That's an excellent and very practical question. You're right to wonder about this, as it touches on urban design, material science, and environmental comfort. The short answer is: yes, a black or dark-colored trash bin will absorb more solar radiation and get hotter than a light-colored one placed in the same sunny spot. This is a basic principle of physics—darker surfaces have a lower albedo, meaning they reflect less sunlight and absorb more of its energy as heat.
On a hot summer day, the surface temperature of a dark bin can become significantly warmer to the touch than the surrounding air. This can have a couple of minor consequences. The heat might accelerate the breakdown of certain types of waste slightly and could potentially intensify odors. For the waste management worker emptying the bin, a scorching-hot surface is also an unpleasant occupational hazard.
However, is this a *bad idea* that cities should avoid? The reality is more nuanced. For the overall "urban heat island" effect—where cities are warmer than surrounding rural areas—the contribution from thousands of trash bins is minuscule compared to vast expanses of dark asphalt roads, rooftops, and concrete structures. The primary function of a public trash bin is durability, cost-effectiveness, and ease of maintenance. Dark colors, especially black or dark green, are often chosen because they are better at hiding scuffs, stains, and general wear, making them look cleaner for longer between services.
So, while the heat absorption is a real physical phenomenon, it's rarely a primary design driver. A more impactful approach for mitigating urban heat involves large-scale interventions like planting trees (which can also shade bins!), installing cool roofs, and using permeable, lighter-colored pavements. Some innovative cities are experimenting with solar-compacting bins, where the absorbed heat might even be a tangential benefit for powering the mechanism. Ultimately, the choice of bin color is a balance of practical maintenance concerns against a relatively small thermal downside.