diff --git a/src/Network/AWS/Wolf/Act.hs b/src/Network/AWS/Wolf/Act.hs
--- a/src/Network/AWS/Wolf/Act.hs
+++ b/src/Network/AWS/Wolf/Act.hs
@@ -70,7 +70,7 @@
         (token, uid, input) <- pollActivity
         t1 <- liftIO getCurrentTime
         statsCount "wolf.act.poll.count" (1 :: Int) [ "queue" =. queue ]
-        statsHistogram "wolf.act.poll.elapsed" (diffUTCTime t1 t0) [ "queue" =. queue ]
+        statsHistogram "wolf.act.poll.elapsed" (realToFrac (diffUTCTime t1 t0) :: Double) [ "queue" =. queue ]
         maybe_ token $ \token' ->
           maybe_ uid $ \uid' ->
             withCurrentWorkDirectory uid' $ \wd ->
@@ -92,7 +92,7 @@
                 traceInfo "finish" [ "output" .= output ]
                 let status = textFromString $ maybe "complete" (const "fail") e
                 statsCount "wolf.act.activity.count" (1 :: Int) [ "queue" =. queue, "status" =. status ]
-                statsHistogram "wolf.act.activity.elapsed" (diffUTCTime t3 t2) [ "queue" =. queue ]
+                statsHistogram "wolf.act.activity.elapsed" (realToFrac (diffUTCTime t3 t2) :: Double) [ "queue" =. queue ]
 
 
 -- | Run actor from main with config file.
diff --git a/src/Network/AWS/Wolf/Decide.hs b/src/Network/AWS/Wolf/Decide.hs
--- a/src/Network/AWS/Wolf/Decide.hs
+++ b/src/Network/AWS/Wolf/Decide.hs
@@ -97,7 +97,7 @@
         (token, hes) <- pollDecision
         t1 <- liftIO getCurrentTime
         statsCount "wolf.decide.poll.count" (1 :: Int) [ "queue" =. queue ]
-        statsHistogram "wolf.decide.poll.elapsed" (diffUTCTime t1 t0) [ "queue" =. queue ]
+        statsHistogram "wolf.decide.poll.elapsed" (realToFrac (diffUTCTime t1 t0) :: Double) [ "queue" =. queue ]
         maybe_ token $ \token' ->
           runAmazonDecisionCtx p hes $ do
             traceInfo "start" mempty
@@ -107,7 +107,7 @@
             t3 <- liftIO getCurrentTime
             traceInfo "finish" mempty
             statsCount "wolf.decide.decision.count" (1 :: Int) [ "queue" =. queue ]
-            statsHistogram "wolf.decide.decision.elapsed" (diffUTCTime t3 t2) [ "queue" =. queue ]
+            statsHistogram "wolf.decide.decision.elapsed" (realToFrac (diffUTCTime t3 t2) :: Double) [ "queue" =. queue ]
 
 -- | Run decider from main with config file.
 --
diff --git a/wolf.cabal b/wolf.cabal
--- a/wolf.cabal
+++ b/wolf.cabal
@@ -1,5 +1,5 @@
 name:                  wolf
-version:               0.3.11
+version:               0.3.12
 synopsis:              Amazon Simple Workflow Service Wrapper.
 description:           Wolf is a wrapper around Amazon Simple Workflow Service.
 homepage:              https://github.com/swift-nav/wolf