The KPIs displayed on the Home Dashboard are showing data for the current month as standard. This means that if e.g., it's the 10th, the figures displayed are compiled over the previous 10 days. In the upper right corner you can switch to another month as well as see which month's data is displayed.
The graph shown below each KPI shows historical data. That's why the current month is not displayed on the graph. As the monthly data is not yet complete it's not included in the graph. In the example below the MTD amount of orders is 787, the graph below is displaying historical data on total orders/month in the previous 6 months.