James Hansen

The 12-month running-mean global temperature will bottom out at about +1.4°C (vs 1880-1920) in the first half of 2026 before rising again.

“The 12-month running-mean temperature should decline for the next few months, reaching a minimum about +1.4°C.”

Said on

18 December 2025 · Hansen, Kharecha, Morgan and Vest, "Global Temperature in 2025, 2026, 2027", 18 December 2025; the body says the minimum is expected "in the first half of 2026". GISS analysis, 1880-1920 baseline.

Source

Global Temperature in 2025, 2026, 2027 · James Hansen (Substack)

Should come true

Q2 2026

How sure they sounded

should

Categories

Climate

Importance

2 of 5 · Short-term test of the acceleration thesis (a La Nina minimum above prior El Nino peaks).

Outcome

Accurate Happened 30 April 2026.

From GISTEMP v4 monthly data, the 12-month running mean fell to about +1.15°C vs 1951-1980 for May 2025-Apr 2026. With the 1880-1920 mean at -0.27°C, that is about +1.42°C on his baseline. It has risen since (about +1.48°C through Sep 2026), matching the forecast minimum of about +1.4°C in the first half of 2026.

Evidence:

• https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt
• https://www.columbia.edu/~jeh1/mailings/2026/ElNino.2026.02.06.pdf