Monthly average temperatures were 1 to 4 °F above the 1991-2020 normal for most of Arizona (light orange, orange, and dark orange areas on map), except for the southern tier of the state where temperatures were near normal for many locations (white areas on map). For reference, monthly average temperatures in May 2025 were near normal for much of the state.

Area-average maximum and minimum temperatures during May 2026 were 80.7 and 51.7 °F for the Sonoita AVA, 86.3 and 53.0 °F for the Verde Valley AVA, and 84.5 and 51.6 °F for the Willcox AVA. Respective May normals are 81.7 and 49.6 °F, 84.5 and 50.0 °F, and 84.8 and 48.9 °F.

Temperature last month ranged between 95.5 and 41.4 °F at the AZMet Bonita station, 92.8 and 36.0 °F at the AZMet Elgin station, and 95.5 and 41.2 °F at the AZMet Willcox Bench station.

Monthly precipitation totals were more than 125 % of normal for much of the southeastern part of the state (various aqua and blue areas on map). These locations transitioned quickly to those measuring amounts less than 50 % of normal for most of the rest of the state (yellow and dark yellow areas on map), except along the Mogollon Rim where amounts were near normal (white areas on map). Precipitation during May 2025 was more than 250 % of normal for much of the west-central part of the state. In contrast, much of the southeastern part of the state saw totals less than 75 % of normal. Amounts were near normal for much of the northeastern corner of Arizona.

Area-average precipitation totals in May 2026 were 0.46 inches for the Sonoita AVA, 0.35 inches for the Verde Valley AVA, and 0.63 inches for the Willcox AVA. Respective May normals are 0.22, 0.44, and 0.29 inches.

Total precipitation last month was 0.11, 0.10, and 0.10 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.

Learn more about PRISM climate data.

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 June 2025 were 1 to 4 °F above normal for much of the southeastern, central, and northern parts of Arizona. Much of the rest of the state saw near-normal temperatures.

Area-average maximum and minimum temperatures during June 2025 were 92.1 and 61.1 °F for the Sonoita AVA, 97.1 and 61.1 °F for the Verde Valley AVA, and 95.5 and 62.2 °F for the Willcox AVA. Respective June normals are 90.6 and 59.0 °F, 95.4 and 58.4 °F, and 94.5 and 59.1 °F.

Temperature in June last year ranged between 104.2 and 54.0 °F at the AZMet Bonita station and between 105.1 and 56.3 °F at the AZMet Willcox Bench station.

Precipitation totals for this month have a slight increase in chances for being above normal across much of the eastern one-third of the state (light aqua and aqua areas on map). For the rest of Arizona, there are equal chances for below-, near-, or above-normal totals (white area on map). Largely due to rain at the start of the month from a cut-off low pressure system that brought moisture from tropical depression Alvin into the state rather than an early start to the monsoon, precipitation during June 2025 was more than 250 % of normal for many parts of the state. Only a few locations in southeastern and east-central Arizona failed to post such impressive statistics in, granted, what is a typically dry month.

Area-average precipitation totals in June 2025 were 0.90 inches for the Sonoita AVA, 0.98 inches for the Verde Valley AVA, and 0.82 inches for the Willcox AVA. Respective June normals are 0.55, 0.18, and 0.42 inches.

Total precipitation in June last year was 0.64 and 0.72 inches at the AZMet Bonita 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.

Heat accumulation during the April-May period this year at the AZMet Willcox Bench station in the south-central part of the Willcox AVA is greater than what it was last year (top two rows of table). This suggests that the growth rate of vines may have been faster and the time between pre-veraison growth stages shorter so far this growing season than what they were in the previous one. Heat accumulation this year is above average, as indicated by the positive percent value in the third table column, and the greatest it has been during the April-May period since station measurements began.

Relative to last year, how much more advanced might vine growth stages be this year due to the additional heat accumulation? As daily accumulation of growing degree hours during the April-May period is about 280 on average, and the difference in cumulative growing degree hours between 2026 and 2025 is 2,260, the additional heat accumulation during April-May 2026 is worth about eight days. Coupling this with bud break dates in 2026 that we’ve heard were the earliest ever, growth stages might be about three weeks ahead of where they were last year, depending on variety.

Digging more into the flowering and veraison dates from Buhl Memorial Vineyard during the 2023 through 2025 growing seasons, the average amount of time between these two vine growth stages across varieties is about eight to 11 weeks, with a range from 59.0 days (Tempranillo) to 77.7 days (Petit Verdot).

In terms of heat accumulation, an average of 18,732.2 growing degree hours occurs between these two vine growth stages across all varieties, with a range from 16,028.2 (Tempranillo) to 21,658.4 (Petite Verdot). These values are based on temperature data from the AZMet Willcox Bench station in the south-central part of the Willcox AVA.

A few points come to mind from these statistics and other ones shown in the table. Despite data from just a few growing seasons, variability in average duration and heat accumulation among the varieties may reflect their genetic variability. Also, given heat accumulation during the April-May 2026 period relative to that from the three previous years, one might expect the amount of time between flowering and veraison for all varieties this growing season to be less than the minimum duration observed during the 2023 through 2025 growing seasons. And finally, ranges of duration and heat accumulation for an individual variety may suggest that windier conditions are decoupling the developmental rate of the vine from what is inferred from heat accumulation alone. Higher wind speeds increase evapotranspiration demand at a given temperature, potentially decreasing carbon dioxide uptake by the vine and slowing its metabolism.