import tkinter as tk
from tkcalendar import Calendar
import datetime

root = tk.Tk()
root.title("My calendar")
root.geometry("600x400")

events = {'2022-09-28': ('Tehran', 'meeting'),
          '2022-08-15': ('Mashhad', 'meeting'),
          '2022-07-30': ('Isfahan', 'meeting')}

cal = Calendar(root, selectmode='day', year=2022, month=8)

for k in events.keys():
    date = datetime.datetime.strptime(k, '%Y-%m-%d').date()
    cal.calevent_create(date, events[k][0], events[k][1])

cal.tag_config('meeting', background='violet red', foreground='white')
cal.pack(fill='both', expand=True)

root.mainloop()