Have a play with JS - Weather Forecast.xar.

It provides a text-based output for a City input and much more.
The "image" is about 6kB, so light enough for emails - even those that block images.

The main Blue Placeholder is an IFRAME that can be standalone.
You can change its code to anywhere you wish: <iframe id="forecast" src="https://wttr.in/London" width=100% height=100%></iframe>.

The JavaScript Placeholder will alter the Blue & Red Placeholders' location following a Form INPUT and pressing the Go button.

The smaller current detail, the Red Placeholder, is a PNG with a transparency, which you could set up as an overlay.

I have provided information on the form of inputs the forecaster accepts.

Keep warm or cool as you choose but keep safe.

Acorn

Click image for larger version. 

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