You did not mention which temperature, but assuming you mean the processor temperature of one of its cores or the package:
Yes, absolutely the temperature can rise and fall that fast. Rate is a function of cooling method and how good a thermal bond you have between your processor and that cooling method.
Passive cooling methods require some temperature differential for heat to flow from hot to cold. The higher the differential the faster the heat flow.
Liquid cooling methods bring the cold to very close proximity to the processor itself, requiring very little temperature differential for good heat flow.
As far as I know sensors
does not guess.
Here is an example using an air cooled Intel i7-2600K processor, with known good thermal bond between the processor and the heat sink and known fast fan response time. Using turbostat instead of lm-sensors, and prime95 torture test to create high heat load:
$ sudo turbostat --Summary --quiet --show Busy%,Bzy_MHz,PkgTmp,PkgWatt,GFXWatt,IRQ --interval 0.25
Busy% Bzy_MHz IRQ PkgTmp PkgWatt GFXWatt
0.16 2029 61 37 4.16 0.12
0.14 1872 57 37 4.10 0.12
0.13 1932 60 39 4.11 0.12
52.09 3498 1251 54 47.29 0.12 <<< load applied, already 15 degress
100.00 3500 2063 58 87.15 0.12
100.00 3500 2058 60 87.55 0.12
100.00 3500 2054 62 88.07 0.12
100.00 3500 2064 63 87.96 0.12
100.00 3500 2052 64 88.29 0.12
100.00 3500 2067 64 88.12 0.12
100.00 3500 2053 64 88.13 0.12
100.00 3500 2063 65 88.30 0.12
100.00 3500 2060 66 88.56 0.12
100.00 3500 2058 65 88.35 0.12
100.00 3500 2057 65 88.30 0.12
100.00 3500 2058 66 88.78 0.12
100.00 3500 2055 66 88.40 0.12
100.00 3500 2060 67 88.56 0.12
100.00 3500 2053 67 88.84 0.12
100.00 3500 2062 67 88.57 0.12
100.00 3500 2056 67 88.56 0.12
99.99 3164 2074 62 76.39 0.12 <<< Throttling
100.00 2700 2052 61 58.25 0.12
100.00 2700 2063 60 58.34 0.12
100.00 2700 2063 60 58.14 0.12
So, sampling at 4 hertz (0.25 seconds period) we saw 52% after the load was applied, therefore we know it was roughly 1/2 way between samples. So the processor temperature went up 15 degrees in approximately 0.125 seconds.
To protect my processor for this experiment, I also ran thermald with a low trip point, and you can observe it throttling the CPU frequency after awhile.
grep "model name" /proc/cpuinfo
. If I were to guess, I would say that you have a poor thermal bond between your processor and its heat sink.