Codecanyon – Simple Weather WordPress Shortcode & Widget v.4.4.4 Free Download
If you need a simple weather display, with just the temperature and location for today, a very simple shortcode does the trick. Any other option you want, like night temperature or number of days to forecast, you can just add it to the shortcode.
If a widget works better for you, the Simple Weather plugin comes also with an easy to set-up widget, packing all the options you need.