diff --git a/fv3/atmos_model.F90 b/fv3/atmos_model.F90
index 1d7a27498..24750db9d 100644
--- a/fv3/atmos_model.F90
+++ b/fv3/atmos_model.F90
@@ -978,6 +978,7 @@ subroutine update_atmos_model_state (Atmos, rc)
 !--- local variables
   integer :: i, localrc, sec_lastfhzerofh
   integer :: isec, seconds, isec_fhzero
+  integer :: dtatm_temp
   logical :: tmpflag_fhzero
   real(kind=GFS_kind_phys) :: time_int, time_intfull
 !
@@ -1012,9 +1013,10 @@ subroutine update_atmos_model_state (Atmos, rc)
       if (mpp_pe() == mpp_root_pe()) write(6,*) 'gfs diags time since last bucket empty: ',time_int,' time_intfull=', &
          time_intfull,' kdt=',GFS_control%kdt
       call atmosphere_nggps_diag(Atmos%Time)
+      call get_time ( Atmos%Time_step, dtatm_temp)
       call fv3atm_diag_output(Atmos%Time, GFS_Diag, Atm_block, GFS_control%nx, GFS_control%ny, &
                             GFS_control%levs, 1, 1, 1.0_GFS_kind_phys, time_int, time_intfull, &
-                            GFS_control%fhswr, GFS_control%fhlwr, GFS_control)
+                            GFS_control%fhswr, GFS_control%fhlwr, GFS_control, dtatm_temp)
     endif
 
     !---  find current fhzero
diff --git a/io/fv3atm_history_io.F90 b/io/fv3atm_history_io.F90
index a0f2fac4d..1ff4c14d3 100644
--- a/io/fv3atm_history_io.F90
+++ b/io/fv3atm_history_io.F90
@@ -115,13 +115,13 @@ end subroutine fv3atm_diag_register
   !! This routine transfers diagnostic data to the FMS diagnostic
   !!  manager for eventual output to the history files.
   subroutine fv3atm_diag_output(time, diag, atm_block, nx, ny, levs, ntcw, ntoz, &
-       dt, time_int, time_intfull, time_radsw, time_radlw, Model)
+       dt, time_int, time_intfull, time_radsw, time_radlw, Model, dt_atmos)
     !--- subroutine interface variable definitions
     type(time_type),           intent(in) :: time
     type(GFS_externaldiag_type),       intent(in) :: diag(:)
     type (block_control_type), intent(in) :: atm_block
     type(GFS_control_type),    intent(in) :: Model
-    integer,                   intent(in) :: nx, ny, levs, ntcw, ntoz
+    integer,                   intent(in) :: nx, ny, levs, ntcw, ntoz, dt_atmos
     real(kind=kind_phys),      intent(in) :: dt
     real(kind=kind_phys),      intent(in) :: time_int
     real(kind=kind_phys),      intent(in) :: time_intfull
@@ -129,7 +129,7 @@ subroutine fv3atm_diag_output(time, diag, atm_block, nx, ny, levs, ntcw, ntoz, &
     real(kind=kind_phys),      intent(in) :: time_radlw
 
     call shared_history_data%output(time, diag, atm_block, nx, ny, levs, ntcw, ntoz, &
-         dt, time_int, time_intfull, time_radsw, time_radlw, Model)
+         dt, time_int, time_intfull, time_radsw, time_radlw, Model, dt_atmos)
 
   end subroutine fv3atm_diag_output
 
@@ -282,14 +282,14 @@ end subroutine history_type_register
   !! implementation of the public fv3atm_diag_output routine. Never
   !! call this directly.
   subroutine history_type_output(hist, time, diag, atm_block, nx, ny, levs, ntcw, ntoz, &
-       dt, time_int, time_intfull, time_radsw, time_radlw, Model)
+       dt, time_int, time_intfull, time_radsw, time_radlw, Model, dt_atmos)
     !--- subroutine interface variable definitions
     class(history_type)                   :: hist
     type(time_type),           intent(in) :: time
     type(GFS_externaldiag_type),       intent(in) :: diag(:)
     type (block_control_type), intent(in) :: atm_block
     type(GFS_control_type),    intent(in) :: Model
-    integer,                   intent(in) :: nx, ny, levs, ntcw, ntoz
+    integer,                   intent(in) :: nx, ny, levs, ntcw, ntoz, dt_atmos
     real(kind=kind_phys),      intent(in) :: dt
     real(kind=kind_phys),      intent(in) :: time_int
     real(kind=kind_phys),      intent(in) :: time_intfull
@@ -310,8 +310,8 @@ subroutine history_type_output(hist, time, diag, atm_block, nx, ny, levs, ntcw,
 
     rtime_int     = one/time_int
     rtime_intfull = one/time_intfull
-    rtime_radsw   = one/time_radsw
-    rtime_radlw   = one/time_radlw
+    rtime_radsw   = one/(time_radsw * (int((time_int-dt_atmos)/time_radsw)+1))
+    rtime_radlw   = one/(time_radlw * (int((time_int-dt_atmos)/time_radlw)+1))
 
     !     if(mpp_pe()==mpp_root_pe())print *,'in,fv3atm_io. time avg, time_int=',time_int
     history_loop: do idx = 1,hist%tot_diag_idx
@@ -322,13 +322,13 @@ subroutine history_type_output(hist, time, diag, atm_block, nx, ny, levs, ntcw,
             lcnvfac = lcnvfac*rtime_intfull
             !             if(mpp_pe()==mpp_root_pe())print *,'in,fv3atm_io. full time avg, field=',trim(Diag(idx)%name),' time=',time_intfull
           else if ( trim(diag(idx)%time_avg_kind) == 'rad_lw' ) then
-            lcnvfac = lcnvfac*min(rtime_radlw,rtime_int)
+            lcnvfac = lcnvfac*rtime_radlw
             !             if(mpp_pe()==mpp_root_pe())print *,'in,fv3atm_io. rad longwave avg, field=',trim(Diag(idx)%name),' time=',time_radlw
           else if ( trim(diag(idx)%time_avg_kind) == 'rad_sw' ) then
-            lcnvfac = lcnvfac*min(rtime_radsw,rtime_int)
+            lcnvfac = lcnvfac*rtime_radsw
             !             if(mpp_pe()==mpp_root_pe())print *,'in,fv3atm_io. rad shortwave avg, field=',trim(Diag(idx)%name),' time=',time_radsw
           else if ( trim(diag(idx)%time_avg_kind) == 'rad_swlw_min' ) then
-            lcnvfac = lcnvfac*min(max(rtime_radsw,rtime_radlw),rtime_int)
+            lcnvfac = lcnvfac*max(rtime_radsw,rtime_radlw)
             !             if(mpp_pe()==mpp_root_pe())print *,'in,fv3atm_io. rad swlw min avg, field=',trim(Diag(idx)%name),' time=',time_radlw,time_radsw,time_int
           else
             lcnvfac = lcnvfac*rtime_int