The darker the roof color is the more heat it attracts and hold. I don't know what climate you're in, so I don't know if this would be desirable or not. I don't think there's anything wrong with the current color. If you do go darker, don't go too much darker.

Thanks, the roof is old and leaking, which is why we have to change it. The blue siding is staying for now but we may change it in the future. Since we have to change the roof, I thought now would be the time to change the metal colour or we could just let it stay silver.

We have a mix of white and brown wood coloured window trim on the house, which we could change to either all white, all wood or even black, at lowish cost, so that might be an option in terms of other exterior updates that we can currently afford.

Here is another picture of the house -

I’d stick with the gray color. It complements the beautiful stonework.

I think a slightly deeper grey would be nice. When budget allows consider changing siding to a nice grey- green color.

I get it - can't afford to do everything at once, and that is fine, but you should have a plan in place before doing any changes.

What do you want the exterior to look like in 5 years? Do you want to replace the metal with another metal roof or something else? What is the best roofing for your climate? What is the best color for your climate?

I like @jackowskib s vision of a soft green siding with all wood-colored trim and stonework.

"Compared to dark colors, light colors such as white, light bronze, beige and peach are better at reflecting the sun’s heat rather than absorbing it into the building." https://www.abcmetalroofing.com/inspiration/roof-walls-colors/color-visualizer/#:~:text=by these authorities.-,Energy Efficiency,absorbing it into the building.

Not having a clue what your options are, I went here: https://www.roofingcalc.com/metal-roof-colors/

I imagine you would want a color that would blend in, like a stone color. Would you mind saying what brand of roofing you plan to use? I think that would help with the suggestions. Also, if you have thoughts about what siding color appeals to you, that might help. 

I had no idea that metal roofs were available in textures resembling shingles, stone tiles, or clay tiles (Tamco). This article was mind-blowing. 😁 I really appreciate your post. I look forward to seeing what ideas you like. I would think on this long and hard, because the options are much greater than before, and your chosen material will last longer than most.

Going for a medium gray will give you more color options when you’re ready to redo your house color.

Go for a light color!

Charcoal would give it a modern farmhouse look. Use the color on trim/windows too. Make sure your attic insulation is good and then the dark color will matter less.