July 13, 2017

Will You Get Free Windows on August 6?

Nearly every day lately there is a huge color advertisement in the Seattle Times offering FREE WINDOWS for your home if the temperatures reaches 89F on Seafair Sunday (August 6th).  Here is an example:

Several people have asked my take on it...so here it is.   I emailed the advertiser to get the exact rules.   IF you have already ordered windows from them and the temperature reaches or exceeds 89F at Seattle Tacoma Airport on August 6th, the windows will be free.

So, what are the chances you can win big on those new triple-pane beauties?  Is this a good bet?  Let's check the climatology at Seattle-Tacoma Airport, where data is available from 1948 to now.   Thus, we have 69 years to look at.

It turns out that maximum temperature reached 89F or more at Sea-Tac  ONLY ONCE during that period--91F in 1972.  

So based on the climatology of Sea-Tac, there is only a 1.4% chance of securing those free windows.    The odds look awfully good for the "house."  

Some of you might argue, that global warming might be helpful in winning this bet and that climatology might be giving us an underestimate of the probability of getting to the magic 89F.  Good point.

Looking at several regional stations, the warming trend over the period was about 1F.  Not enough to make a huge difference.  Make it a 2% chance.

It appears that the odds provided by our friends in the window industry would make casino operators blush.

Typical chances of winning at blackjack is 46%.

Roulette?  Pick a single number and your chances are 1 in 37 or 2.7%.  Much better than the odds given by the window folks.  So buy the windows if you need them (I could use some myself), but don't expect to get free ones.

Now if already signed up for deal and were thinking of giving the Sea-Tac thermometers a little "help", keep in mind that the sensors are between the runways at the airport, and there is probably little chance of bribing the National Weather Service technicians who calibrate the thermometers.  Call me if you want their telephone numbers.


  1. Cliff the NWS guys don't have to do anything nefarious, they can just bring back the old equipment that they successfully used for years:


  2. Why 89 degrees. One degree to seem so much less than 90? 89 degrees in Eastern Washington would be right on the money. Now that would be risky. If they want my attention, offer exactly what the average is for that day.

    Off topic, but what's the longest dry streak in Seattle history?

  3. Your estimate is definitely a lowball. I looked at the last 50 years for dates within a week of August 6th (7/30-8/13) and found that the high temperature was at least 89 on 7.3 percent of those dates. In the last 10 years, the figure is 8.7 percent. You should have considered whether the historical scarcity of warm temperatures on August 6th was signal or noise.

  4. I think it is safe to assume that the window people have insured the risk. The actuary will use a methodology similar to yours. So let's say the insurance company charges 2 to 3% to cover the risk of this promotion. A low cost for marketing assuming that it stimulates sales by a significant amount.

  5. Too bad there isn't some sort of device creating lots of hot air near that sensor between the runways at SeaTac airport...


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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