Index: wflow-py/wflow/wf_netcdfio.py
===================================================================
diff -u -rc51d6ab8cffdf7a63dfa18fc4750728d29100ef9 -r836f5c634f2a0b397223c5fefd89df77e223b0e4
--- wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision c51d6ab8cffdf7a63dfa18fc4750728d29100ef9)
+++ wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision 836f5c634f2a0b397223c5fefd89df77e223b0e4)
@@ -335,10 +335,11 @@
         # timeObj = netCDF4.num2date(time[:], units=time.units, calendar=time.calendar)
 
         idx = timestep - 1
+        
+        buffreset = int((idx + 1) % self.maxbuf)
+        bufpos = int((idx) % self.maxbuf)
+                
 
-        buffreset = (idx + 1) % self.maxbuf
-        bufpos = (idx) % self.maxbuf
-
         try:
             nc_var = self.nc_trg.variables[var]
         except: