diff --git a/arbor/backends/gpu/shared_state.hpp b/arbor/backends/gpu/shared_state.hpp
index 2f9c89cfde..31656c99be 100644
--- a/arbor/backends/gpu/shared_state.hpp
+++ b/arbor/backends/gpu/shared_state.hpp
@@ -143,9 +143,9 @@ struct ARB_ARBOR_API shared_state: shared_state_base<shared_state, array, ion_st
     arb_size_type n_cv = 0;       // Total number of CVs.
 
     iarray cv_to_cell;            // Maps CV index to cell index.
-    arb_value_type time;          // integration start time [ms].
-    arb_value_type time_to;       // integration end time [ms]
-    arb_value_type dt;            // dt [ms].
+    arb_value_type time = 0.0;    // integration start time [ms].
+    arb_value_type time_to = 0.0; // integration end time [ms]
+    arb_value_type dt  = 0.0;     // dt [ms].
     array voltage;                // Maps CV index to membrane voltage [mV].
     array current_density;        // Maps CV index to current density [A/m²].
     array conductivity;           // Maps CV index to membrane conductivity [kS/m²].
diff --git a/arbor/backends/multicore/shared_state.hpp b/arbor/backends/multicore/shared_state.hpp
index 6d0d49c804..3a4a97a9e7 100644
--- a/arbor/backends/multicore/shared_state.hpp
+++ b/arbor/backends/multicore/shared_state.hpp
@@ -152,9 +152,9 @@ struct ARB_ARBOR_API shared_state:
     arb_size_type n_cv = 0;         // Total number of CVs.
 
     iarray cv_to_cell;              // Maps CV index to GID
-    arb_value_type time;            // integration start time [ms].
-    arb_value_type time_to;         // integration end time [ms]
-    arb_value_type dt;              // dt [ms].
+    arb_value_type time = 0.0;      // integration start time [ms].
+    arb_value_type time_to = 0.0;   // integration end time [ms]
+    arb_value_type dt = 0.0;        // dt [ms].
     array voltage;                  // Maps CV index to membrane voltage [mV].
     array current_density;          // Maps CV index to membrane current density contributions [A/m²].
     array conductivity;             // Maps CV index to membrane conductivity [kS/m²].