diff --git a/utide/confidence.py b/utide/confidence.py
index 6ec8b1d..5cde5a5 100644
--- a/utide/confidence.py
+++ b/utide/confidence.py
@@ -252,7 +252,10 @@ def _confidence(coef, cnstit, opt, t, e, tin, elor, xraw, xmod, W, m, B,
             varcov_mCw[c, :2, :2] = Duu
 
             if not opt.white:
-                Duu = Puu[c] * Duu / np.trace(Duu)
+                Duu = Puu[c] * Duu
+                trace = np.trace(Duu)
+                if trace != 0.:
+                    Duu /= trace
                 varcov_mCc[c, :2, :2] = Duu
 
             if not opt.twodim:
diff --git a/utide/harmonics.py b/utide/harmonics.py
index 020d6d4..be75dbc 100644
--- a/utide/harmonics.py
+++ b/utide/harmonics.py
@@ -122,7 +122,9 @@ def FUV(t, tref, lind, lat, ngflgs):
 
         astro, ader = ut_astron(tt)
 
-        if abs(lat) < 5:
+        if lat == 0:
+            lat = 5
+        elif abs(lat) < 5:
             lat = np.sign(lat) * 5
 
         slat = np.sin(np.deg2rad(lat))