Why You See Your
Breath on a Cold Winter Night
Condensation can occur if moist, warm air mixes
with cold, dry air.
Temp RH SVP VP
(clear)
(clear)
(clear)
The 50-50 mix condenses into a cloud that
quickly evaporates as your exhalation
is diluted further
Temp RH SVP VPAir0oC20%6
mb 1 mb
0oC20%6
mb 1 mb(clear)Breath36oC80%63
mb55 mb
36oC80%63
mb55 mb(clear)50-5018oC140%20
mb28 mb(cloud)
18oC140%20
mb28 mb(cloud)90-104oC90%8
mb6 mb
4oC90%8
mb6 mb(clear)Ahrens Fig. 4.5
Breath
Air
50-50
90-10