diff --git a/web/app/components/base/date-and-time-picker/time-picker/index.spec.tsx b/web/app/components/base/date-and-time-picker/time-picker/index.spec.tsx
new file mode 100644
index 0000000000..40bc2928c8
--- /dev/null
+++ b/web/app/components/base/date-and-time-picker/time-picker/index.spec.tsx
@@ -0,0 +1,95 @@
+import React from 'react'
+import { fireEvent, render, screen } from '@testing-library/react'
+import TimePicker from './index'
+import dayjs from '../utils/dayjs'
+import { isDayjsObject } from '../utils/dayjs'
+
+jest.mock('react-i18next', () => ({
+  useTranslation: () => ({
+    t: (key: string) => {
+      if (key === 'time.defaultPlaceholder') return 'Pick a time...'
+      if (key === 'time.operation.now') return 'Now'
+      if (key === 'time.operation.ok') return 'OK'
+      if (key === 'common.operation.clear') return 'Clear'
+      return key
+    },
+  }),
+}))
+
+jest.mock('@/app/components/base/portal-to-follow-elem', () => ({
+  PortalToFollowElem: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+  PortalToFollowElemTrigger: ({ children, onClick }: { children: React.ReactNode, onClick: (e: React.MouseEvent) => void }) => (
+    <div onClick={onClick}>{children}</div>
+  ),
+  PortalToFollowElemContent: ({ children }: { children: React.ReactNode }) => (
+    <div data-testid="timepicker-content">{children}</div>
+  ),
+}))
+
+jest.mock('./options', () => () => <div data-testid="time-options" />)
+jest.mock('./header', () => () => <div data-testid="time-header" />)
+
+describe('TimePicker', () => {
+  const baseProps = {
+    onChange: jest.fn(),
+    onClear: jest.fn(),
+  }
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+  })
+
+  test('renders formatted value for string input (Issue #26692 regression)', () => {
+    render(
+      <TimePicker
+        {...baseProps}
+        value="18:45"
+        timezone="UTC"
+      />,
+    )
+
+    expect(screen.getByDisplayValue('06:45 PM')).toBeInTheDocument()
+  })
+
+  test('confirms cleared value when confirming without selection', () => {
+    render(
+      <TimePicker
+        {...baseProps}
+        value={dayjs('2024-01-01T03:30:00Z')}
+        timezone="UTC"
+      />,
+    )
+
+    const input = screen.getByRole('textbox')
+    fireEvent.click(input)
+
+    const clearButton = screen.getByRole('button', { name: /clear/i })
+    fireEvent.click(clearButton)
+
+    const confirmButton = screen.getByRole('button', { name: 'OK' })
+    fireEvent.click(confirmButton)
+
+    expect(baseProps.onChange).toHaveBeenCalledTimes(1)
+    expect(baseProps.onChange).toHaveBeenCalledWith(undefined)
+    expect(baseProps.onClear).not.toHaveBeenCalled()
+  })
+
+  test('selecting current time emits timezone-aware value', () => {
+    const onChange = jest.fn()
+    render(
+      <TimePicker
+        {...baseProps}
+        onChange={onChange}
+        timezone="America/New_York"
+      />,
+    )
+
+    const nowButton = screen.getByRole('button', { name: 'Now' })
+    fireEvent.click(nowButton)
+
+    expect(onChange).toHaveBeenCalledTimes(1)
+    const emitted = onChange.mock.calls[0][0]
+    expect(isDayjsObject(emitted)).toBe(true)
+    expect(emitted?.utcOffset()).toBe(dayjs().tz('America/New_York').utcOffset())
+  })
+})
diff --git a/web/app/components/base/date-and-time-picker/time-picker/index.tsx b/web/app/components/base/date-and-time-picker/time-picker/index.tsx
index 1fb2cfed11..f23fcf8f4e 100644
--- a/web/app/components/base/date-and-time-picker/time-picker/index.tsx
+++ b/web/app/components/base/date-and-time-picker/time-picker/index.tsx
@@ -1,6 +1,13 @@
 import React, { useCallback, useEffect, useRef, useState } from 'react'
-import type { Period, TimePickerProps } from '../types'
-import dayjs, { cloneTime, getDateWithTimezone, getHourIn12Hour } from '../utils/dayjs'
+import type { Dayjs } from 'dayjs'
+import { Period } from '../types'
+import type { TimePickerProps } from '../types'
+import dayjs, {
+  getDateWithTimezone,
+  getHourIn12Hour,
+  isDayjsObject,
+  toDayjs,
+} from '../utils/dayjs'
 import {
   PortalToFollowElem,
   PortalToFollowElemContent,
@@ -13,6 +20,11 @@ import { useTranslation } from 'react-i18next'
 import { RiCloseCircleFill, RiTimeLine } from '@remixicon/react'
 import cn from '@/utils/classnames'
 
+const to24Hour = (hour12: string, period: Period) => {
+  const normalized = Number.parseInt(hour12, 10) % 12
+  return period === Period.PM ? normalized + 12 : normalized
+}
+
 const TimePicker = ({
   value,
   timezone,
@@ -28,7 +40,11 @@ const TimePicker = ({
   const [isOpen, setIsOpen] = useState(false)
   const containerRef = useRef<HTMLDivElement>(null)
   const isInitial = useRef(true)
-  const [selectedTime, setSelectedTime] = useState(() => value ? getDateWithTimezone({ timezone, date: value }) : undefined)
+
+  // Initialize selectedTime
+  const [selectedTime, setSelectedTime] = useState(() => {
+    return toDayjs(value, { timezone })
+  })
 
   useEffect(() => {
     const handleClickOutside = (event: MouseEvent) => {
@@ -39,20 +55,47 @@ const TimePicker = ({
     return () => document.removeEventListener('mousedown', handleClickOutside)
   }, [])
 
+  // Track previous values to avoid unnecessary updates
+  const prevValueRef = useRef(value)
+  const prevTimezoneRef = useRef(timezone)
+
   useEffect(() => {
     if (isInitial.current) {
       isInitial.current = false
+      // Save initial values on first render
+      prevValueRef.current = value
+      prevTimezoneRef.current = timezone
       return
     }
-    if (value) {
-      const newValue = getDateWithTimezone({ date: value, timezone })
-      setSelectedTime(newValue)
-      onChange(newValue)
+
+    // Only update when timezone changes but value doesn't
+    const valueChanged = prevValueRef.current !== value
+    const timezoneChanged = prevTimezoneRef.current !== timezone
+
+    // Update reference values
+    prevValueRef.current = value
+    prevTimezoneRef.current = timezone
+
+    // Skip if neither timezone changed nor value changed
+    if (!timezoneChanged && !valueChanged) return
+
+    if (value !== undefined && value !== null) {
+      const dayjsValue = toDayjs(value, { timezone })
+      if (!dayjsValue) return
+
+      setSelectedTime(dayjsValue)
+
+      if (timezoneChanged && !valueChanged)
+        onChange(dayjsValue)
+      return
     }
-    else {
-      setSelectedTime(prev => prev ? getDateWithTimezone({ date: prev, timezone }) : undefined)
-    }
-  }, [timezone])
+
+    setSelectedTime((prev) => {
+      if (!isDayjsObject(prev))
+        return undefined
+      return timezone ? getDateWithTimezone({ date: prev, timezone }) : prev
+    })
+  }, [timezone, value, onChange])
 
   const handleClickTrigger = (e: React.MouseEvent) => {
     e.stopPropagation()
@@ -61,8 +104,16 @@ const TimePicker = ({
       return
     }
     setIsOpen(true)
-    if (value)
-      setSelectedTime(value)
+
+    if (value) {
+      const dayjsValue = toDayjs(value, { timezone })
+      const needsUpdate = dayjsValue && (
+        !selectedTime
+        || !isDayjsObject(selectedTime)
+        || !dayjsValue.isSame(selectedTime, 'minute')
+      )
+      if (needsUpdate) setSelectedTime(dayjsValue)
+    }
   }
 
   const handleClear = (e: React.MouseEvent) => {
@@ -73,42 +124,68 @@ const TimePicker = ({
   }
 
   const handleTimeSelect = (hour: string, minute: string, period: Period) => {
-    const newTime = cloneTime(dayjs(), dayjs(`1/1/2000 ${hour}:${minute} ${period}`))
+    const periodAdjustedHour = to24Hour(hour, period)
+    const nextMinute = Number.parseInt(minute, 10)
     setSelectedTime((prev) => {
-      return prev ? cloneTime(prev, newTime) : newTime
+      const reference = isDayjsObject(prev)
+        ? prev
+        : (timezone ? getDateWithTimezone({ timezone }) : dayjs()).startOf('minute')
+      return reference
+        .set('hour', periodAdjustedHour)
+        .set('minute', nextMinute)
+        .set('second', 0)
+        .set('millisecond', 0)
     })
   }
 
+  const getSafeTimeObject = useCallback(() => {
+    if (isDayjsObject(selectedTime))
+      return selectedTime
+    return (timezone ? getDateWithTimezone({ timezone }) : dayjs()).startOf('day')
+  }, [selectedTime, timezone])
+
   const handleSelectHour = useCallback((hour: string) => {
-    const time = selectedTime || dayjs().startOf('day')
+    const time = getSafeTimeObject()
     handleTimeSelect(hour, time.minute().toString().padStart(2, '0'), time.format('A') as Period)
-  }, [selectedTime])
+  }, [getSafeTimeObject])
 
   const handleSelectMinute = useCallback((minute: string) => {
-    const time = selectedTime || dayjs().startOf('day')
+    const time = getSafeTimeObject()
     handleTimeSelect(getHourIn12Hour(time).toString().padStart(2, '0'), minute, time.format('A') as Period)
-  }, [selectedTime])
+  }, [getSafeTimeObject])
 
   const handleSelectPeriod = useCallback((period: Period) => {
-    const time = selectedTime || dayjs().startOf('day')
+    const time = getSafeTimeObject()
     handleTimeSelect(getHourIn12Hour(time).toString().padStart(2, '0'), time.minute().toString().padStart(2, '0'), period)
-  }, [selectedTime])
+  }, [getSafeTimeObject])
 
   const handleSelectCurrentTime = useCallback(() => {
     const newDate = getDateWithTimezone({ timezone })
     setSelectedTime(newDate)
     onChange(newDate)
     setIsOpen(false)
-  }, [onChange, timezone])
+  }, [timezone, onChange])
 
   const handleConfirm = useCallback(() => {
-    onChange(selectedTime)
+    const valueToEmit = isDayjsObject(selectedTime) ? selectedTime : undefined
+    onChange(valueToEmit)
     setIsOpen(false)
-  }, [onChange, selectedTime])
+  }, [selectedTime, onChange])
 
   const timeFormat = 'hh:mm A'
-  const displayValue = value?.format(timeFormat) || ''
-  const placeholderDate = isOpen && selectedTime ? selectedTime.format(timeFormat) : (placeholder || t('time.defaultPlaceholder'))
+
+  const formatTimeValue = useCallback((timeValue: string | Dayjs | undefined): string => {
+    if (!timeValue) return ''
+
+    const dayjsValue = toDayjs(timeValue, { timezone })
+    return dayjsValue?.format(timeFormat) || ''
+  }, [timezone])
+
+  const displayValue = formatTimeValue(value)
+
+  const placeholderDate = isOpen && isDayjsObject(selectedTime)
+    ? selectedTime.format(timeFormat)
+    : (placeholder || t('time.defaultPlaceholder'))
 
   const inputElem = (
     <input
@@ -146,6 +223,8 @@ const TimePicker = ({
                 'hidden h-4 w-4 shrink-0 text-text-quaternary',
                 (displayValue || (isOpen && selectedTime)) && 'hover:text-text-secondary group-hover:inline-block',
               )}
+              role='button'
+              aria-label={t('common.operation.clear')}
               onClick={handleClear}
             />
           </div>
diff --git a/web/app/components/base/date-and-time-picker/types.ts b/web/app/components/base/date-and-time-picker/types.ts
index 4ac01c142a..b51c2ebb01 100644
--- a/web/app/components/base/date-and-time-picker/types.ts
+++ b/web/app/components/base/date-and-time-picker/types.ts
@@ -54,7 +54,7 @@ export type TriggerParams = {
   onClick: (e: React.MouseEvent) => void
 }
 export type TimePickerProps = {
-  value: Dayjs | undefined
+  value: Dayjs | string | undefined
   timezone?: string
   placeholder?: string
   onChange: (date: Dayjs | undefined) => void
diff --git a/web/app/components/base/date-and-time-picker/utils/dayjs.spec.ts b/web/app/components/base/date-and-time-picker/utils/dayjs.spec.ts
new file mode 100644
index 0000000000..549ab01029
--- /dev/null
+++ b/web/app/components/base/date-and-time-picker/utils/dayjs.spec.ts
@@ -0,0 +1,67 @@
+import dayjs from './dayjs'
+import {
+  getDateWithTimezone,
+  isDayjsObject,
+  toDayjs,
+} from './dayjs'
+
+describe('dayjs utilities', () => {
+  const timezone = 'UTC'
+
+  test('toDayjs parses time-only strings with timezone support', () => {
+    const result = toDayjs('18:45', { timezone })
+    expect(result).toBeDefined()
+    expect(result?.format('HH:mm')).toBe('18:45')
+    expect(result?.utcOffset()).toBe(getDateWithTimezone({ timezone }).utcOffset())
+  })
+
+  test('toDayjs parses 12-hour time strings', () => {
+    const tz = 'America/New_York'
+    const result = toDayjs('07:15 PM', { timezone: tz })
+    expect(result).toBeDefined()
+    expect(result?.format('HH:mm')).toBe('19:15')
+    expect(result?.utcOffset()).toBe(getDateWithTimezone({ timezone: tz }).utcOffset())
+  })
+
+  test('isDayjsObject detects dayjs instances', () => {
+    const date = dayjs()
+    expect(isDayjsObject(date)).toBe(true)
+    expect(isDayjsObject(getDateWithTimezone({ timezone }))).toBe(true)
+    expect(isDayjsObject('2024-01-01')).toBe(false)
+    expect(isDayjsObject({})).toBe(false)
+  })
+
+  test('toDayjs parses datetime strings in target timezone', () => {
+    const value = '2024-05-01 12:00:00'
+    const tz = 'America/New_York'
+
+    const result = toDayjs(value, { timezone: tz })
+
+    expect(result).toBeDefined()
+    expect(result?.hour()).toBe(12)
+    expect(result?.format('YYYY-MM-DD HH:mm')).toBe('2024-05-01 12:00')
+  })
+
+  test('toDayjs parses ISO datetime strings in target timezone', () => {
+    const value = '2024-05-01T14:30:00'
+    const tz = 'Europe/London'
+
+    const result = toDayjs(value, { timezone: tz })
+
+    expect(result).toBeDefined()
+    expect(result?.hour()).toBe(14)
+    expect(result?.minute()).toBe(30)
+  })
+
+  test('toDayjs handles dates without time component', () => {
+    const value = '2024-05-01'
+    const tz = 'America/Los_Angeles'
+
+    const result = toDayjs(value, { timezone: tz })
+
+    expect(result).toBeDefined()
+    expect(result?.format('YYYY-MM-DD')).toBe('2024-05-01')
+    expect(result?.hour()).toBe(0)
+    expect(result?.minute()).toBe(0)
+  })
+})
diff --git a/web/app/components/base/date-and-time-picker/utils/dayjs.ts b/web/app/components/base/date-and-time-picker/utils/dayjs.ts
index fef35bf6ca..808b50247a 100644
--- a/web/app/components/base/date-and-time-picker/utils/dayjs.ts
+++ b/web/app/components/base/date-and-time-picker/utils/dayjs.ts
@@ -10,6 +10,25 @@ dayjs.extend(timezone)
 export default dayjs
 
 const monthMaps: Record<string, Day[]> = {}
+const DEFAULT_OFFSET_STR = 'UTC+0'
+const TIME_ONLY_REGEX = /^(\d{1,2}):(\d{2})(?::(\d{2})(?:\.(\d{1,3}))?)?$/
+const TIME_ONLY_12H_REGEX = /^(\d{1,2}):(\d{2})(?::(\d{2}))?\s?(AM|PM)$/i
+
+const COMMON_PARSE_FORMATS = [
+  'YYYY-MM-DD',
+  'YYYY/MM/DD',
+  'DD-MM-YYYY',
+  'DD/MM/YYYY',
+  'MM-DD-YYYY',
+  'MM/DD/YYYY',
+  'YYYY-MM-DDTHH:mm:ss.SSSZ',
+  'YYYY-MM-DDTHH:mm:ssZ',
+  'YYYY-MM-DD HH:mm:ss',
+  'YYYY-MM-DDTHH:mm',
+  'YYYY-MM-DDTHH:mmZ',
+  'YYYY-MM-DDTHH:mm:ss',
+  'YYYY-MM-DDTHH:mm:ss.SSS',
+]
 
 export const cloneTime = (targetDate: Dayjs, sourceDate: Dayjs) => {
   return targetDate.clone()
@@ -76,21 +95,116 @@ export const getHourIn12Hour = (date: Dayjs) => {
   return hour === 0 ? 12 : hour >= 12 ? hour - 12 : hour
 }
 
-export const getDateWithTimezone = (props: { date?: Dayjs, timezone?: string }) => {
-  return props.date ? dayjs.tz(props.date, props.timezone) : dayjs().tz(props.timezone)
+export const getDateWithTimezone = ({ date, timezone }: { date?: Dayjs, timezone?: string }) => {
+  if (!timezone)
+    return (date ?? dayjs()).clone()
+  return date ? dayjs.tz(date, timezone) : dayjs().tz(timezone)
 }
 
-// Asia/Shanghai -> UTC+8
-const DEFAULT_OFFSET_STR = 'UTC+0'
 export const convertTimezoneToOffsetStr = (timezone?: string) => {
   if (!timezone)
     return DEFAULT_OFFSET_STR
   const tzItem = tz.find(item => item.value === timezone)
-  if(!tzItem)
+  if (!tzItem)
     return DEFAULT_OFFSET_STR
   return `UTC${tzItem.name.charAt(0)}${tzItem.name.charAt(2)}`
 }
 
+export const isDayjsObject = (value: unknown): value is Dayjs => dayjs.isDayjs(value)
+
+export type ToDayjsOptions = {
+  timezone?: string
+  format?: string
+  formats?: string[]
+}
+
+const warnParseFailure = (value: string) => {
+  if (process.env.NODE_ENV !== 'production')
+    console.warn('[TimePicker] Failed to parse time value', value)
+}
+
+const normalizeMillisecond = (value: string | undefined) => {
+  if (!value) return 0
+  if (value.length === 3) return Number(value)
+  if (value.length > 3) return Number(value.slice(0, 3))
+  return Number(value.padEnd(3, '0'))
+}
+
+const applyTimezone = (date: Dayjs, timezone?: string) => {
+  return timezone ? getDateWithTimezone({ date, timezone }) : date
+}
+
+export const toDayjs = (value: string | Dayjs | undefined, options: ToDayjsOptions = {}): Dayjs | undefined => {
+  if (!value)
+    return undefined
+
+  const { timezone: tzName, format, formats } = options
+
+  if (isDayjsObject(value))
+    return applyTimezone(value, tzName)
+
+  if (typeof value !== 'string')
+    return undefined
+
+  const trimmed = value.trim()
+
+  if (format) {
+    const parsedWithFormat = tzName
+      ? dayjs.tz(trimmed, format, tzName, true)
+      : dayjs(trimmed, format, true)
+    if (parsedWithFormat.isValid())
+      return parsedWithFormat
+  }
+
+  const timeMatch = TIME_ONLY_REGEX.exec(trimmed)
+  if (timeMatch) {
+    const base = applyTimezone(dayjs(), tzName).startOf('day')
+    const rawHour = Number(timeMatch[1])
+    const minute = Number(timeMatch[2])
+    const second = timeMatch[3] ? Number(timeMatch[3]) : 0
+    const millisecond = normalizeMillisecond(timeMatch[4])
+
+    return base
+      .set('hour', rawHour)
+      .set('minute', minute)
+      .set('second', second)
+      .set('millisecond', millisecond)
+  }
+
+  const timeMatch12h = TIME_ONLY_12H_REGEX.exec(trimmed)
+  if (timeMatch12h) {
+    const base = applyTimezone(dayjs(), tzName).startOf('day')
+    let hour = Number(timeMatch12h[1]) % 12
+    const isPM = timeMatch12h[4]?.toUpperCase() === 'PM'
+    if (isPM)
+      hour += 12
+    const minute = Number(timeMatch12h[2])
+    const second = timeMatch12h[3] ? Number(timeMatch12h[3]) : 0
+
+    return base
+      .set('hour', hour)
+      .set('minute', minute)
+      .set('second', second)
+      .set('millisecond', 0)
+  }
+
+  const candidateFormats = formats ?? COMMON_PARSE_FORMATS
+  for (const fmt of candidateFormats) {
+    const parsed = tzName
+      ? dayjs.tz(trimmed, fmt, tzName, true)
+      : dayjs(trimmed, fmt, true)
+    if (parsed.isValid())
+      return parsed
+  }
+
+  const fallbackParsed = tzName ? dayjs.tz(trimmed, tzName) : dayjs(trimmed)
+  if (fallbackParsed.isValid())
+    return fallbackParsed
+
+  warnParseFailure(value)
+  return undefined
+}
+
 // Parse date with multiple format support
 export const parseDateWithFormat = (dateString: string, format?: string): Dayjs | null => {
   if (!dateString) return null
@@ -103,15 +217,7 @@ export const parseDateWithFormat = (dateString: string, format?: string): Dayjs
 
   // Try common date formats
   const formats = [
-    'YYYY-MM-DD', // Standard format
-    'YYYY/MM/DD', // Slash format
-    'DD-MM-YYYY', // European format
-    'DD/MM/YYYY', // European slash format
-    'MM-DD-YYYY', // US format
-    'MM/DD/YYYY', // US slash format
-    'YYYY-MM-DDTHH:mm:ss.SSSZ', // ISO format
-    'YYYY-MM-DDTHH:mm:ssZ', // ISO format (no milliseconds)
-    'YYYY-MM-DD HH:mm:ss', // Standard datetime format
+    ...COMMON_PARSE_FORMATS,
   ]
 
   for (const fmt of formats) {