diff --git a/digitalocean/database/resource_database_cluster.go b/digitalocean/database/resource_database_cluster.go
index 8331dea22..2ef9c803b 100644
--- a/digitalocean/database/resource_database_cluster.go
+++ b/digitalocean/database/resource_database_cluster.go
@@ -96,8 +96,9 @@ func ResourceDigitalOceanDatabaseCluster() *schema.Resource {
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						"day": {
-							Type:     schema.TypeString,
-							Required: true,
+							Type:         schema.TypeString,
+							Required:     true,
+							ValidateFunc: validation.IsDayOfTheWeek(true),
 						},
 						"hour": {
 							Type:     schema.TypeString,
diff --git a/digitalocean/kubernetes/resource_kubernetes_cluster.go b/digitalocean/kubernetes/resource_kubernetes_cluster.go
index 9abb46df8..2b548b3bd 100644
--- a/digitalocean/kubernetes/resource_kubernetes_cluster.go
+++ b/digitalocean/kubernetes/resource_kubernetes_cluster.go
@@ -124,6 +124,17 @@ func ResourceDigitalOceanKubernetesCluster() *schema.Resource {
 							Type:     schema.TypeString,
 							Optional: true,
 							Computed: true,
+							ValidateFunc: validation.StringInSlice([]string{
+								"any",
+								"monday",
+								"tuesday",
+								"wednesday",
+								"thursday",
+								"friday",
+								"saturday",
+								"sunday"},
+								true,
+							),
 						},
 						"start_time": {
 							Type:     schema.TypeString,
diff --git a/docs/resources/database_cluster.md b/docs/resources/database_cluster.md
index e5b7da774..7e89253a8 100644
--- a/docs/resources/database_cluster.md
+++ b/docs/resources/database_cluster.md
@@ -133,8 +133,8 @@ The following arguments are supported:
 
 `maintenance_window` supports the following:
 
-* `day` - (Required) The day of the week on which to apply maintenance updates.
-* `hour` - (Required) The hour in UTC at which maintenance updates will be applied in 24 hour format.
+* `day` - (Required) The day of the week on which to apply maintenance updates. May be one of `monday` through `sunday`.
+* `hour` - (Required) The hour in UTC at which maintenance updates will be applied as a string in 24 hour format, e.g. `13:00`.
 
 * `backup_restore` - (Optional) Create a new database cluster based on a backup of an existing cluster.