This is the 9872nd most frequent Japanese word.
計る
"To measure" or "to calculate."
計る is used here to mean 'to measure', specifically referring to assessing the temperature.
この部屋の温度を計りましょう。
Let's measure the temperature of this room.
計る is used here to mean 'to gauge or evaluate', referring to assessing subjective ability.
彼の実力を正確に計るのは難しい。
It is difficult to accurately gauge his ability.
計る in this context indicates 'to estimate or calculate', referring to determining the time for an activity.