So far we have:
January - warmest on record. NOAA, Copernicus
February - 2nd warmest on record. NOAA, Copernicus
March - 2nd warmest on record. NOAA, Copernicus
April - no information by NOAA yet. Reported as being 0.01 degrees behind warmest by Copernicus
If NOAAs verdict is unavailable for some reason EU Copernicus Climate Monitoring is to be used instead for that month.