The stats on the weather page

Weather fascinates people, a fact reflected in the number of calls and e-mails that come in at a steady pace dealing with the moon and the sun and the tides and every other feature on the print edition's weather page. Since Jan. 16, changes to the page have brought a different sort of question -- "Where has Helsinki gone?" and "Where's Sault Ste. Marie?" The answer to the question of missing cities is in another posting on this page, one that explains the narrower width of pages. (The good news is, 10 of those cities are back as of Jan. 25. Reappearing are six U.S. cities -- Columbia, S.C.; Medford, Ore.; Pueblo, Colo.; San Antonio; Springfield, Mo.; and Tallahassee. Also part of the list again are four worldwide cities -- Brussels; Edinburgh; Helsinki; and Regina. As for why there's room now for those cities: In redesigning the page, editors initially miscalculated what could fit.)

But lots of other questions come in regularly, too, about the page that features more than just temperatures. Details are given for surf, sea, diving conditions and the tides; there's an ultraviolet index, air quality readings and more. (Much of the same information is at a link at latimes.com -- the online site includes the ability to search for other weather-related facts, too. Doppler radar sites, anyone?)

Mark Phillips has been involved in editing the weather page since it was a half-page in the mid-1980s, and has been editor full-time for almost 20 years. He gives some answers to most-often asked questions.

Our troops are there: Why isn't Baghdad listed in the "U.S. And Worldwide Cities" report?

The war in Iraq has been going on since March 2003, and the question continues to come in. The answer: A few days before the U.S. offensive against Iraq in 2003, the official provider of international weather data to The Times -- The National Weather Service's Internet Weather Source -- stopped listing actual temperature reports from Baghdad. We are not certain who (the U.S. military, the National Oceanic and Atmospheric Administration, or others) ended those reports or why.

However, it has been a longstanding practice of The Times to publish only temperature data that are actually from a listed location and managed by organizations recognized as legitimate providers of weather information.

The Times plans to resume publishing Baghdad reports as soon as the data again become available for publication from the National Weather Service. 

How do you choose which locations to list in the "California Cities" table?

Most of the cities that are in the daily "high/low/precipitation" listing have weather stations that are managed by the National Weather Service, or other agencies that have sophisticated equipment (such as lifeguard services, water agencies or public works departments).

But for various historical and geographical reasons, there's a smattering of places that are not NWS sites, too. For example, of the 10 that aren't affiliated with the National Weather Service, Whittier is there because it's representative of the coastal plain -- the stretch of land that  sits between the coast and the valleys of Southern California -- and it's a city with deep historical roots (it was incorporated in 1898 and is home of Pio Pico State Historic Park, named for California’s last Mexican governor). And of the NWS sites, Hesperia was among those chosen to be listed because of its elevation (3,191 feet above sea level), and because many of its residents make the daily two-hour commute to their workplace in downtown L.A.

But wait: Some of the sites listed under "California Cities" aren't even cities!

Wrightwood is an unincorporated village, and UCLA isn't a city either, readers point out on occasion.

Yes, says Phillips, "cities" is a good catchall phrase, but several sites are on the list for the geographical or other reasons explained above. They're all official in their own way, though; they are NWS "cooperative observers" that have their own automated weather stations, and the information is reported by government employees who have been trained in how to read the data.

(Readers occasionally offer to provide The Times with daily temperature readings from their areas; they should instead go to this site to find out where NWS Weather Forecast Offices could use observers.)

Who started the cooperative weather program?

Actually, no reader has asked that. But the answer: Thomas Jefferson. Here's a brief history.

Why is "xx" sometimes given instead of the temperature?

Under "weather notes," at the bottom of the page, it notes that "xx" indicates an acknowledgment that data are missing. But it doesn't say why.

It might mean that a reporting station's sensors or other equipment is malfunctioning or needs maintenance (in which case a diagnostic specialist is needed; sometimes the equipment is down for weeks). Also, for some sites, employees call The Times directly; because of city office hours, scheduling, vacation time, etc., the reports are not reported seven days a week.

I see "National Extremes" listed on the lower right of the page. But one day I saw a temperature on the "California cities" list that was higher than that day's "extreme." Why?

That's a category with an asterisk. The "National Extremes in the 48 states" entry includes some fine print that says, "National Weather Service stations only." That means those "highest" and "lowest" temperatures include only the cities that have readings done by the National Weather Service. As noted above, a few places listed on the "California Cities" list aren't associated with the National Weather Service, so sometimes the "national extremes" . . . aren't really the national extremes.