The current heatwave has broken a few local records in terms of record daily high temps. That got me to thinking about records. The expression goes "records are made to be broken". Same goes for weather records, especially in this day and age of Global Warming where natural variability bounces around a slow and steady incline of warming or so the theory goes. In such a scenario, one would assume that high temperature records would be more from recent times than from decades past. We hear tell of how the weather is becoming more and more extreme. But unfortunately for Global Warming alarmists, that isn't the case.
Let's take Ottawa. The current Environment Canada Archive has daily records for Ottawa from 1938 to 2011. I have compiled the year in which each day's record high comes from and then grouped by decades. Here is the result with one caveat and that is with tying years, I only noted the earliest year. This result is similar, not the same, but similar to US state records, shown at bottom.
As you can see, more than 1/2 of the daily record high temperatures for Ottawa are pre-1980. It is unfortunate that the rest of the 30's are not included as I am sure that there are many daily records that would still be valid today (think 30's drought/dustbowl, see chart below). The flip side of this is that 2012 is not included. This has been an anomalous year, especially March, which as I have explained previously, and corroborated by more official entities, it a result of weather pattern globally over the winter months. There will be a fair amount of 2012 daily record highs.