diff --git a/pysqm/plot.py b/pysqm/plot.py
index 8f127a23ec8f4aa7604f8d0b965ac7a232a28d9a..edd3033ee6beac6dc31530e8659fe7989ba4a891 100644
--- a/pysqm/plot.py
+++ b/pysqm/plot.py
@@ -590,7 +590,7 @@ class Plot(object):
         self.thegraph_sunalt.set_xlim([\
          config.limits_sunalt[0]*np.pi/180.,\
          config.limits_sunalt[1]*np.pi/180.])
-        self.thegraph_sunalt.set_ylim(config.limits_nsb)
+        if np.size(config.limits_nsb) == 2: self.thegraph_sunalt.set_ylim(config.limits_nsb)
 
         premidnight_label = str(Data.premidnight.label_dates).replace('[','').replace(']','')
         aftermidnight_label = str(Data.aftermidnight.label_dates).replace('[','').replace(']','')
@@ -671,7 +671,7 @@ class Plot(object):
             return(None)
 
         self.thegraph_time.set_xlim(begin_plot_dt,end_plot_dt)
-        self.thegraph_time.set_ylim(config.limits_nsb)
+        if np.size(config.limits_nsb) == 2: self.thegraph_time.set_ylim(config.limits_nsb)
 
         premidnight_label = str(Data.premidnight.label_dates).replace('[','').replace(']','')
         aftermidnight_label = str(Data.aftermidnight.label_dates).replace('[','').replace(']','')