diff --git a/src/smallmap_gui.h b/src/smallmap_gui.h
--- a/src/smallmap_gui.h
+++ b/src/smallmap_gui.h
@@ -67,8 +67,8 @@ protected:
 
 	static const uint LEGEND_BLOB_WIDTH = 8;              ///< Width of the coloured blob in front of a line text in the #WID_SM_LEGEND widget.
 	static const uint INDUSTRY_MIN_NUMBER_OF_COLUMNS = 2; ///< Minimal number of columns in the #WID_SM_LEGEND widget for the #SMT_INDUSTRY legend.
-	static const uint FORCE_REFRESH_PERIOD = 0x1F; ///< map is redrawn after that many ticks
-	static const uint BLINK_PERIOD         = 0x0F; ///< highlight blinking interval
+	static const uint FORCE_REFRESH_PERIOD = 930; ///< map is redrawn after that many milliseconds.
+	static const uint BLINK_PERIOD         = 450; ///< highlight blinking interval in milliseconds.
 
 	uint min_number_of_columns;    ///< Minimal number of columns in legends.
 	uint min_number_of_fixed_rows; ///< Minimal number of rows in the legends for the fixed layouts only (all except #SMT_INDUSTRY).
@@ -79,7 +79,7 @@ protected:
 	int32 subscroll; ///< Number of pixels (0..3) between the right end of the base tile and the pixel at the top-left corner of the smallmap display.
 	int zoom;        ///< Zoom level. Bigger number means more zoom-out (further away).
 
-	uint8 refresh;   ///< Refresh counter, zeroed every FORCE_REFRESH_PERIOD ticks.
+	int refresh;     ///< Refresh timer, in millseconds.
 	LinkGraphOverlay *overlay;
 
 	static void BreakIndustryChainLink();
@@ -187,7 +187,7 @@ public:
 	virtual void OnInvalidateData(int data = 0, bool gui_scope = true);
 	virtual bool OnRightClick(Point pt, int widget);
 	virtual void OnMouseWheel(int wheel);
-	virtual void OnTick();
+	virtual void OnRealtimeTick(uint delta_ms);
 	virtual void OnScroll(Point delta);
 	virtual void OnMouseOver(Point pt, int widget);
 };