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Accuracy of (Yahoo) weather readings?

A

AgingGeek

macrumors regular
Original poster
May 21, 2007
104
0
What is the general opinion of the weather widget accuracy here?

I'm beginning to question how accurate it is. As an example, when we got back from the beach (escaping the high of 107), the iPhone widget showed a temp of 100 at 7:30 at night. But the car readout showed 91, and it was clearly not 100 degrees.

Is it a lack of accuracy, or a lack of frequent updates on the readings? Anyone know how Yahoo gets it's reading?
 
I believe the APP updates from Yahoo each time you open it. To verify, check Yahoo's page for the same city at the same time and see if it's truly updating to sync with Yahoo. If it is then Yahoo needs to update THEIR info more frequently.
 
Temperture readings are taken in specific places so it can vary depending how far away you are. Was the temperature on yahoo on the beach? Coastal and inland temps could easily vary that much.
 
Seems to work fine for me. I have a temp readout in my car that is very accurate and my iPhone has always been within 1 degree of my car when i check.
 
I guess I have to clarify the obvious assumptions:

- Yes, I realize the app updates from Yahoo everytime you open it. I was wondering how often YAHOO updates their inforation.

- No, I was not confusing the coastal temps with inland temps. This was a reading for the same location where the car was.
 
The issue with all weather reporting is knowing precisely where the weather is being reported. For example, when you see the temperature for Los Angeles, is it the downtown temperature (now collected at USC) or the airport? The difference can be huge on any given summer day. Also, temperatures are broadcasted by the NWS only once an hour, and not even reliably that often. Yahoo can only get the data as often as the NWS provides it.
 
Yahoo weather is crap!

I live in Denver, and Yahoo weather is always 3-5 degree Farenheit lower than the actual temperature. Also, it is always wrong compared to the 5 local news stations weather forecasts. I also compared it to some of the surburban communities temperatures and Yahoo is always wrong.

I wish we had the option of choosing another weather info source.

I wish the weather icon on the menu page would display the current temp like the calendar app icon shows the current date.
 
IJ Reilly said:
the temperature for Los Angeles, is it the downtown temperature (now collected at USC) or the airport? The difference can be huge on any given summer day.
Click to expand...


Same in many places. Here in San Diego the weather on all the news channels actually has three different forecast for the same area (Coastal, Inland and Desert and some do four including Mountains - all within a 45 mile radius). The temperature in the City of San Diego can vary as much as 10-15 degrees or more on any given day.
 
FreeState said:
Same in many places. Here in San Diego the weather on all the news channels actually has three different forecast for the same area (Coastal, Inland and Desert). The temperature in the City of San Diego can vary as much as 10-15 degrees or more on any given day.
Click to expand...

Exactly. Every one of these weather sites (including weather.com) is simply repackaging NWS data, and this data itself has some problems. If you're seriously interested in weather you will quickly learn about these limitations, particularly in areas where many different climate zones are packed very closely together (Southern California being a prime example). For sure, your iPhone is never going to be an accurate thermometer. ;)
 
IJ Reilly said:
The issue with all weather reporting is knowing precisely where the weather is being reported. For example, when you see the temperature for Los Angeles, is it the downtown temperature (now collected at USC) or the airport? The difference can be huge on any given summer day. Also, temperatures are broadcasted by the NWS only once an hour, and not even reliably that often. Yahoo can only get the data as often as the NWS provides it.
Click to expand...

OK, that makes more sense if it's NWS broadcasting once an hour. (My example town is only 4 miles in diameter, so it shouldn't vary that much, and in fact the car reading was taken just 2 blocks from city hall).

Agree with previous poster, would be good to see a choice, such as the weather underground, etc. And of course, they should all be brodcasting standard XML formats for the data!
 
igrover said:
I live in Denver, and Yahoo weather is always 3-5 degree Farenheit lower than the actual temperature. Also, it is always wrong compared to the 5 local news stations weather forecasts. I also compared it to some of the surburban communities temperatures and Yahoo is always wrong.
Click to expand...

Of course, Denver is a whole different ball of wax. Just spent 20 years there, and I learned to just ignore the forecasts - they were always wrong! And it changes every 5 minutes!
 
AgingGeek said:
OK, that makes more sense if it's NWS broadcasting once an hour. (My example town is only 4 miles in diameter, so it shouldn't vary that much, and in fact the car reading was taken just 2 blocks from city hall).

Agree with previous poster, would be good to see a choice, such as the weather underground, etc. And of course, they should all be brodcasting standard XML formats for the data!
Click to expand...

You don't say where you are, but no matter where, the most likely location for the current conditions reports is the airport (even though as George Carlin observed, "nobody lives at the airport.") The entire system is was created for and is still geared towards providing aviation weather.

Anyway, it doesn't matter which of the sources you use -- they all get their information from the NWS. Maybe some day the iPhone will be coordinated with the NWS's "Point Forecast" system. Better, but still far from perfect.
 
Very innacurate

Weather.com Yahoo London forecasts on iphone continue to be ramdom and unrelated to weather. There is a systematic downward bias on the London summer temperature forecast of about 4 degrees. At most times of day, the forecast high displayed on my iphone is several degrees below the actual temperature, even in the morning. Currently iphone shows london actual 25C, and a maximum of 22C shown on the same screen. The forecast highs are several degrees below those provided by reputable organisations such as the UK met office:http://www.metoffice.gov.uk/weather/uk/se/se_forecast_weather.html. They are around 5-10C below those for neighbouring Paris which has a similar climate. This consistent downward temperature forecast bias is a daily summer occurrence and has gone on for years. I have plenty of screencaps. I have tried to post on weather.com the simple suggestion that they monitor London forecasts against actuals out-turns and make the necessary bias correction. Despite taking the time, my posts have not been approved by the moderator. It's a pity yahoo weather is provided as a default. It probably explains why they have no incentive to improve the accuracy. I suggest switching to a proper weather app.
 
Wow, a thread dating back to the first days of the original iPhone it seems.
 
What I have learned is that the ability of any random person to guess the temperature outside by nothing more than feel within 5-10 degrees is pretty crap. Further, weather apps say something different than my car which is different than the temperature readings you sometimes see on digital billboards and other such devices. This is not in defense of any one device or service, but if the temps are within 5-ish degrees of one another I am generally happy with the information I am given. When it's raining I always see rain. Snowing shows me snow. Cloudy means clouds. I am pretty happy with my weather info widget, personally.
 
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