diff --git a/core/divelist.c b/core/divelist.c
index 84290e6b6..94adc92dc 100644
--- a/core/divelist.c
+++ b/core/divelist.c
@@ -1420,3 +1420,32 @@ void sort_table(struct dive_table *table)
 {
 	qsort(table->dives, table->nr, sizeof(struct dive *), sortfn);
 }
+
+/*
+ * Calculate surface interval for dive starting at "when". Currently, we
+ * might display dives which are not yet in the divelist, therefore the
+ * input parameter is a timestamp.
+ * If the given dive starts during a different dive, the surface interval
+ * is 0. If we can't determine a surface interval (first dive), <0 is
+ * returned. This does *not* consider pathological cases such as dives
+ * that happened inside other dives. The interval will always be calculated
+ * with respect to the dive that started previously.
+ */
+timestamp_t get_surface_interval(timestamp_t when)
+{
+	int i;
+	timestamp_t prev_end;
+
+	/* find previous dive. might want to use a binary search. */
+	for (i = dive_table.nr - 1; i >= 0; --i) {
+		if (dive_table.dives[i]->when < when)
+			break;
+	}
+	if (i < 0)
+		return -1;
+
+	prev_end = dive_endtime(dive_table.dives[i]);
+	if (prev_end > when)
+		return 0;
+	return when - prev_end;
+}
diff --git a/core/divelist.h b/core/divelist.h
index 937909d2b..af47d0f23 100644
--- a/core/divelist.h
+++ b/core/divelist.h
@@ -42,6 +42,7 @@ extern struct dive *first_selected_dive();
 extern struct dive *last_selected_dive();
 extern bool is_trip_before_after(const struct dive *dive, bool before);
 extern void set_dive_nr_for_current_dive();
+extern timestamp_t get_surface_interval(timestamp_t when);
 
 int get_min_datafile_version();
 void reset_min_datafile_version();
diff --git a/core/statistics.c b/core/statistics.c
index beeb258a6..b25080a9f 100644
--- a/core/statistics.c
+++ b/core/statistics.c
@@ -3,7 +3,7 @@
  *
  * core logic for the Info & Stats page -
  * char *get_minutes(int seconds);
- * void process_all_dives(struct dive *dive, struct dive **prev_dive);
+ * void process_all_dives();
  */
 #include "gettext.h"
 #include <string.h>
@@ -91,7 +91,7 @@ char *get_minutes(int seconds)
 	return buf;
 }
 
-void process_all_dives(struct dive *dive, struct dive **prev_dive)
+void process_all_dives()
 {
 	int idx;
 	struct dive *dp;
@@ -105,7 +105,6 @@ void process_all_dives(struct dive *dive, struct dive **prev_dive)
 	dive_trip_t *trip_ptr = 0;
 	unsigned int size, tsize;
 
-	*prev_dive = NULL;
 	memset(&stats, 0, sizeof(stats));
 	if (dive_table.nr > 0) {
 		stats.shortest_time.seconds = dive_table.dives[0]->duration.seconds;
@@ -152,11 +151,6 @@ void process_all_dives(struct dive *dive, struct dive **prev_dive)
 	/* this relies on the fact that the dives in the dive_table
 	 * are in chronological order */
 	for_each_dive (idx, dp) {
-		if (dive && dp->when == dive->when) {
-			/* that's the one we are showing */
-			if (idx > 0)
-				*prev_dive = dive_table.dives[idx - 1];
-		}
 		process_dive(dp, &stats);
 
 		/* yearly statistics */
diff --git a/core/statistics.h b/core/statistics.h
index 597edfb94..7766d3154 100644
--- a/core/statistics.h
+++ b/core/statistics.h
@@ -48,7 +48,7 @@ extern stats_t *stats_by_trip;
 extern stats_t *stats_by_type;
 
 extern char *get_minutes(int seconds);
-extern void process_all_dives(struct dive *dive, struct dive **prev_dive);
+extern void process_all_dives();
 extern void get_gas_used(struct dive *dive, volume_t gases[MAX_CYLINDERS]);
 extern void process_selected_dives(void);
 void selected_dives_gas_parts(volume_t *o2_tot, volume_t *he_tot);
diff --git a/desktop-widgets/tab-widgets/TabDiveInformation.cpp b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
index a4f8f455f..aff781a3b 100644
--- a/desktop-widgets/tab-widgets/TabDiveInformation.cpp
+++ b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
@@ -77,12 +77,9 @@ void TabDiveInformation::updateData()
 	ui->diveTimeText->setText(get_dive_duration_string(displayed_dive.duration.seconds, tr("h"), tr("min"), tr("sec"),
 			" ", displayed_dive.dc.divemode == FREEDIVE));
 
-	struct dive *prevd;
-	process_all_dives(&displayed_dive, &prevd);
-
-	if (prevd)
-		ui->surfaceIntervalText->setText(get_dive_surfint_string(displayed_dive.when - (dive_endtime(prevd)), tr("d"), tr("h"), tr("min")));
-
+	timestamp_t surface_interval = get_surface_interval(displayed_dive.when);
+	if (surface_interval >= 0)
+		ui->surfaceIntervalText->setText(get_dive_surfint_string(surface_interval, tr("d"), tr("h"), tr("min")));
 	else
 		ui->surfaceIntervalText->clear();
 
diff --git a/desktop-widgets/tab-widgets/maintab.cpp b/desktop-widgets/tab-widgets/maintab.cpp
index eb8292b1a..ffcb70f5a 100644
--- a/desktop-widgets/tab-widgets/maintab.cpp
+++ b/desktop-widgets/tab-widgets/maintab.cpp
@@ -429,10 +429,8 @@ void MainTab::updateDiveInfo(bool clear)
 	// If exactly one trip has been selected, we show the location / notes
 	// for the trip in the Info tab, otherwise we show the info of the
 	// selected_dive
-	struct dive *prevd;
-
 	process_selected_dives();
-	process_all_dives(&displayed_dive, &prevd);
+	process_all_dives();
 
 	for (auto widget : extraWidgets) {
 		widget->updateData();
diff --git a/export-html.cpp b/export-html.cpp
index f66bd6909..fecbb5235 100644
--- a/export-html.cpp
+++ b/export-html.cpp
@@ -54,11 +54,7 @@ int main(int argc, char **argv)
 	prefs.units = git_prefs.units;
 
 	// populate the statistics
-	struct dive *d = get_dive(0);
-	struct dive *pd;
-	if (d) {
-		process_all_dives(d, &pd);
-	}
+	process_all_dives();
 
 	// now set up the export settings to create the HTML export
 	struct htmlExportSetting hes;