The overall positivity rate is expected to go from 3.9% to 3.1% and the daily case count per 100,000 people is expected to drop from 4.7 to 3.6, Kim said. The percentages could be up or down, but in that neighborhood, he added.
"There has been a steady but consistent decline in testing positivity rate," Kim said. "Things are looking good."
Moving up to the orange tier means that more businesses would be allowed to further reopen. Retail businesses and malls could operate at full capacity, instead of at 50% capacity in the red tier.
Churches, restaurants, movie theaters, zoos and aquariums would be allowed to operate at 50% capacity. Gyms and fitness centers can boost capacity to 25% under the orange tier.
Amid those improving numbers, some students went back to their campuses on Tuesday morning, just weeks after the county moved up from the purple tier, the most restrictive, to the red tier.
Though the county's schools are now eligible to reopen, not all of them will do so right away.
It is up to individual school districts to decide and many are offering "hybrid models" of some in-person instruction and some online-only instruction, Orange County CEO Frank Kim said Monday.
Some school districts will allow parents to continue with distance learning only.
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At Mater Dei High School in Santa Ana, students will be back 25% of the time - or half of the day, twice a week.
The Diocese of Orange County has been keeping a close eye on opportunities to reopen schools since waivers were offered earlier this summer. Earlier this month, 30 Catholic elementary schools secured those waivers and were able to return to in-person learning, keeping them immune from any changes in the county's metrics.
Some of the other districts reopening campuses are Capistrano Unified School District and Fountain Valley School District.
But, of course, certain health measures in order to prevent the spread of COVID-19 must be in place, including spaced out desks and staggered drop-off and pick-up times for students. Face masks are optional for kids up to third grade but required for older students, barring any physical or mental health conditions.
City News Service contributed to this report.