When one measurement was not enough

Text A: an original contemporary practice extract.

On a bright afternoon, the thermometer in our small greenhouse recorded 18°C. That seemed warm enough for the young plants, so I left them there overnight instead of carrying them back into the shed. By sunrise, several leaves had been damaged by the cold. The afternoon measurement had been correct, but I had treated the temperature at one moment as though it described the whole night.

Before leaving another tray in the greenhouse, I recorded the temperature at intervals from evening until morning. The later measurements revealed how quickly the warmth disappeared after sunset. I still checked the afternoon temperature, but I no longer expected it to predict conditions many hours later.

Text B: an original contemporary practice extract.

I timed the journey to the community centre during the school holidays and completed it in twenty minutes. When I began making the same journey on weekday mornings, crowded roads regularly added another fifteen minutes. My original timing was accurate for the quiet morning when I recorded it, yet I had used it as if traffic conditions never changed.

I repeated the journey on several ordinary weekdays before setting my departure time. This did not prove that the first measurement was wrong. It showed that a result gathered under one set of conditions could not represent every occasion on which I needed to travel.

Both texts describe the limitations of the measurements.

What similarities do the limitations of the measurements share in these extracts? Use evidence from both texts to support your answer.