Why was 32 degrees for 3 consecutive days chosen as the threshold for a heat wave? Why not 30 degrees?

Question

Why did they choose that specific number? 30 is considered a hot day but not a heat wave?

Just wondering because Calgary is expecting 30 today.

Answer 1

The best way to answer that is looking at the Temperature through Farenheit. 32 degrees C equals about 90 degrees F. While 30 degrees C equals about 86 degrees F (notice I say about because really, 30 degrees C equals about 2 or 3 different numbers in F, I used the formula to find those answers). So 30 degrees Celcius isn't in danger territory, while 32 is (with that being said, here in America we use Farenheit, which very few countries use. So I can say I can stand 86 much more then 90). Hope that helps.

Answer 2

Like the guy above said, it's an arbitrary number chosen due to it being 90 on the F scale. 80 is too low, and 100 is too high. Although in some parts of the world, it has to be over 40 C to be considered a heatwave (104 F). It's all relative.