What's the default color for placeholder text in UITextField?

The colour is #C7C7CD (r: 199 g:199 b: 205) (as what pterry26 said)

and the font-family is HelveticaNeue-Medium and size is 16

Note that this is a guess at what the color looks like on a screen. For the actual values, simply inspect the Apple code for attributedPlaceholder.

You can get this colour from inspecting the attributedPlaceholder from the UITextField.

The default seems to be: NSColor = "UIExtendedSRGBColorSpace 0 0 0.0980392 0.22";

You could add an extension (or category) on UIColor:

extension UIColor {
    static var placeholderGray: UIColor {
        return UIColor(colorLiteralRed: 0, green: 0, blue: 0.0980392, alpha: 0.22)
    }
}

2018, latest syntax is just:

extension UIColor {
    static var officialApplePlaceholderGray: UIColor {
        return UIColor(red: 0, green: 0, blue: 0.0980392, alpha: 0.22)
    }
}

#colorLiteralRed was deprecated. Be aware of this in some cases.