diff --git a/provider/mesh/peer_test.go b/provider/mesh/peer_test.go
index e39f5829..33b502a8 100644
--- a/provider/mesh/peer_test.go
+++ b/provider/mesh/peer_test.go
@@ -17,8 +17,7 @@ import (
 
 func TestNotificationInfosOnGossip(t *testing.T) {
 	var (
-		t0 = time.Now()
-		t1 = t0.Add(time.Minute)
+		now = utcNow()
 	)
 	cases := []struct {
 		initial map[string]notificationEntry
@@ -29,37 +28,37 @@ func TestNotificationInfosOnGossip(t *testing.T) {
 		{
 			initial: map[string]notificationEntry{},
 			msg: map[string]notificationEntry{
-				"123:recv1": {true, t0},
+				"123:recv1": {true, now},
 			},
 			delta: map[string]notificationEntry{
-				"123:recv1": {true, t0},
+				"123:recv1": {true, now},
 			},
 			final: map[string]notificationEntry{
-				"123:recv1": {true, t0},
+				"123:recv1": {true, now},
 			},
 		}, {
 			initial: map[string]notificationEntry{
-				"123:recv1": {true, t0},
+				"123:recv1": {true, now},
 			},
 			msg: map[string]notificationEntry{
-				"123:recv1": {false, t1},
+				"123:recv1": {false, now.Add(time.Minute)},
 			},
 			delta: map[string]notificationEntry{
-				"123:recv1": {false, t1},
+				"123:recv1": {false, now.Add(time.Minute)},
 			},
 			final: map[string]notificationEntry{
-				"123:recv1": {false, t1},
+				"123:recv1": {false, now.Add(time.Minute)},
 			},
 		}, {
 			initial: map[string]notificationEntry{
-				"123:recv1": {true, t1},
+				"123:recv1": {true, now.Add(time.Minute)},
 			},
 			msg: map[string]notificationEntry{
-				"123:recv1": {false, t0},
+				"123:recv1": {false, now},
 			},
 			delta: map[string]notificationEntry{},
 			final: map[string]notificationEntry{
-				"123:recv1": {true, t1},
+				"123:recv1": {true, now.Add(time.Minute)},
 			},
 		},
 	}
@@ -146,10 +145,7 @@ func TestNotificationInfosOnGossip(t *testing.T) {
 
 func TestNotificationInfosSet(t *testing.T) {
 	var (
-		t0 = time.Now()
-		t1 = t0.Add(10 * time.Minute)
-		// t2 = t0.Add(20 * time.Minute)
-		// t3 = t0.Add(30 * time.Minute)
+		now = utcNow()
 	)
 	cases := []struct {
 		initial map[string]notificationEntry
@@ -164,14 +160,14 @@ func TestNotificationInfosSet(t *testing.T) {
 					Alert:     0x10,
 					Receiver:  "recv1",
 					Resolved:  false,
-					Timestamp: t0,
+					Timestamp: now,
 				},
 			},
 			update: map[string]notificationEntry{
-				"0000000000000010:recv1": {false, t0},
+				"0000000000000010:recv1": {false, now},
 			},
 			final: map[string]notificationEntry{
-				"0000000000000010:recv1": {false, t0},
+				"0000000000000010:recv1": {false, now},
 			},
 		},
 		{
@@ -181,38 +177,38 @@ func TestNotificationInfosSet(t *testing.T) {
 			// The update is okay to propagate but the final state must correctly
 			// drop it.
 			initial: map[string]notificationEntry{
-				"0000000000000010:recv1": {false, t0},
-				"0000000000000010:recv2": {false, t1},
+				"0000000000000010:recv1": {false, now},
+				"0000000000000010:recv2": {false, now.Add(10 * time.Minute)},
 			},
 			input: []*types.NotifyInfo{
 				{
 					Alert:     0x10,
 					Receiver:  "recv1",
 					Resolved:  true,
-					Timestamp: t1,
+					Timestamp: now.Add(10 * time.Minute),
 				},
 				{
 					Alert:     0x10,
 					Receiver:  "recv2",
 					Resolved:  true,
-					Timestamp: t0,
+					Timestamp: now,
 				},
 				{
 					Alert:     0x20,
 					Receiver:  "recv2",
 					Resolved:  false,
-					Timestamp: t0,
+					Timestamp: now,
 				},
 			},
 			update: map[string]notificationEntry{
-				"0000000000000010:recv1": {true, t1},
-				"0000000000000010:recv2": {true, t0},
-				"0000000000000020:recv2": {false, t0},
+				"0000000000000010:recv1": {true, now.Add(10 * time.Minute)},
+				"0000000000000010:recv2": {true, now},
+				"0000000000000020:recv2": {false, now},
 			},
 			final: map[string]notificationEntry{
-				"0000000000000010:recv1": {true, t1},
-				"0000000000000010:recv2": {false, t1},
-				"0000000000000020:recv2": {false, t0},
+				"0000000000000010:recv1": {true, now.Add(10 * time.Minute)},
+				"0000000000000010:recv2": {false, now.Add(10 * time.Minute)},
+				"0000000000000020:recv2": {false, now},
 			},
 		},
 	}
@@ -243,8 +239,7 @@ func TestNotificationInfosSet(t *testing.T) {
 
 func TestNotificationInfosGet(t *testing.T) {
 	var (
-		t0 = time.Now()
-		t1 = t0.Add(time.Minute)
+		now = utcNow()
 	)
 	type query struct {
 		recv string
@@ -257,10 +252,10 @@ func TestNotificationInfosGet(t *testing.T) {
 	}{
 		{
 			state: map[string]notificationEntry{
-				"0000000000000010:recv1": {true, t1},
-				"0000000000000030:recv1": {true, t1},
-				"0000000000000010:recv2": {false, t1},
-				"0000000000000020:recv2": {false, t0},
+				"0000000000000010:recv1": {true, now.Add(time.Minute)},
+				"0000000000000030:recv1": {true, now.Add(time.Minute)},
+				"0000000000000010:recv2": {false, now.Add(time.Minute)},
+				"0000000000000020:recv2": {false, now},
 			},
 			queries: []query{
 				{
@@ -272,7 +267,7 @@ func TestNotificationInfosGet(t *testing.T) {
 							Alert:     0x10,
 							Receiver:  "recv1",
 							Resolved:  true,
-							Timestamp: t1,
+							Timestamp: now.Add(time.Minute),
 						},
 						nil,
 					},
@@ -303,7 +298,7 @@ func TestNotificationInfosGet(t *testing.T) {
 
 func TestSilencesSet(t *testing.T) {
 	var (
-		now      = time.Now()
+		now      = utcNow()
 		id1      = uuid.NewV4()
 		matchers = types.NewMatchers(types.NewMatcher("a", "b"))
 	)
diff --git a/provider/mesh/state.go b/provider/mesh/state.go
index f6bce70c..d80017fe 100644
--- a/provider/mesh/state.go
+++ b/provider/mesh/state.go
@@ -13,6 +13,8 @@ import (
 	"github.com/weaveworks/mesh"
 )
 
+func utcNow() time.Time { return time.Now().UTC() }
+
 type notificationEntry struct {
 	Resolved  bool
 	Timestamp time.Time
@@ -31,7 +33,7 @@ func newNotificationState() *notificationState {
 	return &notificationState{
 		set:   map[string]notificationEntry{},
 		stopc: make(chan struct{}),
-		now:   time.Now,
+		now:   utcNow,
 	}
 }
 
@@ -146,7 +148,7 @@ func newSilenceState() *silenceState {
 	return &silenceState{
 		m:     map[uuid.UUID]*types.Silence{},
 		stopc: make(chan struct{}),
-		now:   time.Now,
+		now:   utcNow,
 	}
 }
 
@@ -235,6 +237,9 @@ func (st *silenceState) set(s *types.Silence) error {
 	st.mtx.Lock()
 	defer st.mtx.Unlock()
 
+	s.StartsAt = s.StartsAt.UTC()
+	s.EndsAt = s.EndsAt.UTC()
+
 	now := st.now()
 	s.UpdatedAt = now
 
diff --git a/provider/mesh/state_test.go b/provider/mesh/state_test.go
index 852e6f27..28c4fc8d 100644
--- a/provider/mesh/state_test.go
+++ b/provider/mesh/state_test.go
@@ -13,7 +13,7 @@ import (
 )
 
 func TestNotificationStateGC(t *testing.T) {
-	now := time.Now()
+	now := utcNow()
 
 	initial := map[string]notificationEntry{
 		"1": {true, now},
@@ -43,7 +43,7 @@ func TestNotificationStateGC(t *testing.T) {
 
 func TestSilenceStateGC(t *testing.T) {
 	var (
-		now = time.Now()
+		now = utcNow()
 
 		id1 = uuid.NewV4()
 		id2 = uuid.NewV4()
@@ -90,7 +90,7 @@ func TestSilenceStateGC(t *testing.T) {
 
 func TestSilenceStateSet(t *testing.T) {
 	var (
-		now      = time.Now()
+		now      = utcNow()
 		id1      = uuid.NewV4()
 		matchers = types.NewMatchers(types.NewMatcher("a", "b"))
 	)
@@ -126,10 +126,11 @@ func TestSilenceStateSet(t *testing.T) {
 				},
 			},
 			input: &types.Silence{
-				ID:        id1,
-				Matchers:  matchers,
-				StartsAt:  now.Add(time.Minute),
-				EndsAt:    now.Add(time.Hour),
+				ID:       id1,
+				Matchers: matchers,
+				// Different input timezones must be normalized to UTC.
+				StartsAt:  now.Add(time.Minute).In(time.FixedZone("test", 100000)),
+				EndsAt:    now.Add(time.Hour).In(time.FixedZone("test", 10000000)),
 				CreatedBy: "x",
 				Comment:   "x",
 			},
@@ -251,7 +252,7 @@ func TestSilenceStateSet(t *testing.T) {
 
 func TestSilenceStateDel(t *testing.T) {
 	var (
-		now      = time.Now()
+		now      = utcNow()
 		id1      = uuid.NewV4()
 		matchers = types.NewMatchers(types.NewMatcher("a", "b"))
 	)
@@ -352,7 +353,7 @@ func TestSilenceStateDel(t *testing.T) {
 
 func TestSilenceModAllowed(t *testing.T) {
 	var (
-		now      = time.Now()
+		now      = utcNow()
 		id1      = uuid.NewV4()
 		matchers = types.NewMatchers(types.NewMatcher("a", "b"))
 	)