Zeke Hausfather in Climate Brink:
While global temperature records are not yet in for the full month of October 2023, real-time reanalysis products increasingly allow scientists to track global temperatures on a daily basis.
Reanalysis pulls together a huge amount of data from satellites, weather balloons, aeroplanes, weather stations, ships and buoys to provide a detailed look at how the Earth’s climate is changing in real-time.
Modern reanalysis products, such as JRA-55 and ERA5, use state-of-the-art methods to produce records that align well with traditional surface temperature datasets over recent decades.
The figure (above) shows the daily global temperature anomaly values from the JRA-55 reanalysis product for each day since the record began in 1958 (grey lines). It shows the current year to date (2023) in red and the prior record warm year, 2016, in blue. Nearly every single day since mid-June 2023 has been warmer than any prior days since the JRA-55 record began in 1958 – and, potentially, much further into the past.
Look at Zeke’s detailed article in Carbon Brief, not just the summary linked here. It contains all the useful graphs. A link to the details is located in the summary article.