diff --git a/src/mito2/src/memtable.rs b/src/mito2/src/memtable.rs
index 6adc6eb96aec..942d77a209d2 100644
--- a/src/mito2/src/memtable.rs
+++ b/src/mito2/src/memtable.rs
@@ -70,7 +70,7 @@ impl Default for MemtableConfig {
 pub struct MemtableStats {
     /// The estimated bytes allocated by this memtable from heap.
     estimated_bytes: usize,
-    /// The time range that this memtable contains. It is None if
+    /// The inclusive time range that this memtable contains. It is None if
     /// and only if the memtable is empty.
     time_range: Option<(Timestamp, Timestamp)>,
     /// Total rows in memtable
diff --git a/src/mito2/src/memtable/time_partition.rs b/src/mito2/src/memtable/time_partition.rs
index 7fa03ae1bed4..21f0dd645977 100644
--- a/src/mito2/src/memtable/time_partition.rs
+++ b/src/mito2/src/memtable/time_partition.rs
@@ -168,8 +168,8 @@ impl TimePartitions {
         Ok(())
     }
 
-    /// Forks latest partition.
-    pub fn fork(&self, metadata: &RegionMetadataRef) -> Self {
+    /// Forks latest partition and updates the partition duration.
+    pub fn fork(&self, metadata: &RegionMetadataRef, part_duration: Option<Duration>) -> Self {
         let mut inner = self.inner.lock().unwrap();
         let latest_part = inner
             .parts
@@ -178,17 +178,31 @@ impl TimePartitions {
             .cloned();
 
         let Some(old_part) = latest_part else {
+            // If there is no partition, then we create a new partition with the new duration.
             return Self::new(
                 metadata.clone(),
                 self.builder.clone(),
                 inner.next_memtable_id,
-                self.part_duration,
+                part_duration,
             );
         };
+
+        let old_stats = old_part.memtable.stats();
+        // Use the max timestamp to compute the new time range for the memtable.
+        // If `part_duration` is None, the new range will be None.
+        let new_time_range =
+            old_stats
+                .time_range()
+                .zip(part_duration)
+                .and_then(|(range, bucket)| {
+                    partition_start_timestamp(range.1, bucket)
+                        .and_then(|start| PartTimeRange::from_start_duration(start, bucket))
+                });
+        // Forks the latest partition, but compute the time range based on the new duration.
         let memtable = old_part.memtable.fork(inner.alloc_memtable_id(), metadata);
         let new_part = TimePartition {
             memtable,
-            time_range: old_part.time_range,
+            time_range: new_time_range,
         };
         Self {
             inner: Mutex::new(PartitionsInner::with_partition(
@@ -238,6 +252,16 @@ impl TimePartitions {
         inner.next_memtable_id
     }
 
+    /// Creates a new empty partition list from this list and a part_duration.
+    pub(crate) fn new_with_part_duration(&self, part_duration: Option<Duration>) -> Self {
+        Self::new(
+            self.metadata.clone(),
+            self.builder.clone(),
+            self.next_memtable_id(),
+            part_duration,
+        )
+    }
+
     /// Returns all partitions.
     fn list_partitions(&self) -> PartitionVec {
         let inner = self.inner.lock().unwrap();
diff --git a/src/mito2/src/memtable/version.rs b/src/mito2/src/memtable/version.rs
index 1c7f2b7d4a25..78f8d1347522 100644
--- a/src/mito2/src/memtable/version.rs
+++ b/src/mito2/src/memtable/version.rs
@@ -15,6 +15,7 @@
 //! Memtable version.
 
 use std::sync::Arc;
+use std::time::Duration;
 
 use smallvec::SmallVec;
 use store_api::metadata::RegionMetadataRef;
@@ -65,27 +66,41 @@ impl MemtableVersion {
     /// Returns a new [MemtableVersion] which switches the old mutable memtable to immutable
     /// memtable.
     ///
+    /// It will switch to use the `time_window` provided.
+    ///
     /// Returns `None` if the mutable memtable is empty.
     pub(crate) fn freeze_mutable(
         &self,
         metadata: &RegionMetadataRef,
+        time_window: Option<Duration>,
     ) -> Result<Option<MemtableVersion>> {
         if self.mutable.is_empty() {
-            // No need to freeze the mutable memtable.
-            return Ok(None);
+            // No need to freeze the mutable memtable, but we need to check the time window.
+            if self.mutable.part_duration() == time_window {
+                // If the time window is the same, we don't need to update it.
+                return Ok(None);
+            }
+
+            // Update the time window.
+            let mutable = self.mutable.new_with_part_duration(time_window);
+            return Ok(Some(MemtableVersion {
+                mutable: Arc::new(mutable),
+                immutables: self.immutables.clone(),
+            }));
         }
 
         // Marks the mutable memtable as immutable so it can free the memory usage from our
         // soft limit.
         self.mutable.freeze()?;
         // Fork the memtable.
-        let mutable = Arc::new(self.mutable.fork(metadata));
+        let mutable = Arc::new(self.mutable.fork(metadata, time_window));
 
-        // Pushes the mutable memtable to immutable list.
         let mut immutables =
             SmallVec::with_capacity(self.immutables.len() + self.mutable.num_partitions());
-        self.mutable.list_memtables_to_small_vec(&mut immutables);
         immutables.extend(self.immutables.iter().cloned());
+        // Pushes the mutable memtable to immutable list.
+        self.mutable.list_memtables_to_small_vec(&mut immutables);
+
         Ok(Some(MemtableVersion {
             mutable,
             immutables,
diff --git a/src/mito2/src/region/version.rs b/src/mito2/src/region/version.rs
index 8e78fa4ab351..188c314837c0 100644
--- a/src/mito2/src/region/version.rs
+++ b/src/mito2/src/region/version.rs
@@ -80,8 +80,12 @@ impl VersionControl {
     /// Freezes the mutable memtable if it is not empty.
     pub(crate) fn freeze_mutable(&self) -> Result<()> {
         let version = self.current().version;
+        let time_window = version.compaction_time_window;
 
-        let Some(new_memtables) = version.memtables.freeze_mutable(&version.metadata)? else {
+        let Some(new_memtables) = version
+            .memtables
+            .freeze_mutable(&version.metadata, time_window)?
+        else {
             return Ok(());
         };