diff --git a/astrobase/lcmath.py b/astrobase/lcmath.py
index <HASH>..<HASH> 100644
--- a/astrobase/lcmath.py
+++ b/astrobase/lcmath.py
@@ -1342,6 +1342,11 @@ def phase_bin_magseries_with_errs(phases, mags, errs,
         The minimum number of elements required per bin to include it in the
         output.
 
+    weights : np.array or None
+        Optional weight vector to be applied during binning. If if is passed,
+        `np.average` is used to bin, rather than `np.median`. A good choice
+        would be to pass weights=1/errs**2, to weight by the inverse variance.
+
     Returns
     -------
add weights kwarg to docstring