More than 20-years ago, I started calculating global temperature anomaly on daily (and 6-hourly) time scales with numerical weather prediction model data -- a pioneer in some regards -- but it eventually caught on! I just didn't trust the surface temperature record without the data assimilation constraints.
Some did not like the methodology, but it's now standard across globe -- at least for monthly averages.
I like the higher-frequency data in order to show the dependence of global temperature on weather time scale features (synoptic scale) especially since we're talking about 2-meters above ground, and not sea-surface temperatures.
ERA5 and JRA-3Q are the two 5th Generation NWP Reanalysis commonly used.
Here's 2009-2026 (as of 3-days ago)
Like a stock ticker 📈or heart EKG♥️we can take the daily pulse of the planet.
Global temperatures until the El Niño of Summer 2023 were not rising very much hovering around 0.2°C over 1991-2020 climatology (add 0.85°C for pre-industrial) so 1.05ºC. But the spike in summer 2023 was dramatic, and we've slowly planed off from the record high 365-day mean (red line) reached in mid-2024.
Is this evidence of "accelerated warming" ?
I don't think so BUT this ongoing El Niño is the true test the next 1-2 years.
Global warming happens in steps -- are we going to step up again?
Daily temperature analysis shows this much better than monthly.