California’s recent scholastic heat-safety legislation, AB 2503, requires the California Interscholastic Federation (CIF) to review and update the guidelines, procedures, and safety standards surrounding scholastic heat safety on an annual basis.
The law finds and declares that in acclimatized desert regions, where students and communities routinely experience prolonged high temperatures, the current 92.1 degrees Fahrenheit WBGT threshold is overly restrictive. It brings a central question in high school athletics into focus: How can schools protect student-athletes from extreme heat while still preserving their opportunities to practice and compete?
AB 2503 at a glance
AB 2503 passed unanimously through California’s Assembly on May 11, 2026, and through the Senate on August 17, 2026. The bill challenges how CIF balances heat-related health risk in practicality across California’s varied regional climates.
What does AB 2503 currently require?
California’s AB 2503 amends Section 25179.8 of California’s education code, requiring CIF to review its heat safety guidelines on or before July 1, 2027, and on an annual basis after that.
What did AB 2503 originally propose?
The original bill, put forth by 47th district Assemblymember Greg Wallis, aimed to raise WBGT limits for parts of Region Category 3 zones, including the Coachella Valley and other adjacent areas where the CIF prohibits outdoor activities at WBGT readings exceeding 92 degrees Fahrenheit.
It suggested the establishment of a specialized regional category for extreme desert climates that would allow outdoor practices with enhanced safety protocols, citing acclimatized populations. The bill aimed to put forth additional safety measures, including but not limited to mandatory hydration breaks every 15 minutes, onsite monitoring by trained personnel, and enhanced heat acclimatization protocols for this group. It offered the opportunity for additional safeguards, when supported by peer-reviewed research.
The bill was originally written to authorize a new threshold that raised thresholds to a WBGT of 93.5 degrees Fahrenheit contingent on updated peer reviewed research for the so-called region zone four. In the original language, it sought to prohibit the threshold from ever being lowered below a WBGT of 93.5 degrees Fahrenheit upon further revision.
Why was AB 2503 originally proposed?
Proponents of AB2503 cited logistics and scheduling challenges as the main reason why CIF’s WBGT thresholds might need to be amended. Schools in California’s extreme desert regions frequently see practices go late in the evening – which disrupts family routines and impacts academic and athletic performance.
“Our student athletes in desert communities deserve guidelines that reflect where they actually live and compete,” said Assemblymember Wallis. “This bill is about making sure our kids can participate in the sports they love, with strong safety protections in place, while giving families and coaches the predictability they need.”
AB 2503 builds on California’s existing scholastic heat safety requirements by requiring CIF to further consider the evolving needs of the state’s hottest regions.
Why do California’s heat regions create different athlete risks?
California’s diverse geography creates distinct heat regions that affect athletes differently – variations in ambient temperature, humidity, sunlight, and wind all affect how a student athlete experiences heat. And due to geographic variations in heat exposure and acclimatization, higher heat safety thresholds may be appropriate in areas with hotter climates.
The table below can be used to identify CIF Wet Bulb Globe Temperature Activity Guidelines.
For more on CIF’s heat policy, see here.
Does AB 2503 change CIF’s current WBGT limits?
AB 2503 does not currently raise CIF’s existing Wet Bulb Globe Temperature (WBGT) limits or establish a separate category for extreme desert climates, although that was a part of the original proposed bill. Instead, it requires CIF to review its heat illness prevention guidelines by July 1, 2027, and annually thereafter, updating them as necessary with special consideration for regions with higher average temperatures.
Although the original proposal included a higher WBGT threshold for certain desert communities, that change wasn’t included in the final law. Schools should continue following the applicable CIF heat guidelines while awaiting any revisions resulting from the 2027 review.
How are desert schools adapting to CIF’s heat guidelines?
In California’s desert communities, early-morning and evening practices have become part of how schools manage complying with CIF’s heat restrictions in desert climates. But adjusting to those schedules — and changing them when conditions shift — has created challenges for coaches, students, and families.
At Palm Springs High School, athletic trainer Andrea Zavala says the new CIF guidelines have helped coaches increasingly plan around the heat. When she first arrived, teams frequently delayed or canceled practices because their scheduled start times fell during hotter hours. But now, coaches anticipate those restrictions, and often schedule practices for 6 p.m. during hotter periods.
“Everyone knows now, so it’s not a surprise,” Zavala says.
The harder adjustment comes when conditions fluctuate. Zavala describes weeks when teams could begin at 4 or 4:30 p.m., followed by hotter weather that pushed practices back to 6:30 p.m. Earlier starts give students more of their evenings back, but repeatedly changing the schedule makes it harder for families to plan. Keeping a consistent, later start can offer more predictability for students, families, and staff.
At Rancho Mirage High School, athletic trainer Kendra Calderon describes what those later practices mean for students. Some can go home, eat, and return before practice. Others lack transportation or live more than 30 minutes away, leaving them on campus between the end of classes and the start of athletics.
“Starting school at 8:45 in the morning and not leaving till 8:45 at night is a very long day,” Calderon says.
What should the CIF’s annual review of its heat guidelines consider?
For Kendra, the current WBGT restrictions raise questions about how statewide guidelines account for everyday desert conditions. When discussing the one-hour red zone practice limit and equipment restrictions, she says “That’s nothing to us,” adding, “The red zone is what we live in.”
Her point is that conditions triggering substantial practice modifications are familiar to the students and staff in her community. She wants CIF’s review to examine how that regional experience — and athletes’ acclimatization — should inform the restrictions and WBGT zones, while maintaining protections against heat illness and upholding student safety.
“I would like to go back to the higher 93, but we’ll start in small steps,” says Calderon. She believes even a one-degree increase could allow practices to begin at least an hour earlier under conditions she regularly observes.
But implementing a higher threshold, like the one originally suggested by California AB 2503, would raise questions about how schools prepare athletes for the change. Kendra believes that moving practices out of hotter hours has affected students’ familiarity with exercising in those conditions, even though most student athletes have been living in the valley for their whole lives.
“We’re worried about the kids’ health and making sure they’re safe, and we’re definitely not deviating from that,” Kendra says.
Now in her 14th football season at the school, she recalls just one heatstroke case that occurred during a Saturday morning practice. She says another local athletic trainer, who has worked in the area longer, recalled a similar case that occurred early, before WBGT readings would have suggested precautions.
“Between March and April, and then getting into May, we heat up fast,” says Calderon.
That makes acclimatization an important part of the threshold discussion. Kendra points to a nearby community college’s more gradual progression of activity as an example of the preparation she would like examined. For CIF’s review, the question becomes both whether a higher desert WBGT limit is supported by research and how schools would prepare athletes to acclimatize and operate under any changes.
Zavala shares that priority. “A successful outcome would allow teams to start practice more consistently around 4:30 or 5 p.m., helping students get home earlier.” But whether a threshold change is appropriate, and what safeguards should accompany it, requires further evaluating research alongside schools’ experiences.
The bottom line
California AB 2503 creates an annual review process for CIF’s heat safety guidelines, with special consideration for the state’s hotter regions. It doesn’t raise WBGT limits, so schools should continue following the applicable CIF restrictions.
For desert schools, the review offers an opportunity to bring local data and athletic trainers’ experiences into the discussion. Their priorities include more predictable practice schedules, regional thresholds supported by research, and acclimatization practices that prepare students for any changes.
The goal is to protect student-athletes while preserving their opportunities to practice and compete — and giving them more of their school day back.
