Thanks for visiting our site! As we grow to reach a larger audience of avid photographers and sunrise/sunset lovers, we’ve prepared this how-to guide for successfully interpreting our forecasts.

First and foremost, the image that you see on our homepage is tailored to serve your specific sunset and sunrise forecast. The time next to “Valid” is out of 24-hours, and will most closely display the hour that the sun sets at your location and subsequent timezone.

For meteorologists and weather enthusiasts, we have included information about the computer models that we ingest data from to create our forecasts. The two computer models that we run or data off of are:

– The 3km NAM – This is a mesoscale numerical weather model capable of resolving features that vary from one town to another; our forecasts for the United States use the data from this weather model.
– The 13km GFS – This is a synoptic scale numerical weather model capable of resolving all of the features that make good sunsets and sunrises. If you’re outside the United States you’re viewing our forecasts using data from this model.

If you want to read more about the other information that is shown on our graphics, more information is provided below:

“Valid At” — Time that the weather conditions in the image are predicted to occur

On the homepage, this is the time when the sunset and sunrise occur for your timezone. The homepage image displays the conversion from the models time to your timezone, and serves you the correct time for sunrise and sunset.

“Forecast Hour” — Label for each recorded hour of model data

For example, if the image reads 'Forecast Hour 1', and you're viewing the forecast from the 3km NAM, the weather model has completed one hour of computing. The image is predicting the atmospheric conditions one hour from when it first started forecasting.

“Initialization Hour” — Cutoff time of our latest weather data

For example, if the Initialization Hour is '19Z' the weather model's first hour it computes is 19Z. - (This information isn't necessarily crucial, it's just a piece of information that's beneficial to note how close the model started computing relative to when sunrise and sunset occur.)