Add support for freshly downloaded ERA5 hourly data (#3087)

Author: schlunma

esmvalcore/cmor/_fixes/native6/era5.py

@@ -33,7 +33,9 @@ def fix_hourly_time_coordinate(cube, frequency):
     # variables from ERA5 may lead to some differences.
     if frequency.startswith("1hr"):
         time = cube.coord(axis="T")
-        if str(time.units).startswith("hours since"):
+        if str(time.units).startswith("seconds since"):
+            shift = 1800.0
+        elif str(time.units).startswith("hours since"):
             shift = 0.5
         elif str(time.units).startswith("days since"):
             shift = 1.0 / 48.0

tests/integration/cmor/_fixes/native6/test_era5.py

@@ -408,6 +408,8 @@ def evspsbl_era5_hourly():
             (_era5_longitude(), 2),
         ],
     )
+    # Test time units of newly downloaded ERA5 data (2026-05-20)
+    cube.coord("time").convert_units("seconds since 1970-01-01")
     return CubeList([cube])