San Diego County reports 499 new COVID-19 cases San Diego County is in the most restrictive purple tier, but numbers are trending down at such a rate the county could be promoted to the red tier this month. Author: City News Service Updated: 6:40 PM PST March 5, 2021 SAN DIEGO COUNTY, Calif. — Stadiums and theme parks were cleared today to Friday in California beginning April 1 subject to strict conditions. Theme parks can reopen at 15% capacity in the red tier of the state's four-tiered reopening plan. Capacity levels will shift to 25% in the orange tier and 35% in the yellow tier. San Diego County is in the most restrictive purple tier, but numbers are trending down at such a rate the county could be promoted to the red tier this month.