Wednesday, June 27, 2012

Wedding day temperature

I wanted to see which weather site was better at forecasting the temperature on our wedding day (6/16/12) in Arlington, VA.  The two sites I monitored were: and

Below is a graph of each day's high/low temperature predictions for 6/16/12.
The green line is the actual recorded high (82) and low (63) temperatures for 6/16/12. only started updating their predictions on 6/7/12.

The average root mean square of the errors for and are 2.458 and 4.172 respectively. was better at predicting the high and low temperatures for our wedding day.


  1. But this is for two weeks of prediction, with the huge errors being in the first week. Just eyeballing it, it looks like accuweather's RMS error might be lower for the last 5 days. Does the best provider switch depending on the length of the prediction?

  2. I didn't do the RMS error for just the last week, but yeah, the length of the prediction will most likely effect the RMS error... However, I'm not sure if Accuweather will be much better because I averaged the RMS error for both the high and low predictions.