There's a couple things you can do.
Since we can't see the rest of your UI, here's a couple thoughts. Feel free to comment, and I'll update my answer.
1: Don't Expand, but scroll within: use a fade w/ CSS
Try setting a faded border bottom, so some of the values are obscured. You can pair this with showing a scroll bar when the users pointer enters the chart area. This also depends on how you're rendering your charts, and your UI implementation.
2: If you have room, expand
If this chart sits in a page, not constrained to smaller dashboard tile, you can have a bottom boundary, with a MORE link. This can expand the visualization, so users can scroll up and down the page itself to see more values.
Thoughts about data display:
One thing i notice in your graph is that it's showing temperature comparisons.
You have a lot of blue ink here, for data points that are individual points. One way to rework this is to use a dot plot, or a lollipop chart.
This way you could probably pack more values into the space to begin with, and wondering if there's a possibility to maybe have out of range values in a different color, as it looks like you have med, high and very high (not sure if this color change is doable, see the library you're using to test it out).
Again, just a thought, because the bars intense color don't necessarily add to the understanding here.
Using a dot plot, I can scan vertically, and count the number of points within a given range fairly quickly (you could also add summary figures at top if that was important to know).