As anyone who owns one will tell you, there's nothing quite like driving with the top down on a sunny day.

It may be clichéd, but having the wind in your hair, sun on your face and experiencing just a little more of the world around you, really does make every journey a little more fun.

While we're waiting for an affordable successor to the Tesla Roadster to enjoy some zero-emissions top-down driving, our next best option is to scan the price lists for the five convertibles offering the highest gas mileage.

Want some summer fun without using too much gas? These could be the cars for you.

2012 smart fortwo cabriolet
From $17,690

Sure, the smart fortwo isn't to everyone's taste--in fact, we're pretty sure only a small minority are genuinely fans of the two-seat city car--but it's still the most efficient convertible currently on sale.

Although you'll need to fill it with premium gas, you should see 36 mpg combined, with 34 in the city and 38 on the highway. Its tiny engine doesn't pollute much either, and you can drop the small canvas roof at any speed. It's not a great handler, but for a trip to the beach and back it'll use the least fuel here.

2012 MINI Cooper Convertible/Roadster
From $24,350

Since both the Convertible and Roadster get the same gas mileage, we're including both here. The Roadster's recent introduction now gives you a two-seat option to the Convertible's four, but both are a blast to drive and the cheeky retro styling still turns heads after several years on the market.

It doesn't sip gas like the smart, but still offers 30 mpg combined. Mileage is the same whether you go manual or automatic, and you'll also get 27 mpg city and 35 mpg highway from the 1.6-liter engine. In fact, even if you choose the turbocharged Cooper S, gas mileage doesn't suffer.

2012 Fiat 500 Cabrio
From $19,500

With only a 1.4-liter engine to the MINI Cooper's 1.6, you might expect better than 29 mpg combined from Fiat's cute cabrio, but it's still one of the more gas-sipping soft-tops out there.

The retro styling won't be to all tastes, though it does do a good job of capturing the original 1950s styling. The sliding canvas roof is also easy to use and the interior has some neat touches, even if it's a bit short on space. Still, it's a pity we don't get the twin-cylinder TwinAir engine offered in Europe.

2012 BMW Z4 sDrive28i
From $48,650

The fourth most efficient convertible on sale is a BMW sports car? We were surprised too, but with 27 mpg combined from the Z4's 2.0-liter turbocharged four-cylinder, that's where it ends up.

Naturally, the BMW performs--with an 8-speed automatic transmission, the 245-horsepower engine takes you to 60mph in 5.7 seconds and on to 155mph. And yet, it's only a few mpg off the Fiat 500 Cabrio...

2012 Mercedes-Benz SLK250
From $42,500

First a BMW, and now a Mercedes-Benz? It's true, although the Mercedes loses another 1 mpg from the BMW, for a 26 mpg combined EPA figure. It also loses a gear, with a 7-speed automatic transmission--but who's counting?

Importantly, it's also a fair bit cheaper to buy, though still out of the reach of many. Like the BMW, it gets a metal folding roof, so it's as cosy in the winter as it is breezy in the summer.

So there you go--five cars for the summer, which shouldn't break the bank at each gas station. However, we can't help wishing for an electric sports car for truly green summer thrills...


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