A brief moderation in daytime temperatures for the holiday weekend will give way to a rapid warm-up next week, with Phoenix forecast to climb well into the triple digits and a midweek high of about 114 degrees possible. Clouds moving across the state, most pronounced in southern Arizona, will keep daytime highs on the low side for the holiday itself, but meteorologists warn that the cloud cover also will limit overnight cooling, leaving nights noticeably warmer than recent weeks.
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7-day outlook graphic showing Phoenix could reach 114°F on Saturday, with triple-digit highs expected through next week.
Forecasts show Saturday’s daytime high in Phoenix around 105 degrees, a number held down by mostly cloudy skies. Meteorologists describe that as a below-average temperature for the Fourth of July period, but the relief will be temporary. Officials say the cloud layer will act to keep overnight temperatures elevated across much of the region, effectively ending the recent stretch of lows in the 70s for metro Phoenix. Instead, lows through the holiday weekend are expected to rise into the mid-80s in many locations.
Broadcast weather graphic with meteorologist forecasting 105°F and 'lots of clouds' for Phoenix tomorrow, reflecting a slightly cooler holiday before temperatures rise.
The ridge of high pressure responsible for the impending warm-up is forecast to build in from the east as the clouds clear Sunday. That shift should push daytime readings back upward; Sunday’s forecast high is about 109 degrees, and the peak warmth is expected by midweek when models place Phoenix near 114 degrees. Forecasters say there is a possibility of issuing a First Alert for heat on at least one day next week, though they emphasized more lead time is needed before confirming specific alert days. They are monitoring the situation closely and will increase confidence in precise temperatures as the event draws nearer.
Beyond the immediate temperature outlook, meteorologists outlined the state’s broader moisture and thunderstorm prospects. At present, there is no setup indicating a strong surge of monsoon moisture into central Arizona. Instead, conditions favor only limited thunderstorm redevelopment, chiefly in southeast Arizona where localized storms are more likely to occur. One model scenario points to a potential window for afternoon and evening storms around Sunday, July 12; however, forecasters say confidence in that scenario is low and it remains only one of several possibilities.
Local weather teams are encouraging residents to stay tuned for updates as the week progresses. The possibility of a heat alert, combined with the forecast spike to the mid-110s, means that agencies responsible for public messaging will be watching model trends closely. The meteorological services that provide the First Alert Weather App have been cited as a source for the latest short-term updates and any alert notifications. Forecasters reiterated the need to check updated guidance in the days immediately ahead to see whether the projected high-confidence warming trend solidifies or changes.
For the holiday weekend itself, the most immediate impacts will be the persistent cloud cover and warmer nights. The clouds are expected to be especially notable over southern parts of the state, and their presence will moderate daytime peak readings on Saturday even as they prevent the usual overnight cooling. By Sunday, as the skies clear and the pressure ridge strengthens, the trend will reverse and the heat will return in earnest. Forecast discussions make clear that, while a cooler holiday day is on tap, the region is on the cusp of a fast and significant warming trend going into the middle of next week.
As of the latest forecast cycle, forecasters stress that details can change with evolving model runs and that the degree of confidence will improve as the warm spell approaches. They have identified the potential for an official heat alert but are not committing to a specific day until models converge further. Meanwhile, isolated thunderstorm activity remains most plausible in southeast Arizona rather than across the Phoenix area, and while there is a scenario that could produce storms in the Valley around July 12, that outcome currently carries low confidence. Weather services will continue to provide updated forecasts and any official notices as more data become available.
Meanwhile, 12News reports a spike in heat-related deaths across Maricopa County compared to the same time last year, highlighting the risks as another round of extreme heat approaches the region.
The Maricopa County Department of Public Health’s April 2026 annual heat report shows 430 heat-related deaths in 2025, and the county this year has launched an interactive heat‑related illness and death dashboard that will be updated weekly during the May–October heat season to provide preliminary counts and hospital visit data.
The National Weather Service’s product guidance (NWS Instruction 10‑515 and regional supplements) notes that local weather offices typically issue Excessive/Extreme Heat Watches or Warnings when conditions are expected to meet locally defined warning criteria—commonly on the order of daytime heat indices or temperatures near 110°F for two consecutive days combined with overnight lows in the mid‑to‑upper 70s—though exact thresholds vary by forecast office and location.
For context, NOAA/NWS climate normals for the Phoenix Sky Harbor station (1991–2020) show a July average high of about 106.5°F, so a forecast high near 105°F for the holiday is slightly below the long‑term July mean while a midweek 114°F reading would be roughly 7–8°F above the typical July high for Phoenix.