diff --git a/Source/ERF.H b/Source/ERF.H
index 08bc5eb4f..125e6282f 100644
--- a/Source/ERF.H
+++ b/Source/ERF.H
@@ -707,7 +707,7 @@ private:
     void setSpongeRefFromSounding (bool restarting);
 
     // a wrapper for estTimeStep()
-    void ComputeDt (int step = -1);
+    void ComputeDt (int step = -1, double cur_time_d = 0.0);
 
     // get plotfile name
     [[nodiscard]] std::string PlotFileName (int lev) const;
diff --git a/Source/ERF.cpp b/Source/ERF.cpp
index 6016ad726..2d1565fe4 100644
--- a/Source/ERF.cpp
+++ b/Source/ERF.cpp
@@ -609,8 +609,8 @@ ERF::Evolve ()
     //
     // cur_time = t_new is elapsed time, not total time
     // stop_time is total time
-    //
-    Real cur_time = t_new[0];
+    // Tracked in double to avoid float32 drift over many timesteps in single-precision builds.
+    double cur_time = static_cast<double>(t_new[0]);
 
     // Take one coarse timestep by calling timeStep -- which recursively calls timeStep
     //      for finer levels (with or without subcycling)
@@ -622,7 +622,7 @@ ERF::Evolve ()
         }
         Print() << "\nCoarse STEP " << step+1 << " starts ..." << std::endl;
 
-        ComputeDt(step);
+        ComputeDt(step, cur_time);
 
         // Make sure we have read enough of the boundary plane data to make it through this timestep
         if (input_bndry_planes)
@@ -657,7 +657,9 @@ ERF::Evolve ()
         int iteration = 1;
         timeStep(0, cur_time, iteration);
 
-        cur_time  += dt[0];
+        cur_time += static_cast<double>(dt[0]);
+        // Sync t_new[0] from accurate double to prevent float32 accumulation drift in SP builds.
+        t_new[0] = static_cast<Real>(cur_time);
 
         Print() << "Coarse STEP " << step+1 << " ends." << " TIME = " << cur_time
                 << " DT = " << dt[0]  << std::endl;
diff --git a/Source/TimeIntegration/ERF_ComputeTimestep.cpp b/Source/TimeIntegration/ERF_ComputeTimestep.cpp
index 9c3e1b06c..5cf40753a 100644
--- a/Source/TimeIntegration/ERF_ComputeTimestep.cpp
+++ b/Source/TimeIntegration/ERF_ComputeTimestep.cpp
@@ -8,7 +8,7 @@ using namespace amrex;
  *
  */
 void
-ERF::ComputeDt (int step)
+ERF::ComputeDt (int step, double cur_time_d)
 {
     Vector<Real> dt_tmp(finest_level+1);
 
@@ -40,8 +40,8 @@ ERF::ComputeDt (int step)
     //     so we must add start_time to t_new
     //
     const Real eps = Real(1.e-3)*dt_0;
-    if (t_new[0] + dt_0 > (stop_time - start_time) - eps) {
-        dt_0 = (stop_time - start_time) - t_new[0];
+    if (cur_time_d + static_cast<double>(dt_0) > static_cast<double>(stop_time - start_time) - static_cast<double>(eps)) {
+        dt_0 = static_cast<Real>(static_cast<double>(stop_time - start_time) - cur_time_d);
     }
 
     dt[0] = dt_0;