2025 forecasted to rival 2024 for record-breaking heat

Environment and Climate Change Canada’s (ECCC) forecast for global temperature indicates 2025 will likely see heat approaching but not exceeding 2024, the hottest year on record.

The Canadian Centre for Climate Modelling and Analysis is forecasting a global mean surface temperature of 1.45 ± 0.10 °C above pre-industrial levels in 2025, slightly cooler than the record high temperature of 1.55 °C seen in 2024 but virtually certain (>99% chance) to be hotter than every year on record prior to 2023. High temperatures are forecasted to persist despite the end of the El Niño event that warmed the tropical Pacific and boosted global temperatures in 2023 and 2024.

2025 AGMT Forecast

The observed annual global mean temperatures for each year from 1980 to 2024 are shown relative to the pre-industrial global mean temperature (1850-1900) using an updated version of the IPCC AR6 report global mean temperature dataset through 2023, and the WMO estimate for 2024. The temperature forecast for 2025 is shown with a white dot for the central estimate, and white brackets showing the 95% confidence interval (the actual value is expected to be within this range 19 times out of 20).

Global mean temperatures are reported relative to a pre-industrial baseline. They represent the difference between the global mean temperature for a given year and the global mean temperature averaged over the 1850-1900 period, prior to most human-induced warming. The annual global mean temperature in 2025 is forecasted to be between 1.35 °C and 1.55 °C (with a central estimate of 1.45 °C) above the mean for the pre-industrial period (1850-1900). This will be the 12th consecutive year that temperatures have reached at least 1.0 °C above pre-industrial levels.

Both 2023 and 2024 were record-breaking warm years, reaching 1.43 °C and 1.55 °C above the pre-industrial period respectively. These unprecedented temperatures were driven by multiple factors, including unusually warm ocean waters and a strong El Niño event, compounded by the ongoing long-term trend of human-induced global warming. The record high temperatures in 2023 and 2024 were accompanied by heat waves across Canada attributed to climate change.

2024 was the warmest year on record, and the first year to exceed the 1.5 °C threshold established by the Paris Agreement. Exceeding this threshold in a single year does not constitute a breach of the agreement nor does it indicate that the long-term average of global mean surface temperatures has surpassed 1.5 °C. Although ECCC is forecasting only a 17% chance of exceeding the 1.5 °C threshold in 2025, their decadal forecasts indicate that the next five years are likely to be the warmest five-year period on record.

“Environment and Climate Change Canada’s seasonal forecasts provide regional climate outlooks out to 12 months for Canada and the globe, and also accurately predict average global temperatures for the coming year. The forecast for 2025 indicates that the extraordinary jump in global temperatures in 2023 and 2024 is here to stay, even without the influence of El Niño which boosted temperatures in those years.”

– ECCC scientist Dr. Bill Merryfield

Although the 2023-2024 El Niño has ended, the global mean temperature in 2025 is expected to surpass the earlier record set during the exceptionally strong 2014-2016 El Niño. Cool tropical Pacific temperatures meeting the criteria for a weak La Niña have been forecasted for early 2025, however any cooling influence they bring will be only a temporary fluctuation on top of the rapid warming driven by greenhouse gas emissions.

AGMT Figure 2

Evaluation of forecasts of past annual global mean temperature produced by CanSIPSv3 for 1980 to 2024. The central estimates of the forecasts are shown in red, with the shaded area indicating the 95% confidence interval. The observed annual global mean temperatures from 1980 to 2024 relative to the pre-industrial mean temperature for 1850-1900 are shown in black using an updated version of the dataset used in the IPCC AR6 report through 2023, and the WMO estimate for 2024.

The Environment and Climate Change Canada annual global mean temperature forecast is produced by the Canadian Centre for Climate Modelling and Analysis using the Canadian Seasonal to Interannual Prediction System version 3 (CanSIPSv3). These forecasts perform well when compared to observations over recent decades. Seasonal forecasts produced using CanSIPSv3 are issued monthly and will be available on ClimateData.ca later in 2025.