Click here or anywhere on the Clear Sky Clock for more information on the chart with in-depth explanations,
links to a local map of light pollution, transparency  and seeing forecasts, sun & moon data,  and much more...

(The Clear Sky Clock is brought to you courtesy of Attilla Danko and the
Canadian Meteorological Center)  Thank them!

Cover Overcast 90% 80% 70% 60% 50% 40% 30% 20% 10% Clear
Transparency Poor Below Average Average Above Average Transparent
Seeing Bad [1/5] Poor [2/5] Average [3/5] Good [4/5] Excellent [5/5]
Darkness -4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 3.5 4.0 4.5 5.0 5.2 5.4 5.6 5.8 6.0
Wind more than 45 mph 29 to 45 mph 17 to 28 mph 12 to 16 mph 6 to 11 mph 0 to 5 mph
Humidity less
than
25%
25%
to
30%
30%
to
35%
35%
to
40%
40%
to
45%
45%
to
50%
50%
to
55%
55%
to
60%
60%
to
65%
65%
to
70%
70%
to
75%
75%
to
80%
80%
to
85%
85%
to
90%
90%
to
95%
95%
to
100%
Temperature less
than
-40F
-40F
to
-31F
-30F
to
-21F
-21F
to
-12F
-12F
to
-3F
-3F
to
5F
5F
to
14F
14F
to
23F
23F
to
32F
32F
to
41F
41F
to
50F
50F
to
59F
59F
to
68F
68F
to
77F
77F
to
86F
86F
to
95F
95F
to
104F
104F
to
113F
more
than
113F