diff --git a/src/util/date.js b/src/util/date.js
index 102a64d..5c2ec47 100644
--- a/src/util/date.js
+++ b/src/util/date.js
@@ -9,7 +9,7 @@ const weekday = date => (date.getDay() + 6) % 7 + 1;
 
 const weekEpoch = new Date(1970, 0, -2); // monday before unix epoch in local timezone
 const weekOfEpoch = date =>
-  Math.abs(Math.floor((date - weekEpoch + (weekEpoch.getTimezoneOffset() - date.getTimezoneOffset()) * MINUTE) / WEEK));
+  Math.floor((date - weekEpoch + (weekEpoch.getTimezoneOffset() - date.getTimezoneOffset()) * MINUTE) / WEEK);
 
 function modify (date, unit, value) {
   switch (unit) {