperatures between 60 and 65 °F (light blue bars on top graph), for a total of 13 hours. Temperatures less than 60 °F (dark blue bars on top graph) did not occur. The lowest average hourly temperature was 63.7 °F on August 24. During August 2025, for comparison, there were five days and nine hours with average hourly temperatures between 60 and 65 °F, and no days less than 60 °F (light and dark blue bars, respectively, in second-from-top graph).

The increase in humidity due to the monsoon during July and August is a typical feature that keeps daily minimum temperatures higher, as less heat radiates away from the surface and into the upper levels of the atmosphere during the night. Based on data from the previous four growing seasons, one might expect increasing exposure to temperatures below 65 °F for varieties still ripening during September, at least near this location. Little exposure to temperatures over 95 °F, particularly during the first part of the month, might also be anticipated.

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Oceanic and atmospheric conditions over the equatorial Pacific Ocean continue to reflect present and strengthening El Niño conditions. Chances for a very strong event between now and the November-2026-through-January-2027 period are greater than 90 %. There is a 69 % chance that the current event exceeds the strength of events since 1950. Chances of impacts to regional weather are greater with strong events, but impacts are not guaranteed. Nor are they certain to be characterized as “strong”, should they occur.

As a quick refresher regarding impacts, we’ll reference this map from NOAA NCEI that shows sea-surface temperatures (SSTs) around the globe. Below-average SSTs are shown in the cooler colors (blue and purple areas on map) and above-average SSTs in the warmer colors (yellow, orange, and red areas on map). Locate the southwestern part of North America (gray land mass right of map center and north of equator). The two red areas to our south are two of several characteristics of El Niño events. Above-average SSTs off the western coast of Mexico are one ingredient that helps increase tropical cyclone activity, the storms or moisture of which can move into our region, resulting in additional rainfall. Above-average SSTs along the central and eastern equatorial Pacific Ocean fuel broad areas of large convective storms above. The upward and outward movement of these powerful storms effectively ripples through the atmosphere – picture the result of large rock thrown into a small pool – bumping against and redirecting the jet stream, or winter storm track, such that it might pass through the Southwest more often, increasing chances for precipitation.

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