How to set the height of table header in UITableView?

I found a nice hack. Add the below line after modifying the frame propery

self.tableView.tableHeaderView = self.tableView.tableHeaderView;

The trick is (I think) that the UITableView is caching the height (the frame actually) when you assign the view to the tableHeaderView property. The above line just assigns the height again.

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    sizeHeaderToFit()
}

private func sizeHeaderToFit() {
    let headerView = tableView.tableHeaderView!

    headerView.setNeedsLayout()
    headerView.layoutIfNeeded()

    let height = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height
    var frame = headerView.frame
    frame.size.height = height
    headerView.frame = frame

    tableView.tableHeaderView = headerView
}

More details can be found here

Just set the frame property of the tableHeaderView.

In case you still need it, have you tried to set the property

self.tableView.tableHeaderView 

If you calculate the heigh you need, and set a new view for tableHeaderView:

CGRect frame = self.tableView.tableHeaderView.frame;
frame.size.height = newHeight;

self.tableView.tableHeaderView = [[UIView alloc] initWithFrame:frame];

It should work.