Calculator for specific weekdays

With this calculator you can determine on what date a specific day of the week occurs, for instance the third Sunday of April on or after the 15th.
The calculator doesn't check the sanity of the input, so entering data should be done carefully. Current years are 4-digit numbers, not 2 digit numbers. The calculator only works for the Gregorian calendar, which is used in most parts of the Western world.

The second Monday of August on/after the 15th, etc.
Calculate the 1st, 2nd, 3rd, 4th, if existing the 5th, or the last weekday (like Monday, Saturday, etc.) of a certain month in a certain year.
If needed, enter an offset day after or before which the counting should start. The offset day is included in the counting if it is the selected weekday.
An offset day has no effect if the last weekday (of a month) is selected. If e.g. the last Sunday on/before day n is needed, select the first Sunday on/before day n. It is also possible to select before or after instead of on/before, on/after.

Select the Nth: day: of month: year:
day no. (of this month):

requested date: (format: full year-month-day)

One of the applications of the calculator presented above, is figuring out on which date a daylight saving transition (winter time <-> summer time) occurs. Worldwide there are many different DST (daylight saving time) rules in effect. Below an example of two DST rules, calculated with the same functions that form the basis of the calculator above.

Date and time of daylight saving time


Regiondate (y-m-d) local time
Europe (zone CET)start: 02:00
end: 03:00
United States
<=2006 rules
start: 02:00
end: 02:00
United States
>=2007 rules
start: 02:00
end: 02:00

This was just an example!
See the commented JavaScript source in this file. The information in the table above is computed with the functions dstEUstart, dstEUend, dstUSstart, dstUSend, dstUS07start, dstUS07end.


Small print
You receive this application as is. No guarantees are given for the correct functioning, the usability or the correctness of the produced data. Should you plan important meetings or rituals, based on the data produced with this application, chances are that you will get into some serious problems. You as user will have to take the full risk of using this application.
Naturally, we have done our best to construct an application with a minimal amount of errors. Please report errors to the address you can build from:
ovv (at)

This page is an addition to our page:
A list with all current time zone information: time zones and dates/times of daylight saving time of all countries.
Go to/Back to the timezone index.

© Oscar van Vlijmen, March 2005
Last modified: 2006-06-19