Economy, weather, and CO2
U.S. macroeconomics
To generate the macroeconomic assumptions in the Short-Term Energy Outlook (STEO), we input STEO energy price forecasts into S&P Global’s Short-Term U.S. Macroeconomic Model to produce a conditional macroeconomic forecast. For more details on the macroeconomic model, see our documentation.
Emissions
We forecast U.S. energy-related carbon dioxide (CO2) emissions to decrease by 2.2% in 2026 relative to 2025 and to increase by 0.5% in 2027 relative to 2026. In 2026, decreases in CO2 emissions are due primarily to expected declines in coal consumption, most of which occur at power plants for electricity generation. Declines in coal-fired generation and coal-related emissions are expected to continue in 2027 but are counteracted by growth in natural gas-fired generation, resulting in a modest increase in total CO2 emissions.
Weather
Based on our current forecasts and data from the National Oceanic and Atmospheric Administration, we expect the United States to average around 440 cooling degree days (CDDs) in the second quarter of 2026 (2Q26), slightly cooler than 2Q25 but higher than the 10-year quarterly average (3% more CDDs). Warmer weather in 3Q26 is expected to offset the cooler start to the summer (June–September) with 8% more CDDs than 3Q25. As a result, we expect the United States will average about 1,610 CDDs in 2026, 4% more CDDs than in 2025 and 5% more than the 10 year-average.
