Request data for previus years but get last 365 days

I try to download temperature data from 2025 with the following code

{

        "product_type": ["reanalysis"],

        "variable": ["2m_temperature"],

        "year": ["2025"],

        "grid": [

        0.1,

        0.1

      ],

        "month": [

            "01", "02", "03",

            "04", "05", "06",

            "07", "08", "09",

            "10", "11", "12"

        ],

        "day": [

            "01", "02", "03",

            "04", "05", "06",

            "07", "08", "09",

            "10", "11", "12",

            "13", "14", "15",

            "16", "17", "18",

            "19", "20", "21",

            "22", "23", "24",

            "25", "26", "27",

            "28", "29", "30",

            "31"

        ],

        "time": [

            "00:00", "01:00", "02:00",

            "03:00", "04:00", "05:00",

            "06:00", "07:00", "08:00",

            "09:00", "10:00", "11:00",

            "12:00", "13:00", "14:00",

            "15:00", "16:00", "17:00",

            "18:00", "19:00", "20:00",

            "21:00", "22:00", "23:00"

        ],

        "data_format": "grib",

        "download_format": "unarchived",

        "area": [69, 11, 54, 24]

    }

I the convert the grib file to a NetCDF file with gdal.warp in python

The I try to create daily mean and max for each day of the year. Here I noticed that I dont get data from 2025 but from today and one year back.

timestamps = []
for band in ds.data_vars:
    if "GRIB_REF_TIME" in ds[band].attrs:
        timestamps.append(ds[band].attrs["GRIB_REF_TIME"])

# Convert timestamps from UNIX time (seconds since epoch) to datetime
timestamps = pd.to_datetime(timestamps, unit="s")

My timestamp then contains data from the current year

print(timestamps[:100])

DatetimeIndex([‘2026-01-01 00:00:00’, ‘2026-01-01 01:00:00’,
‘2026-01-01 02:00:00’, ‘2026-01-01 03:00:00’,
‘2026-01-01 04:00:00’, ‘2026-01-01 05:00:00’,
‘2026-01-01 06:00:00’, ‘2026-01-01 07:00:00’,
‘2026-01-01 08:00:00’, ‘2026-01-01 09:00:00’,
‘2026-01-01 10:00:00’, ‘2026-01-01 11:00:00’,
‘2026-01-01 12:00:00’, ‘2026-01-01 13:00:00’,
‘2026-01-01 14:00:00’, ‘2026-01-01 15:00:00’,
‘2026-01-01 16:00:00’, ‘2026-01-01 17:00:00’,
‘2026-01-01 18:00:00’, ‘2026-01-01 19:00:00’,
‘2026-01-01 20:00:00’, ‘2026-01-01 21:00:00’,
‘2026-01-01 22:00:00’, ‘2026-01-01 23:00:00’,
‘2026-01-02 00:00:00’, ‘2026-01-02 01:00:00’,
‘2026-01-02 02:00:00’, ‘2026-01-02 03:00:00’,
‘2026-01-02 04:00:00’, ‘2026-01-02 05:00:00’,
‘2026-01-02 06:00:00’, ‘2026-01-02 07:00:00’,
‘2026-01-02 08:00:00’, ‘2026-01-02 09:00:00’,
‘2026-01-02 10:00:00’, ‘2026-01-02 11:00:00’,
‘2026-01-02 12:00:00’, ‘2026-01-02 13:00:00’,
‘2026-01-02 14:00:00’, ‘2026-01-02 15:00:00’,
‘2026-01-02 16:00:00’, ‘2026-01-02 17:00:00’,
‘2026-01-02 18:00:00’, ‘2026-01-02 19:00:00’,
‘2026-01-02 20:00:00’, ‘2026-01-02 21:00:00’,
‘2026-01-02 22:00:00’, ‘2026-01-02 23:00:00’,
‘2026-01-03 00:00:00’, ‘2026-01-03 01:00:00’,
‘2026-01-03 02:00:00’, ‘2026-01-03 03:00:00’,
‘2026-01-03 04:00:00’, ‘2026-01-03 05:00:00’,
‘2026-01-03 06:00:00’, ‘2026-01-03 07:00:00’,
‘2026-01-03 08:00:00’, ‘2026-01-03 09:00:00’,
‘2026-01-03 10:00:00’, ‘2026-01-03 11:00:00’,
‘2026-01-03 12:00:00’, ‘2026-01-03 13:00:00’,
‘2026-01-03 14:00:00’, ‘2026-01-03 15:00:00’,
‘2026-01-03 16:00:00’, ‘2026-01-03 17:00:00’,
‘2026-01-03 18:00:00’, ‘2026-01-03 19:00:00’,
‘2026-01-03 20:00:00’, ‘2026-01-03 21:00:00’,
‘2026-01-03 22:00:00’, ‘2026-01-03 23:00:00’,
‘2026-01-04 00:00:00’, ‘2026-01-04 01:00:00’,
‘2026-01-04 02:00:00’, ‘2026-01-04 03:00:00’,
‘2026-01-04 04:00:00’, ‘2026-01-04 05:00:00’,
‘2026-01-04 06:00:00’, ‘2026-01-04 07:00:00’,
‘2026-01-04 08:00:00’, ‘2026-01-04 09:00:00’,
‘2026-01-04 10:00:00’, ‘2026-01-04 11:00:00’,
‘2026-01-04 12:00:00’, ‘2026-01-04 13:00:00’,
‘2026-01-04 14:00:00’, ‘2026-01-04 15:00:00’,
‘2026-01-04 16:00:00’, ‘2026-01-04 17:00:00’,
‘2026-01-04 18:00:00’, ‘2026-01-04 19:00:00’,
‘2026-01-04 20:00:00’, ‘2026-01-04 21:00:00’,
‘2026-01-04 22:00:00’, ‘2026-01-04 23:00:00’,
‘2026-01-05 00:00:00’, ‘2026-01-05 01:00:00’,
‘2026-01-05 02:00:00’, ‘2026-01-05 03:00:00’],
dtype=‘datetime64[ns]’, freq=None)

Any suggestions what might be wrong? I see that there was a service window yesterday on CDS. Was there any API upgrades that might break my settings?

I managed to get the correct data.
The only change from previus is that I changed the download path in
client.retrieve(‘reanalysis-era5-single-levels’,‘request, 2025_1,grib’)
Don’t know if the output name is used retrieved from a cached old version. I’ve deleted it many times.

Hi,
please have a look at this: How to avoid the CDS cache issue

Thanks

Thanks four you help. Have looked into that now.