Priceline is offering a new “sunshine guarantee” over the summer that refunds 100% of airfare, hotel and car rental charges booked through them if your vacation gets rained on. It only applies to certain destinations, and it has to rain .5 inches per day for at least half the trip, but there is no additional fee for the insurance.

My guess is a few people may actually try to book a trip hoping it rains so that they’ll get the refund. It’ll be hard to guess, though, since tickets have to be purchased at least twelve days in advance. If anyone manages to do it, let us know and we’ll send you a TechCrunch tshirt (pictures of you standing in the rain are required, preferably with you holding open a laptop or phone with the TechCrunch site displayed and some sort of thumbs up signal ).

The insurance is being provided through Weatherbill, a weather-related insurance startup founded by ex-Googler David Friedberg in early 2007.

San Francisco-based weather insurance site WeatherBill has taken $12.5 million in a round led by New Enterprise Associates and Index Ventures. Original investors Allen & Company, Atomico Investments (Skype founder Niklas Zennstrom), del.icio.us founder Joshua Schachter and Howard Morgan also participated.

Barney Schauble, a partner at Nephila Capital and WeatherBill’s risk capacity partner, will join WeatherBill’s Board of Directors. Total funding for Weatherbill to date is now $16.5 million.

WeatherBill was founded by former Googler David Friedberg. The company offers weather insurance policies to businesses – such as ski resorts, farms, airlines, construction companies, and amusement parks – with more than $1 million in net worth that have suffered losses due to unfavorable weather in the past.

Users choose a weather station via a Google Maps mashup and choose whether you want it to pay out for each hot, cold, rainy or dry day. Temperatures are set by the user by degrees and precipitation by inches.

WeatherBill hedges their own risk via their weather algorithm and also sells their risk on the back end to a number of hedge funds, in theory delivering a guaranteed profit regardless of the weather.

CEO David Friedberg says that Weatherbill has hundreds of customers and faces such high demand that it needs to bring more people aboard to increase capacity. The site has launched not only in the US but Canada, the UK, the Netherlands, Spain, Germany, and Norway as well.

See our previous WeatherBill coverage here and here.

San Francisco based WeatherBill, the service which lets you bet on the weather (it can also be used for insurance), took down their landing page and launched today.

We wrote about the company two weeks ago while it was in private beta. WeatherBill is combining an ecommerce site with a complicated weather forecasting algorithm to sell weather insurance policies to individuals and businesses.

The company is not disclosing the size of their round of funding. However, it includes venture firms NEA and Index Ventures, as well as a number of well known individuals: del.icio.us founder Joshua Schachter, Skype founder Niklas Zennstrom (through his Atomico fund) and Howard Morgan (idealab and First Round Capital), as well as others who declined to be named.

WeatherBill is perfect for small and medium sized businesses who’s businesses are affected by the weather. If a golf course wants to be paid $1,000 per rainy day, WeatherBill will create a policy on the fly for them.

The company was founded by former Googler David Friedberg.

On a side note, WeatherBill is doing some really nice things with Flash (see the tools section). Even if weather and insurance isn’t your cup of tea, you should check it out. Particularly if you are creating Flash applications yourself (I said the same thing about Jobby with their use of Ajax back in March).

David Friedberg, a former Googler, is set to launch an ambitious new site called WeatherBill, headquartered in San Francisco, in the next few weeks. WeatherBill won’t be a consumer site; rather, they are combining an ecommerce site with a complicated weather forecasting algorithm to sell weather insurance policies to individuals and businesses. And having a business isn’t a requirement to purchase a contract on WeatherBill – users can also use it to simply make a cash bet on the weather swings in a given geographic area.

Weather insurance is difficult to get and even harder to customize. Enron began to dabble in weather-related securities, who’s value would fluctuate based on actual weather down the road, but that all ended in 2001 when the company went bankrupt. Today, large energy companies trade weather policies back and forth to hedge against high or low temperatures, but everyone else is left out.

That’s where WeatherBill will come in. Anyone can buy an insurance policy for weather in a given area. Choose a weather station via a Google Maps mashup (see screenshot to right) and choose whether you want it to pay out for each hot, cold, rainy or dry day. Temperatures are set by the user by degrees, precipitation by inches. As an example, if I want to be paid $100 for every very rainy day (1/4 of an inch or more) in San Diego in March 2007, that policy will cost $370.64 and will pay up to a maximum of $3,000. Every option is variable, and so the user can decrease the amount of rain required, increase the maximum payout, etc., via an Ajax interface. A contract for a payout of as little as $1 can be created.

WeatherBill hedges their own risk via their weather algorithm, which Friedberg tells me they use to simulate 20,000 years of weather daily for each weather station. They also sell their risk on the back end to a number of hedge funds. The result is guaranteed profit for them, regardless of the weathler. All they have to do is sell policies.

WeatherBill may be useful for golf course owners, movie theaters, amusement parks and other businesses whose business varies significantly based on that day’s weather. I would imagine that having this built into things like Quickbooks and other online accounting software would be a great feature for many small businesses. The only requirement to purchase a policy is that the individual or business is an “accredited investor,” meaning they have a net worth of at least $1 million. The user has to certify this when creating an account, but no follow up is done.

WeatherBill is has raised a Series A round of financing from NEA, Index Ventures and a number of angel investors. Look for a launch in the near future. Additional screenshots below (note: these are from an early demo, and will probably change somewhat by launch).