diff --git a/packages/jsapi-utils/src/DateUtils.test.ts b/packages/jsapi-utils/src/DateUtils.test.ts
index aabdaf7564..7349844bbf 100644
--- a/packages/jsapi-utils/src/DateUtils.test.ts
+++ b/packages/jsapi-utils/src/DateUtils.test.ts
@@ -109,6 +109,37 @@ describe('dateTimeString parsing tests', () => {
     );
   });
 
+  it('handles YYYY-xxx', () => {
+    testDateTimeString('2012-mar', {
+      year: '2012',
+      month: 'mar',
+    });
+
+    testDateTimeString('2012-march', {
+      year: '2012',
+      month: 'march',
+    });
+  });
+
+  it('handles YYYY-m-d', () => {
+    testDateTimeString('2012-4-6', {
+      year: '2012',
+      month: '4',
+      date: '6',
+    });
+
+    testDateTimeString(
+      '2012-04-20 overflow',
+      {
+        year: '2012',
+        month: '04',
+        date: '20',
+        overflow: ' overflow',
+      },
+      true
+    );
+  });
+
   it('handles YYYY-mm-dd', () => {
     testDateTimeString('2012-04-20', {
       year: '2012',
@@ -304,6 +335,7 @@ describe('dateTimeString parsing tests', () => {
 
   it('throws an error for invalid dates', () => {
     testDateTimeStringThrows('not a date');
+    testDateTimeStringThrows('2013-231-04');
     testDateTimeStringThrows('20133-23-04');
     testDateTimeStringThrows('2013-23-043');
     testDateTimeStringThrows('2013-23-34zzz');
@@ -449,7 +481,7 @@ describe('getJsDate', () => {
   });
 });
 
-describe('trimDateTimeStringOverflow', () => {
+describe('trimDateTimeStringTimeZone', () => {
   const dateTimeTexts = [
     '2024',
     '2012-04',
@@ -463,7 +495,7 @@ describe('trimDateTimeStringOverflow', () => {
   it.each(dateTimeTexts)(
     'should return given string if no overflow: %s',
     given => {
-      const actual = DateUtils.trimDateTimeStringOverflow(given);
+      const actual = DateUtils.trimDateTimeStringTimeZone(given);
       expect(actual).toEqual(given);
     }
   );
@@ -472,8 +504,29 @@ describe('trimDateTimeStringOverflow', () => {
     'should trim date time string overflow: %s',
     expected => {
       const given = `${expected} overflow`;
-      const actual = DateUtils.trimDateTimeStringOverflow(given);
+      const actual = DateUtils.trimDateTimeStringTimeZone(given);
       expect(actual).toEqual(expected);
     }
   );
+
+  it.each([
+    '2024overflow',
+    '2012-04overflow',
+    '2012-04-20overflow',
+    '2012-04-20T12overflow',
+    '2012-04-20T12:13overflow',
+    '2012-04-20T12:13:14overflow',
+    '2012-04-20T12:13:14.321overflow',
+    '2024overflow',
+    '2012-04  overflow',
+    '2012-04-20  overflow',
+    '2012-04-20T12  overflow',
+    '2012-04-20T12:13  overflow',
+    '2012-04-20T12:13:14  overflow',
+    '2012-04-20T12:13:14.321  overflow',
+  ])('should throw for invalid timezone overflow: %s', invalidOverflow => {
+    expect(() => DateUtils.trimDateTimeStringTimeZone(invalidOverflow)).toThrow(
+      `Unexpected timezone format in overflow: '${invalidOverflow}'`
+    );
+  });
 });
diff --git a/packages/jsapi-utils/src/DateUtils.ts b/packages/jsapi-utils/src/DateUtils.ts
index 95311ab9de..59090ba317 100644
--- a/packages/jsapi-utils/src/DateUtils.ts
+++ b/packages/jsapi-utils/src/DateUtils.ts
@@ -1,7 +1,7 @@
 import type { dh as DhType } from '@deephaven/jsapi-types';
 
 const DATE_TIME_REGEX =
-  /\s*(\d{4})([-./]([\da-z]+))?([-./](\d{1,2}))?([tT\s](\d{2})([:](\d{2}))?([:](\d{2}))?([.](\d{1,9}))?)?(.*)/;
+  /\s*(\d{4})([-./](\d{1,2}|[a-z]+))?([-./](\d{1,2}))?([tT\s](\d{2})([:](\d{2}))?([:](\d{2}))?([.](\d{1,9}))?)?(.*)/;
 
 interface DateParts<T> {
   year: T;
@@ -247,6 +247,7 @@ export class DateUtils {
       nanos,
       overflow,
     ] = result;
+
     if (!allowOverflow && overflow != null && overflow.length > 0) {
       throw new Error(
         `Unexpected characters after date string '${dateTimeString}': ${overflow}`
@@ -388,7 +389,7 @@ export class DateUtils {
    * @param dateTimeString The date time string to trim
    * @returns The date time string without overflow
    */
-  static trimDateTimeStringOverflow(dateTimeString: string): string {
+  static trimDateTimeStringTimeZone(dateTimeString: string): string {
     const { overflow = '' } = DateUtils.parseDateTimeString(
       dateTimeString,
       true
@@ -398,6 +399,14 @@ export class DateUtils {
       return dateTimeString;
     }
 
+    // Expecting timezone overflow to be a single space followed by some
+    // combination of letters
+    if (!/^\s[A-Za-z]+/.test(overflow)) {
+      throw new Error(
+        `Unexpected timezone format in overflow: '${dateTimeString}'`
+      );
+    }
+
     return dateTimeString.slice(0, -overflow.length);
   }
 }
diff --git a/packages/jsapi-utils/src/TableUtils.test.ts b/packages/jsapi-utils/src/TableUtils.test.ts
index 73f0927ff8..694ce574e9 100644
--- a/packages/jsapi-utils/src/TableUtils.test.ts
+++ b/packages/jsapi-utils/src/TableUtils.test.ts
@@ -659,7 +659,7 @@ describe('makeFilterValue', () => {
     const value = '2023-12-21';
     mockTableUtils.makeFilterValue(columnType, value);
     expect(mockDh.FilterValue.ofNumber).toHaveBeenCalledWith(
-      DateUtils.trimDateTimeStringOverflow(value)
+      DateUtils.trimDateTimeStringTimeZone(value)
     );
   });
 
@@ -773,7 +773,7 @@ describe('makeSearchTextFilter', () => {
           mockTableUtils.makeQuickDateFilterWithOperation
         ).toHaveBeenCalledWith(
           dateColumn,
-          DateUtils.trimDateTimeStringOverflow(searchText),
+          DateUtils.trimDateTimeStringTimeZone(searchText),
           'eq',
           mockTimeZone
         );
diff --git a/packages/jsapi-utils/src/TableUtils.ts b/packages/jsapi-utils/src/TableUtils.ts
index fffeb1d729..4312be8c46 100644
--- a/packages/jsapi-utils/src/TableUtils.ts
+++ b/packages/jsapi-utils/src/TableUtils.ts
@@ -1719,7 +1719,7 @@ export class TableUtils {
       if (valueType === this.dh.ValueType.DATETIME) {
         return this.makeQuickDateFilterWithOperation(
           column,
-          DateUtils.trimDateTimeStringOverflow(searchText),
+          DateUtils.trimDateTimeStringTimeZone(searchText),
           'eq',
           timeZone
         );
@@ -1889,7 +1889,7 @@ export class TableUtils {
     }
     if (TableUtils.isDateType(type)) {
       return dh.FilterValue.ofNumber(
-        DateUtils.trimDateTimeStringOverflow(value) as unknown as number
+        DateUtils.trimDateTimeStringTimeZone(value) as unknown as number
       );
     }