HUMIDITY AND CLOUD COVER FORECAST FOR LA SILLA, CHILE. Forecast period starting at 00:00 on 2015.08.04 (day 216 of 2015). Forecast Period | HUMIDITY | CLOUD COVER (UTC) | Avg UTH(%) Sig UTH PWV(mm) | %Total %Opaque %Transp. T.Index | CldAdj 2015.08.04 00h | 55.4 26.7 5.91 | 69 46 23 n/a | 0 2015.08.04 00h-03h | 51.9 24.8 5.78 | 47 25 22 n/a | 0 2015.08.04 03h-06h | 34.5 20.5 5.16 | 15 10 5 n/a | 0 2015.08.04 06h-09h | 75.3 25.1 n/a | 83 61 22 n/a | + 2015.08.04 09h-12h | 87.4 15.8 n/a | 98 80 17 n/a | +