News - Blogs - Why your thermometer is wrong

Why your thermometer is wrong!
Published: 6/30/2011 7:00 AM
Last Modified: 6/29/2011 4:40 PM

A garden thermometer displays the Aug. 4, 2010 temperature... more than 130 degrees? Switch a few of the numbers and you'll have the weather service's recorded high for that day, 103 degrees. ZACH GRAY/Tulsa World File

When no thermometer is available to remind you how hot it is (it hit 106 that day), run through a fountain! Sinai Gomez, 2, gets splashed by her aunt, Lorena Lara at 41st and Riverside in Tulsa. MICHAEL WYKE/Tulsa World

There is apparently a town in Michigan called "Hell," the perfect place for a thermometer and the KFC Colonel to announce a temperature-related promotion back in 2008. PRNewsFoto/Kentucky Fried Chicken

When Monday was declared as the first day in the 100s for Tulsa, did it surprise you?

After all, on your commute, didn't those business signs already declare the temperature to be in the 100s? Hasn't that heat index been declaring 100s for at least a week now?

First of all, heat indexes are like wind chills, so those aren't actual temperatures (read more in Jerry's blog entry on apparent temperature here). Second, your thermometer is probably wrong for a wide variety of reasons provided by Tulsa National Weather Service Data Acquisition Program Manager, Mike Teague.

1- Heat sources
Sure, your thermometer's in the shade, but what about that air conditioning unit blowing out all of that hot air? Roads, houses, buildings and parking lots can cause inaccuracies, even if the most common culprit is the sun, Teague said.

"It needs to be in the shade, or even housed in something ventilated," Teague said.

2- Ground factor
You mean my thermometer half-buried in snow or wet with morning dew is a little bit off? Teague said the coldest air is usually near the ground, so consider raising the thermometer.

"We use a standard of 2 meters, about 6 feet, above the ground," Teague said.

3- Obstructions
Ideally, Teague said thermometers should be at least 100 feet away from buildings for the most accurate readings. Realistically, Teague said the further away from buildings, trees, mountains, anything that obstructs air flow, the more accurate the thermometer.

Most of these same principles apply to rain gauges, Teague said.

So, what does the Tulsa National Weather Service use? An Automated Surface Observing System (ASOS) at the Tulsa International Airport, which monitors much more than just temperature. Built by a government contractor, ASOS (Teague pronounced it like "A-sauce") serves the dual purpose of providing aviation weather information, as well as weather information for the public.

Here is more background on why ASOS is at the airport. And if you're a bit more mistrusting of your thermometer now, you can get all of your local forecasting information from the weather service here.

--Althea Peterson

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Almanac

Jan	Feb	Mar	Apr	May	Jun
Jul	Aug	Sep	Oct	Nov	Dec

	Temperature		Precipitation
Date	High Temp	Low Temp	Total	Month to date	Historical average
1	44°	16°	0	0.00	0.05
2	59°	24°	0	0.00	0.11
3	57°	33°	0	0.00	0.16
4	68°	37°	Trace	0.00	0.21
5	69°	29°	0	0.00	0.26
6	66°	33°	0	0.00	0.32
7	59°	38°	0.05	0.05	0.38
8	51°	34°	0	0.05	0.44
9	44°	36°	0.01	0.06	0.51
10	62°	37°	0.07	0.13	0.57
11	54°	28°	0	0.13	0.64
12	44°	30°	0.25	0.38	0.70
13	55°	40°	0.01	0.39	0.76
14	°	°			0.83
15	°	°			0.89
16	°	°			0.95
17	°	°			1.02
18	°	°			1.09
19	°	°			1.16
20	°	°			1.23
21	°	°			1.31
22	°	°			1.38
23	°	°			1.46
24	°	°			1.53
25	°	°			1.61
26	°	°			1.69
27	°	°			1.77
28	°	°			1.85

TEMPERATURE

RAINFALL

SNOWFALL

Weather World

Follow Jerry Wofford on Twitter for updates during severe weather conditions.

Tulsa weather milestones of 2013 (as of Feb. 12)

Highest temperature: 70 on Jan. 11 (Record: 115 on Aug. 15, 1936)
Lowest temperature: 15 on Jan. 16 (Record: Minus-16 on Jan. 22, 1930)
Hottest month (average): 40.5 degrees in January (Record: 91.7 degrees on July 1980)
Coldest month (average): 40. 5 degrees in January (Record: 21.7 in January 1918)
Most snowfall (day): 0.1 of an inch on Feb. 12(Record: 13.2 inches on Feb. 1, 2011)
Most snowfall (month): 0.1 of an inch in February(Record: 22.5 inches in February 2011)
Most rainfall (day): 0.91 of an inch on Jan. 29 (Record: 9.27 inches on May 26-27, 1984)
Most rainfall (month): 1.54 of an inch in January (Record: 18.18 inches on September 1971)
Highest wind speed: 30 mph on Jan. 30
Previous day with any rain: Feb. 12
Previous day with 1 inch or more of rain: Oct. 17, 2012
Previous day with any snow: Feb. 12
Previous day with freezing temperatures: Feb. 12
Read regular updates on Oklahoma's unpredictable weather and learn more about meteorology from the Tulsa office of the National Weather Service.

>> Visit the main weather page
>> Send us your weather photos
>> Meet the forecasters

Contributors
Staff Writer Althea Peterson started writing for the Tulsa World in March 2007 after previous stops at the Norman Transcript in 2006 and the Oklahoma Gazette in 2005. She followed her older brother from rural Wisconsin (with a public school that never seemed to call snow days) to the University of Oklahoma, but did not follow his pursuit to study meteorology. However, she tries to find as many opportunities to report on the weather as possible.

Staff Writer Jerry Wofford came to the Tulsa World in 2010 from The Manhattan Mercury in Manhattan, Kan. Originally from western Arkansas and a graduate of the University of Oklahoma, Jerry has lived in Tornado Alley his entire life and is one of those people who goes outside when the sirens go off.

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