Start at month 1 of year

da/preprocessing/era5.py

@@ -132,7 +132,7 @@ def check_era_present(dacycle):
     NRUNYEARS_SPINUP = int(dacycle.dasystem['sib.spinup.years'])
 
     # SiB runs start 'NRUNYEARS_SPINUP'  years beforehand, on the first of the month
-    sib_starttime = dtm.datetime(starttime.year - NRUNYEARS_SPINUP, starttime.month, 1)
+    sib_starttime = dtm.datetime(starttime.year - NRUNYEARS_SPINUP, 1, 1)
     # SiB ends on the final day of the last month in the dasystem
     sib_endtime = dtm.datetime(endtime.year, endtime.month + 1, 1) - dtm.timedelta(days=1)