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The fact that points set multiple daily records per year has no bearing whatsoever on the significance, or lack thereof, of a monthly, global record. Exactly t

The fact that points set multiple daily records per year has no bearing whatsoever on the significance, or lack thereof, of a monthly, global record. Exactly the same principle applies. Look at the title of this submission. Stop and before you knee-jerk a response, contemplate that this isn't "it's hot, yo, and getting hotter". It is specifically that July was the hottest month "ever recorded", which someone quite rightfully noted was since 1880.

dang 11y ago
> before you knee-jerk a response > zealots such as yourself Stuff like this breaks the HN guidelines, and there is much of it in your comments. Please post civilly and substantively, or not at all, even when others are wrong. In fact, especially when others are wrong.
mikeash 11y ago
The exact same principle applies, yes. But the quantities are way different. Variation at a point is high. Variation for a period of a single day is high. Samples are taken frequently. Thus new records will be set regularly. Variation for the entire globe is low. Variation for a period of an entire month is low. There are twelve samples per year. Thus new records would not be expected to be set frequently. Again, what exactly is your point?
- mikeash 11y ago
  Thinking about this more, samples are actually taken at the same rate: yearly. The difference is how many different things you're tracking in each year. For regional records, you're tracking 365 events per year. Each one is compared with that day on prior years. For global records, you're tracking one event per year (since July will always be the warmest month). Thus, if you'd expect to set a new record every 50 years, then you'd see on average one global record every 50 years, but you'd see about seven daily regional records every year. Also consider that you should be seeing both record highs and record lows. Record lows continue at a good pace for regional daily records, but there hasn't been a global record low for well over a century.
  - fluidcruft 11y ago
    Records don't occur linearly for a stationary variable. That is you don't expect "an average record every 50 years". The longer you observe the signal the more more extreme the expected outlier.
    - mikeash 11y ago
      Sure, that's just a simplification to illustrate the principle. Whatever the expected recurrance for records is, you'll get a lot more of them when you're testing 365 (really 730, since you have both highs and lows) separate values each year than when you're just testing one (realy two).

dang 11y ago

> before you knee-jerk a response > zealots such as yourself Stuff like this breaks the HN guidelines, and there is much of it in your comments. Please post civilly and substantively, or not at all, even when others are wrong. In fact, especially when others are wrong.

mikeash 11y ago

The exact same principle applies, yes. But the quantities are way different. Variation at a point is high. Variation for a period of a single day is high. Samples are taken frequently. Thus new records will be set regularly. Variation for the entire globe is low. Variation for a period of an entire month is low. There are twelve samples per year. Thus new records would not be expected to be set frequently. Again, what exactly is your point?

mikeash 11y ago
Thinking about this more, samples are actually taken at the same rate: yearly. The difference is how many different things you're tracking in each year. For regional records, you're tracking 365 events per year. Each one is compared with that day on prior years. For global records, you're tracking one event per year (since July will always be the warmest month). Thus, if you'd expect to set a new record every 50 years, then you'd see on average one global record every 50 years, but you'd see about seven daily regional records every year. Also consider that you should be seeing both record highs and record lows. Record lows continue at a good pace for regional daily records, but there hasn't been a global record low for well over a century.
- fluidcruft 11y ago
  Records don't occur linearly for a stationary variable. That is you don't expect "an average record every 50 years". The longer you observe the signal the more more extreme the expected outlier.
  - mikeash 11y ago
    Sure, that's just a simplification to illustrate the principle. Whatever the expected recurrance for records is, you'll get a lot more of them when you're testing 365 (really 730, since you have both highs and lows) separate values each year than when you're just testing one (realy two).