Frequently Asked Questions

2. Is there a free demo?

Yes. We have defined a region in which you may make unlimited forecast requests. This area surrounds Central Otago on the South Island of New Zealand. The region's bounds are:

Longitude between 168 and 172
Latitude between -47 and -43

To request forecasts within this box, you don't even need to sign up for an account. This allows you to try out the service over time, to develop your application, and get a real test drive before you decide to buy.

Demo of free region, XML
Demo of free region, JSON

2. How do I get support?

Send an email to us from the Contact Us link in the top menu bar of the website.

3. What countries are covered? How good is the forecast resolution?

The GFS forecasts cover the entire world. For efficiency, we omit a few largely unpopulated area: large areas of open ocean, and anything north of 61 latitude or south of 51 latitude. If you live in an area which says that no forecast is available, let us know the latitude and longitude where you clicked, and we can see about adding coverage there.

The resolution of the GFS model is 0.5 degrees. This is approximately 20-30 miles depending on your latitude. That is, weather forecasts are spaced about 30 miles apart, and may not give different forecasts for neighboring cities or different neighborhoods within a city.

4. How often are the GFS forecasts updated?

The GFS weather prediction model runs every 6 hours, at midnight, 6am, noon, and 6pm UTC. Our system downloads these forecasts an hour or two later.

5. How accurate are the GFS weather forecasts?

This is a hard question to answer. We can highlight some trends and present an analogy.

  • First, all modern weather prediction models seem to be about the same in terms of accuracy. Some articles claim that one is better than another, but then an article is presented which contradicts this.
  • Second, accuracy diminishes as the forecast is extended. Forecast days 1 to 5 seem quite accurate but days 6 and 7 are less accurate.
  • Lastly, all the forecasts have become better over the last decade. Based on this, we expect them to become even better in the future.

To understand the forecast processes think of the following analogy. Try forecasting when a bus will arrive at each stop. The time between this stop and the next can be predicted within a minute or two, but your predictions will be further off as you try to predict the time at stops further away. This is because the bus's movement depends on many variables: traffic, traffic lights, passenger load, stops on route. Like the bus, weather depends on a great many variables which accumulate over time.

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