diff -up ./panel-plugin/weather.c.orig ./panel-plugin/weather.c
--- ./panel-plugin/weather.c.orig	2019-08-26 22:58:28.946952320 +0300
+++ ./panel-plugin/weather.c	2019-08-26 23:13:14.986917277 +0300
@@ -100,6 +100,9 @@ static void write_cache_file(plugin_data
 
 static void schedule_next_wakeup(plugin_data *data);
 
+void sigusr1_handler(int sig);
+
+gboolean sigusr1_summary(plugin_data *user_data);
 
 void
 weather_http_queue_request(SoupSession *session,
@@ -948,6 +951,9 @@ xfceweather_read_config(XfcePanelPlugin
             g_array_append_val(data->labels, val);
     }
 
+    /* Whether we show summary window on SIGUSR1 */
+    data->sigusr1_summary = xfce_rc_read_bool_entry(rc, "sigusr1_summary", FALSE);
+
     xfce_rc_close(rc);
     weather_debug("Config file read.");
 }
@@ -1043,6 +1049,9 @@ xfceweather_write_config(XfcePanelPlugin
                                                      data_types, i));
     }
 
+    /* Whether we show summary window on SIGUSR1 */
+    xfce_rc_write_bool_entry(rc, "sigusr1_summary", data->sigusr1_summary);
+
     xfce_rc_close(rc);
     weather_debug("Config file written.");
 }
@@ -2257,6 +2266,34 @@ weather_construct(XfcePanelPlugin *plugi
 #endif /* HAVE_UPOWER_GLIB */
 
     weather_dump(weather_dump_plugindata, data);
+
+#ifdef GLIB_VERSION_2_36
+    g_unix_signal_add(SIGUSR1, sigusr1_summary, data);
+#else
+    g_warning(_("glib2 >= 2.36 is required for SIGUSR1 handling"));
+#endif
 }
 
+#ifdef GLIB_VERSION_2_36
+gboolean
+sigusr1_summary(plugin_data *data)
+{
+    if (data->sigusr1_summary) {
+        /* This seems to do nothing at all. What's wrong? */
+        /*
+           gboolean ret;
+           g_signal_emit_by_name(GTK_TOGGLE_BUTTON (data->button), "button-press-event", data, &ret);
+        */
+        /* Neither does this. Giving up */
+        /*
+           gboolean ret;
+           g_signal_emit_by_name(GTK_WIDGET (data->plugin), "button-press-event", data, &ret);
+        */
+        /* This works but panel button does not appear as pressed */
+        forecast_click(GTK_WIDGET(data->plugin), data);
+    }
+    return G_SOURCE_CONTINUE;
+}
+#endif
+
 XFCE_PANEL_PLUGIN_REGISTER(weather_construct)
diff -up ./panel-plugin/weather.h.orig ./panel-plugin/weather.h
--- ./panel-plugin/weather.h.orig	2019-08-26 22:58:28.946952320 +0300
+++ ./panel-plugin/weather.h	2019-08-26 23:13:14.986917277 +0300
@@ -127,6 +127,7 @@ typedef struct {
     forecast_layouts forecast_layout;
     guint forecast_days;
     gboolean round;
+    gboolean sigusr1_summary; /* Whether we show summary window on SIGUSR1 */
 } plugin_data;