The wxPython GUI toolkit has a number of calendar widgets, but the one that is most customizable is the wx.lib.calendar widget. Here we expanded it to colour the weekends and the holidays supplied by a dictionary of 'month: list of holiday dates in month' pairs. Since some holiday dates can change from year to year and country to country, it's up to you to update it in the code.

# experiment with wxPython's wx.lib.calendar
# show weekends and holidays in different colour
# tested with Python25 and wxPython28   vegaseat   31jul2007

import wx
import wx.lib.calendar

class Calendar_Panel(wx.Panel):
    """ create a panel with a calendar on it"""
    def __init__(self, parent, id):
        # create a panel
        wx.Panel.__init__(self, parent, id)

        # create a label on the panel
        self.label1 = wx.StaticText(self, id, "", wx.Point(25, 220))

        # create the calendar
        self.cal = wx.lib.calendar.Calendar(self, id, pos=(25, 35), size=(200, 180))

        # get the current month & year
        start_month = self.cal.GetMonth()
        start_year = self.cal.GetYear()

        # set some of the colours
        self.SetBackgroundColour("yellow")
        self.cal.SetWeekColor('white', 'blue')
        self.cal.SetColor(wx.lib.calendar.COLOR_WEEKEND_FONT, 'green')
        self.cal.SetColor(wx.lib.calendar.COLOR_WEEKEND_BACKGROUND, 'white')
        self.cal.ShowWeekEnd()

        # colour holidays of current month
        self.set_days = holidays[start_month]
        self.cal.AddSelect(self.set_days, 'red', 'white')
        self.cal.Refresh()

        # mouse click on a day
        self.Bind(wx.lib.calendar.EVT_CALENDAR, self.OnCalSelected)

        # create year spin
        self.texty = wx.TextCtrl(self, -1, str(start_year), pos=(25, 10), size=(50, -1))
        h = self.texty.GetSize().height
        self.spiny = wx.SpinButton(self, -1, pos=(70, 10), size=(h*2, h))
        self.spiny.SetRange(1980, 2010)
        self.spiny.SetValue(start_year)
        self.Bind(wx.EVT_SPIN, self.OnSpiny, self.spiny)

        # create month spin
        self.textm = wx.TextCtrl(self, -1, str(start_month), pos=(130, 10), size=(50, -1))
        h = self.textm.GetSize().height
        self.spinm = wx.SpinButton(self, -1, pos=(170, 10), size=(h*2, h))
        self.spinm.SetRange(1, 12)
        self.spinm.SetValue(start_month)
        self.Bind(wx.EVT_SPIN, self.OnSpinm, self.spinm)

    def OnCalSelected(self, evt):
        text = "Date selected = %02d/%02d/%d" % (evt.month, evt.day, evt.year)
        self.label1.SetLabel(text)

    def OnSpiny(self, event):
        year = event.GetPosition()
        self.texty.SetValue(str(year))
        self.cal.SetYear(year)
        self.ResetDisplay()

    def OnSpinm(self, event):
        month = event.GetPosition()
        self.textm.SetValue(str(month))
        self.cal.SetMonth(month)
        self.ResetDisplay()

    def ResetDisplay(self):
        # reset holiday colour
        self.cal.AddSelect(self.set_days, 'black', 'white')
        # get number of the month
        month = self.cal.GetMonth()
        set_days = holidays[month]
        # set new holiday colour
        self.cal.AddSelect(set_days, 'red', 'white')
        self.cal.Refresh()
        # keep present list to reset colour
        self.set_days = set_days


# fill these dates out for the present year
# some could change with another year
# {month: list of holiday dates in month}
holidays = {
1: [1],
2: [13],
3: [22],
4: [3],
5: [29],
6: [15],
7: [4, 11],
8: [],
9: [3],
10: [],
11: [27, 26],
12: [24, 25]
}

app = wx.PySimpleApp()
# create a window/frame, no parent, -1 is default ID
frame = wx.Frame(None, -1, "Simple calendar", size = (260, 280))
# instanciate the class
Calendar_Panel(frame, -1)
frame.Show(1)
app.MainLoop()
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