Trying to get the first Tuesday of a specific month

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Posted on by CU21081425-1

I've been trying to work a flow to send out an email for events that occur on a specific day of the month. However I cannot get the logic right, and flow keeps telling me the expression is invalid, and I cannot for the life of me see why.

Basically we have a event on the 1st tuesday of specific months, the idea is when someone submits a form, it replies with an email saying the next dates are the next 4 dates from today - I'm processing them into an array and ordering them in the email so it makes sense. I just can't seem to get the formula quite correct to calculate the date for each month.

I just get expression is invalid

addDays(
    startOfMonth(
        addToTime(
            utcNow(),
            if(greater(int(formatDateTime(utcNow(), 'MM')), 8), 12 - int(formatDateTime(utcNow(), 'MM')) + 8, 8 - int(formatDateTime(utcNow(), 'MM'))),
            'Month'
        )
    ),
    mod(9 - dayOfWeek(
        startOfMonth(
            addToTime(
                utcNow(),
                if(greater(int(formatDateTime(utcNow(), 'MM')), 8), 12 - int(formatDateTime(utcNow(), 'MM')) + 8, 8 - int(formatDateTime(utcNow(), 'MM'))),
                'Month'
            )
        )
    ), 7)
)

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Building flows

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David_MA 12,982 Super User 2025 Season 2 on at

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I am not sure I completely know how to achieve what you want, but I see where you are going with your expression. However, I might try starting it with this expression dayOfWeek(startOfMonth(utcNow())) instead. Knowing the day of the week the month started will help to determine the first Tuesday. dayOfWeek returns a number from 0 to 6 with 0 being Sunday and Saturday being 6. For August 2024, this returns 4 since it started on a Thursday. You would then know you need to add five days to this to get to the first Tuesday.

Since you need the first Tuesday, you could use a switch on the outcome of the expression to set a variable for how many days you need to add to get to the first Tuesday.

Sunday (0) add 2

Monday (1) add 1

Tuesday (2) add 0

Wednesday (3) add 6

Thursday (4) add 5

Friday (5) add 4

Saturday (6) add 3

Of course, you will want to test this in case my math is off. And maybe you can figure out how to do it all with one expression.

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takolota1 4,974 Moderator on at

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This template offers a way to get any specified date: https://community.powerplatform.com/galleries/gallery-posts/?postid=25e31954-13c5-4a1e-8c5b-8db4202970d2

Basically it generates a dates table in a JSON array & then you can filter to whatever date you want using Filter array actions.

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lbendlin 8,479 Super User 2025 Season 2 on at

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Remember that this data is immutable. You can simply prepare a list of the first tuesday of all the months in the next ten years and then check if your date is in the list. (list=array)

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