Why it’s hard to grade definitively

Chamath’s prediction (11 April 2020) was essentially:

1. Baseline: California would not be "out of lockdown" before June 1, 2020.
2. Conditional: If April case curves were decaying, Governor Newsom would lift the lockdown sometime between mid‑May and late May 2020 at the earliest.

The problem is what counts as “lifting” or being “out of lockdown”:

What actually happened in California

• California’s statewide stay‑at‑home order was issued March 19, 2020 and remained in force as the legal framework throughout 2020; it was not fully terminated until June 15, 2021, when Newsom lifted the stay‑at‑home and tier system as the state “fully reopens.” (gov.ca.gov)
• On April 14, 2020, Newsom outlined six indicators that would guide when and how to modify the stay‑at‑home order, explicitly tying reopening to sustained flattening/decline of hospitalizations and other metrics. (gov.ca.gov)
• On May 4, 2020, Newsom announced that, based on progress on those indicators, California could move into the early phase of Stage 2 on Friday, May 8, beginning to modify the stay‑at‑home order. This allowed certain lower‑risk workplaces (e.g., curbside retail, some manufacturing and logistics) to reopen with adaptations. (gov.ca.gov)
• On May 7, the state released detailed industry guidance and confirmed that California would begin modifying the stay‑at‑home order on May 8 with these partial reopenings. (gov.ca.gov)

So:

• Partial easing / modification of the “lockdown” clearly started May 8, 2020 (early–mid May).
• Legal end of the stay‑at‑home order and most associated restrictions did not occur until June 15, 2021.

Comparing to Chamath’s prediction

1. "We’re not going to get out of lockdown until June 1 at the earliest"

• If you interpret “get out of lockdown” to mean any significant easing or modification of the stay‑at‑home regime, this is false: the state began reopening (Stage 2, curbside retail and more) on May 8, 2020, well before June 1. (gov.ca.gov)
• If you interpret it as fully ending the stay‑at‑home order and returning to broadly normal activity, then it is actually too optimistic: the order and tiered restrictions persisted long past June 1, 2020 and were only fully retired in June 2021. (gov.ca.gov)

2. "If April curves are decaying, it’s going to be mid‑May to late May before he lifts this thing"

• By mid‑April, Newsom was already talking about flattening curves and criteria for modifying the order. (gov.ca.gov)
• The first concrete easing of restrictions tied to those criteria began May 8. That’s slightly earlier than “mid‑May”, but within the same general mid‑May timeframe that he described.

So under a partial‑reopening definition of “lift,” the timing of lifting (early–mid May rather than mid–late May) is roughly in the ballpark, but the "not before June 1" component is wrong; under a full‑end‑of‑order definition, the “not before June 1” is right but the idea that the lockdown would be lifted around May/June 2020 at all is wrong.

Why the verdict is ambiguous

• The prediction bundles together conflicting timing statements ("not…until June 1" vs. "mid‑ to late May") and uses an imprecise concept (“get out of lockdown,” “lift this thing”) in a situation where California explicitly chose a phased modification of the stay‑at‑home order rather than a single clear lifting date.
• Depending on which reasonable interpretation you adopt—any easing vs. full termination of the order—you can argue it was partly right or clearly wrong.

Because the outcome hinges on subjective interpretation of “lockdown lifted” rather than on a clean factual discrepancy, the prediction cannot be graded as simply right or wrong; hence "ambiguous".