Is your dash display of outdoor temperature accurate?

[Hacksaw]

I live in the desert SW and daily highs have been well over 100 but I've never seen the dash display read higher than 98 (and that was on a day when my home thermometer (in the shade) was showing 117*.

It's been 105 or higher every time I've driven it in the past 10 days or so, but the dash temperature only gets to the low or mid 90's.

It's not something I'd take it in to the dealer for; just wondering if there is a known issue with displaying 100+ outdoor temperatures (and if so, maybe they should just display a "flaming shit" icon to indicate it's hotter than shit, instead of a number for anything over 95 degrees ;o)).

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[Nodak]

it depends on how you look at it.

official temp measurements at taken via an infared sensor pointed at the ground and measures ground temp

the sensor in the vehicle takes ambient temp which can be lower than official temps

 

[Nodak]

Each USCRN station measures surface temperature in degrees Celsius using an infrared sensor pointed at the ground. Every five minutes, the datalogger averages two-second thermocouple-measured temperature readings to obtain 5-minute values.

Surface Air Temperature
Each USCRN station has three thermometers which report independent temperature measurements each hour. These three observed temperature value are used to derive a single official USCRN temperature value for the hour. This single value is sometimes a median and sometimes an average of various combinations of the three observed values, depending on information about which instruments agree in a pairwise comparison within 0.3°C. Each station transmits the three independent observed values; the computation of the official USCRN temperature value is done after these values arrive at NCEI. The discussion below describes the details of the three observed values.

Each station has three Thermometrics platinum resistance thermometers, each of which is housed in its own Met One 076B 7308 aspirated solar shield. Each thermometer measures the temperature (in degrees Celsius) every 2 seconds. Every 5 minutes the station datalogger computes the average of these 2-second values, giving 12 5-minute averages for each thermometer. Standard deviations are also calculated for each thermometer. Finally, a moving 5-minute average displaced 10-seconds at a time is used to determine the maximum and minimum 5-minute periods ending within the hour in question.

In addition to the thermometer values, the station also measures the speed of the fan in each aspirated shield. As the shield's fan rotates, a contact closes and generates a pulse twice per rotation. The datalogger counts these pulses every two seconds. Every hour these 2-second values are averaged to obtain an average number of pulses per second for the hour. The hourly data stream from the station thus include the average pulse rate per second for each of the three sensors. The actual speed of the fan in revolutions per second is half the pulse rate.

 

[MikeD]

Hacksaw: Thought your question was interesting and its been over 100 here but I did not get the chance to check when it was. However, I can say that dash thermometer was spot on at
84

 

[Nodak]

but then again you are comparing an ambient temp to an ambient temp. the OP is trying to compare an official temp vs an ambient temp (which i am guessing)

 

[Hacksaw]

Hacksaw: Thought your question was interesting and its been over 100 here but I did not get the chance to check when it was. However, I can say that dash thermometer was spot on at
84

Yes, I've found the dash temperature display to match pretty closely to my various outdoor thermometers when the temperature is below say 90*F. Somewhere from the low 90's and higher, the 4runner's displayed outdoor temperature (or more specifically, the thermistor or the thermocouple that is inside the engine compartment's temperature sensor) becomes non-linear, or compressed, or however you'd like to look at it. Its accuracy goes to crap above about 90*F, and is even farther off when above 100. It always reads low (by as much as 10-20 degrees).

Nodak: sorry, I'm not clear on the point you're making. Maybe the additional info above will help clarify. The difference I'm seeing is not a fixed amount, it's only different for hot temperatures, and the difference increases the hotter it is. Pretty much every day from this month through September will be well over 100 here (sometimes even longer, into October), so it's reconfirmed every day. Also, I have a thermometer that comes with a NIST calibration certificate and +/-0.5*F accuracy, so I can verify that all my other outdoor thermometers are accurate within a couple degrees.

 

[Mad Ghost]

few weeks back my weather app said Death Valley was going to be 114 and that's what the gauge said in the 4Runner as well.

 

[Nodak]

Yes, I've found the dash temperature display to match pretty closely to my various outdoor thermometers when the temperature is below say 90*F. Somewhere from the low 90's and higher, the 4runner's displayed outdoor temperature (or more specifically, the thermistor or the thermocouple that is inside the engine compartment's temperature sensor) becomes non-linear, or compressed, or however you'd like to look at it. Its accuracy goes to crap above about 90*F, and is even farther off when above 100. It always reads low (by as much as 10-20 degrees).

Nodak: sorry, I'm not clear on the point you're making. Maybe the additional info above will help clarify. The difference I'm seeing is not a fixed amount, it's only different for hot temperatures, and the difference increases the hotter it is. Pretty much every day from this month through September will be well over 100 here (sometimes even longer, into October), so it's reconfirmed every day. Also, I have a thermometer that comes with a NIST calibration certificate and +/-0.5*F accuracy, so I can verify that all my other outdoor thermometers are accurate within a couple degrees.

nope you are good.

i have to agree the temp scaling gets wonky at the extreme's.

i notice when it gets 0F to -30F cold, the temp gauge is off by 4F (i havent seen it colder than -32F here in ND ambient, not including wind chill)

i know the 4R temp sensor only goes to -40F (C)

btw -40F is the same as -40C


here is the stats for this past feb using my atlas weather station on the back deck of the house

the 17 and 18 feb were brutal temp wise



�

	High	Low	Average
Temperature	50.8 °F	-35.1 °F	6.7 °F
Dew Point	37.0 °F	-40.0 °F	-0.3 °F
Humidity	96 %	36 %	73 %
Precipitation	0.04 in	--	--

	High	Low	Average
Wind Speed	21.0 mph	0.0 mph	2.6 mph
Wind Gust	21.0 mph	--	4.1 mph
Wind Direction	--	--	WSW
Pressure	30.43 in	29.78 in	--

Temperature

Dew Point

Humidity

Speed

Pressure

Precip. Accum.

Date

High

Avg

Low

High

Avg

Low

High

Avg

Low

High

Avg

Low

High

Low

Sum

2/1/2025

30.1 °F

20.1 °F

9.1 °F

26.0 °F

15.3 °F

2.0 °F

92 %

81 %

72 %

13.0 mph

1.4 mph

0.0 mph

30.06 in

29.90 in

0.02 in

2/2/2025

19.1 °F

4.0 °F

-3.5 °F

15.0 °F

-3.2 °F

-9.0 °F

84 %

72 %

62 %

16.0 mph

3.9 mph

0.0 mph

30.09 in

29.78 in

0.00 in

2/3/2025

-3.0 °F

-6.9 °F

-13.5 °F

-8.0 °F

-13.4 °F

-19.0 °F

83 %

73 %

61 %

16.0 mph

3.8 mph

0.0 mph

29.99 in

29.89 in

0.00 in

2/4/2025

4.0 °F

-4.8 °F

-15.3 °F

-1.0 °F

-11.0 °F

-20.0 °F

81 %

74 %

60 %

8.0 mph

0.7 mph

0.0 mph

30.07 in

29.87 in

0.00 in

2/5/2025

11.2 °F

6.4 °F

0.7 °F

5.0 °F

0.2 °F

-7.0 °F

86 %

75 %

67 %

17.0 mph

2.7 mph

0.0 mph

30.11 in

29.95 in

0.00 in

2/6/2025

11.0 °F

0.8 °F

-6.9 °F

1.0 °F

-6.7 °F

-14.0 °F

76 %

71 %

61 %

18.0 mph

6.8 mph

0.0 mph

30.05 in

29.92 in

0.00 in

2/7/2025

14.5 °F

5.8 °F

-2.3 °F

6.0 °F

-0.8 °F

-9.0 °F

82 %

74 %

65 %

10.0 mph

1.8 mph

0.0 mph

30.08 in

29.90 in

0.00 in

2/8/2025

15.6 °F

3.8 °F

-6.4 °F

3.0 °F

-2.9 °F

-10.0 °F

84 %

74 %

56 %

9.0 mph

1.6 mph

0.0 mph

30.10 in

29.95 in

0.00 in

2/9/2025

13.7 °F

2.0 °F

-5.4 °F

4.0 °F

-3.8 °F

-10.0 °F

86 %

77 %

64 %

13.0 mph

3.5 mph

0.0 mph

30.12 in

29.95 in

0.00 in

2/10/2025

1.5 °F

-9.1 °F

-15.4 °F

-9.0 °F

-16.7 °F

-22.0 °F

79 %

69 %

53 %

13.0 mph

3.7 mph

0.0 mph

30.08 in

29.93 in

0.00 in

2/11/2025

7.0 °F

-7.8 °F

-17.1 °F

-8.0 °F

-17.5 °F

-25.0 °F

76 %

62 %

46 %

10.0 mph

2.4 mph

0.0 mph

30.11 in

29.96 in

0.00 in

2/12/2025

6.3 °F

-8.9 °F

-18.3 °F

-8.0 °F

-16.0 °F

-23.0 °F

82 %

71 %

47 %

6.0 mph

1.2 mph

0.0 mph

30.11 in

29.98 in

0.00 in

2/13/2025

12.0 °F

-3.3 °F

-16.7 °F

0.0 °F

-10.4 °F

-21.0 °F

83 %

72 %

55 %

11.0 mph

2.3 mph

0.0 mph

30.14 in

29.98 in

0.00 in

2/14/2025

3.9 °F

-4.1 °F

-11.2 °F

-2.0 °F

-10.0 °F

-16.0 °F

82 %

76 %

67 %

14.0 mph

2.8 mph

0.0 mph

30.19 in

30.00 in

0.00 in

2/15/2025

5.7 °F

-2.8 °F

-7.0 °F

-5.0 °F

-9.5 °F

-13.0 °F

82 %

73 %

59 %

4.0 mph

0.8 mph

0.0 mph

30.20 in

30.00 in

0.00 in

2/16/2025

-2.8 °F

-10.4 °F

-22.9 °F

-10.0 °F

-17.4 °F

-29.0 °F

81 %

72 %

55 %

12.0 mph

2.6 mph

0.0 mph

30.17 in

29.96 in

0.00 in

2/17/2025

-3.7 °F

-20.6 °F

-30.1 °F

-18.0 °F

-27.9 °F

-34.0 °F

79 %

69 %

47 %

4.0 mph

0.6 mph

0.0 mph

30.28 in

29.99 in

0.00 in

2/18/2025

2.6 °F

-19.4 °F

-35.1 °F

-13.0 °F

-27.2 °F

-40.0 °F

81 %

68 %

42 %

4.0 mph

0.3 mph

0.0 mph

30.24 in

30.02 in

0.00 in

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