Degree Days.net API for Automated Access to HDD and CDD

Popular, and widely used... Degree Days.net is trusted by thousands of energy professionals, academics, and energy management systems worldwide for the reasons explained here. Numerous energy software companies depend on our API, as do many larger organizations such as multinational corporations, universities, and government bodies. We are referenced in hundreds of academic publications. You need high-quality data that you and your users can trust. Our API is the source to supply it.

All the data-generation options available through our website, and more: thousands of weather stations; daily, weekly, monthly, yearly, custom, and average data breakdowns; extended historical data (no 36-month limit); even more base temperatures to choose from; hourly temperature data and advanced regression too. The API also uses the same accurate calculation processes as the website, but with intensive concurrent processing to generate the data faster.

Our API can choose the weather stations for you... You can specify the geographic locations you want data for (as postal/zip codes or longitude/latitude positions), and the API will select the best weather stations for you automatically. It chooses intelligently, considering data quality and history as well as proximity to your target locations. You can also fetch data by weather station ID or use a hybrid approach called two-stage data fetching to efficiently keep track of degree days for many thousands of building locations.

A simple, clearly-defined interface to a robust, sophisticated system... Raw temperature data is messy. Even high-quality weather stations managed by official sources like the NOAA and the UK Met Office can have irregular, missing, and erroneous readings. Our internal system for turning raw temperature data into accurate degree days (and regular hourly temperatures) is complicated. But we've carefully designed our API to shield you from this complexity and provide you with usable continuous data only (with none of the gaps or cryptic special values you'll see in data from other systems). Our system is robust, well-tested, and well-documented. We've made it as straightforward as possible for your system to take full advantage of all the work we've put into ours.

Built by specialists, for specialist applications... We specialize in degree days and energy data analysis. This is reflected in everything from the sophisticated data-calculation processes we use to the wide range of data-generation options offered by our system. Degree days are far too specialist a market for generalist weather-data providers to pay them the level of attention that we do. Whilst most weather APIs require you to fetch data one day at a time (meaning thousands of requests to assemble a full history for a location), just one call to our API will let you fetch HDD and CDD covering 10+ years, in lots of base temperatures, and broken down however you like (e.g. daily, weekly, monthly). We even offer advanced regression to help your system analyze its energy data accurately. Our API is built the way it is because we understand the sorts of specialist applications you want to use it for. We don't think you'll find that elsewhere.

Running reliably without breaking changes since launch in 2011... Over the many years since launch we've added powerful new API features and made numerous upgrades to our infrastructure, but none of these enhancements have broken any customer system or forced any customer to update their code. Long-term compatibility is a huge priority for us.

Clear pricing, affordable to businesses both large and small... We feel it's our duty to encourage worldwide energy saving by making our API accessible to smaller players as well as the enterprise market. Our prices are based on the costs of the intensive number crunching that our API does – costs that increase with each new customer we take on. To keep prices down we don't have the overhead of a sales team... Instead, signing up is a simple, automated process, with clearly-published prices that depend on the level of usage you want to reserve capacity for.