Calc - When making scale from date to date, how can I align the grid to "month", not just "31"(which is only approximate)?

Each month has different number of days. I want the X axis scale to be aligned to beginning of month, not just settling with "Ok, every month has ~31 days. Can I?

For a reasonable answer it is essential to know of what type of chart you are talking.
Please edit your question in a way making clear what you actually want to achieve. As it originally was worded, I simply don’t understand it.
You should also rework the subject to be more concise and clear?

Use a Line chart or almost any other chart type (that makes sense) than XY and the date column as category, then the first of each month is automatically chosen as major tick.

Background: for XY charts the X-axis is a numeric axis and dates are just numbers (days since null-date) formatted differently.

Been troubled by this myself. Thanks, @erAck, for the insight.