The PPL practice exam at the end of volume 2 has these two questions. I'm not sure the explanation for either answer; can anyone help?

121. You would expect calm conditions at an aerodrome in the morning to persist for a longer period if:
a. there was a heavy overcast of cloud
b. the sky was clear
c. the relative humidity was high
d. the atmosphere was unstable
Answer: A

126. With reference to the fig 2.13 on page 72, the conditions to be expected at YPPH (in a high region with isobar mostly parallel to equator) at the time of the chart are:
a. cold foggy
b. hot with an easterly wind
c. cool with an easterly wind
d. hot with a westerly wind
Answer: B

For the second I understand why it's an easterly wind, but how can you tell the temperature?

Question 121
a heavy overcast of cloud prevents the sun's radiation from heating the ground. Therefore the surface air remains cold for longer. That delays the onset of convection so the surface air remains almost stationery and conditions remain calm.

Question 126
The text says that the chart is valid for 0500UTC. The air is circulating anti-clockwise about the high so the wind at Perth is coming from central Australia and it's early afternoon. It would be a hot dry wind.

Thanks!