diff --git a/nummi/history/templates/history/plot.html b/nummi/history/templates/history/plot.html
index fdc756d..8501506 100644
--- a/nummi/history/templates/history/plot.html
+++ b/nummi/history/templates/history/plot.html
@@ -60,7 +60,8 @@
                         {% endif %}
                         {% if m %}
                             <td class="{% if m.sum > 0 %}p{% else %}m{% endif %}"
-                                style="opacity: {% calendar_opacity m.sum history.max.sum %}"></td>
+                                style="opacity: {% calendar_opacity m.sum history.max.sum %}"
+                                title="{{ m.sum|pmrvalue }}"></td>
                         {% else %}
                             <td></td>
                         {% endif %}