From variable 3.3
Summary of observation-based historical datasets with 2-m temperature available

data type
Global atmospheric reanalysis
spatial domain
spatial resolution
0.25°  x 0.25°
temporal coverage
1950 to present
time step
Hourly; Daily; Monthly
data format
5th generation reanalysis. Assimilates surface temperature from stations separately from the atmospheric analysis component using a univariate 2-dimensional optimal interpolation (2D-OI). In ERA5, hourly 2 m temperature is an instantaneous parameter provided at hourly time step from the analysis. Monthly data is pre-calculated as monthly-mean averages from hourly data. Minimum and maximum temperature at 2 metres since previous post-processing are available from the forecasts only. However, ERA5 forecast model has a cold bias in the lower regions of the troposphere over most parts over the globe, which is partially corrected by the analysis system. It is therefore recommended to use the instantaneous hourly (analyzed) 2 m temperature to construct the minimum and maximum over longer periods, such as Tmin and Tmax.