diff --git a/src/core/MOM_boundary_update.F90 b/src/core/MOM_boundary_update.F90
index 5a098cdf84..75f69dc779 100644
--- a/src/core/MOM_boundary_update.F90
+++ b/src/core/MOM_boundary_update.F90
@@ -156,7 +156,7 @@ subroutine update_OBC_data(OBC, G, GV, US, tv, h, CS, Time)
       call shelfwave_set_OBC_data(OBC, CS%shelfwave_OBC_CSp, G, GV, US, h, Time)
   if (CS%use_dyed_channel) &
       call dyed_channel_update_flow(OBC, CS%dyed_channel_OBC_CSp, G, GV, US, Time)
-  if (OBC%needs_IO_for_data .or. OBC%add_tide_constituents)  &
+  if (OBC%any_needs_IO_for_data .or. OBC%add_tide_constituents)  &
       call update_OBC_segment_data(G, GV, US, OBC, tv, h, Time)
 
 end subroutine update_OBC_data
diff --git a/src/core/MOM_open_boundary.F90 b/src/core/MOM_open_boundary.F90
index d32e947da1..896a677b02 100644
--- a/src/core/MOM_open_boundary.F90
+++ b/src/core/MOM_open_boundary.F90
@@ -278,7 +278,9 @@ module MOM_open_boundary
   logical :: update_OBC = .false.                     !< Is OBC data time-dependent
   logical :: update_OBC_seg_data = .false.            !< Is it the time for OBC segment data update for fields that
                                                       !! require less frequent update
-  logical :: needs_IO_for_data = .false.              !< Is any i/o needed for OBCs
+  logical :: needs_IO_for_data = .false.              !< Is any i/o needed for OBCs on the current PE
+  logical :: any_needs_IO_for_data = .false.          !< Is any i/o needed for OBCs globally
+  logical :: some_need_no_IO_for_data = .false.       !< Are there any PEs with OBCs that do not need i/o.
   logical :: zero_vorticity = .false.                 !< If True, sets relative vorticity to zero on open boundaries.
   logical :: freeslip_vorticity = .false.             !< If True, sets normal gradient of tangential velocity to zero
                                                       !! in the relative vorticity on open boundaries.
@@ -736,6 +738,7 @@ subroutine initialize_segment_data(G, GV, US, OBC, PF)
   integer, dimension(1) :: single_pelist
   type(external_tracers_segments_props), pointer :: obgc_segments_props_list =>NULL()
   !will be able to dynamically switch between sub-sampling refined grid data or model grid
+  integer :: IO_needs(3) ! Sums to determine global OBC data use and update patterns.
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
 
@@ -1045,6 +1048,15 @@ subroutine initialize_segment_data(G, GV, US, OBC, PF)
 
   call Set_PElist(saved_pelist)
 
+  ! Determine global IO data requirement patterns.
+  IO_needs(1) = 0 ; if (OBC%needs_IO_for_data) IO_needs(1) = 1
+  IO_needs(2) = 0 ; if (OBC%update_OBC) IO_needs(2) = 1
+  IO_needs(3) = 0 ; if (.not.OBC%needs_IO_for_data) IO_needs(3) = 1
+  call sum_across_PES(IO_needs, 3)
+  OBC%any_needs_IO_for_data = (IO_needs(1) > 0)
+  OBC%update_OBC = (IO_needs(2) > 0)
+  OBC%some_need_no_IO_for_data = (IO_needs(3) > 0)
+
 end subroutine initialize_segment_data
 
 !> Return an appropriate dimensional scaling factor for input data based on an OBC segment data
@@ -1909,7 +1921,7 @@ logical function open_boundary_query(OBC, apply_open_OBC, apply_specified_OBC, a
                                                         OBC%Flather_v_BCs_exist_globally
   if (present(apply_nudged_OBC)) open_boundary_query = OBC%nudged_u_BCs_exist_globally .or. &
                                                        OBC%nudged_v_BCs_exist_globally
-  if (present(needs_ext_seg_data)) open_boundary_query = OBC%needs_IO_for_data
+  if (present(needs_ext_seg_data)) open_boundary_query = OBC%any_needs_IO_for_data
 
 end function open_boundary_query
 
@@ -5755,6 +5767,8 @@ subroutine rotate_OBC_config(OBC_in, G_in, OBC, G, turns)
   OBC%brushcutter_mode = OBC_in%brushcutter_mode
   OBC%update_OBC = OBC_in%update_OBC
   OBC%needs_IO_for_data = OBC_in%needs_IO_for_data
+  OBC%any_needs_IO_for_data = OBC_in%any_needs_IO_for_data
+  OBC%some_need_no_IO_for_data = OBC_in%some_need_no_IO_for_data
 
   OBC%ntr = OBC_in%ntr
 
diff --git a/src/initialization/MOM_state_initialization.F90 b/src/initialization/MOM_state_initialization.F90
index 69d59961ec..4bddc0965a 100644
--- a/src/initialization/MOM_state_initialization.F90
+++ b/src/initialization/MOM_state_initialization.F90
@@ -18,6 +18,7 @@ module MOM_state_initialization
 use MOM_get_input, only : directories
 use MOM_grid, only : ocean_grid_type, isPointInCell
 use MOM_interface_heights, only : find_eta, dz_to_thickness, dz_to_thickness_simple
+use MOM_interface_heights, only : calc_derived_thermo
 use MOM_io, only : file_exists, field_size, MOM_read_data, MOM_read_vector, slasher
 use MOM_open_boundary, only : ocean_OBC_type, open_boundary_init, set_tracer_data
 use MOM_open_boundary, only : OBC_NONE
@@ -607,8 +608,10 @@ subroutine MOM_initialize_state(u, v, h, tv, Time, G, GV, US, PF, dirs, &
     call initialize_segment_data(G, GV, US, OBC, PF)
 !     call open_boundary_config(G, US, PF, OBC)
     ! Call this once to fill boundary arrays from fixed values
-    if (.not. OBC%needs_IO_for_data)  &
+    if (OBC%some_need_no_IO_for_data) then
+      call calc_derived_thermo(tv, h, G, GV, US)
       call update_OBC_segment_data(G, GV, US, OBC, tv, h, Time)
+    endif
 
     call get_param(PF, mdl, "OBC_USER_CONFIG", config, &
                  "A string that sets how the user code is invoked to set open boundary data: \n"//&