diff --git a/lib/matplotlib/axes.py b/lib/matplotlib/axes.py
index 1c10f2013d3f..8d078c22c1af 100644
--- a/lib/matplotlib/axes.py
+++ b/lib/matplotlib/axes.py
@@ -4728,7 +4728,7 @@ def pcolormesh(self, *args, **kwargs):
         X = X.ravel()
         Y = Y.ravel()
 
-        coords = npy.zeros(((Nx * Ny), 2), X.dtype)
+        coords = npy.zeros(((Nx * Ny), 2), dtype=float)
         coords[:, 0] = X
         coords[:, 1] = Y