How many K is 15 °C?
15 °C = 288.15 K
It is 288.15 K, so saying 288 K is fine — rounding is within 0.5%.
And how many °C is 15 K?
15 K = -258.15 °C
Formula: K = °C × 1 + 273.15
°C to K around this value
6 °C279.15K
7 °C280.15K
8 °C281.15K
9 °C282.15K
10 °C283.15K
11 °C284.15K
12 °C285.15K
13 °C286.15K
14 °C287.15K
15 °C288.15K
16 °C289.15K
17 °C290.15K
18 °C291.15K
19 °C292.15K
20 °C293.15K
21 °C294.15K
22 °C295.15K
23 °C296.15K
24 °C297.15K
25 °C298.15K