Misti Mountain Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Misti Mountain Observatory clear sky chart from 2005-11-05 to 2017-04-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
74%
15312
36%
45603
31%
15275
79%
15275
56%
21137

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
68%
717
34%
2327
32%
716
75%
716
48%
1101
January16th to endNight
64%
768
35%
2496
32%
768
73%
768
44%
1232
February1st to 15thNight
67%
696
36%
2133
31%
696
78%
696
53%
1009
February16th to endNight
62%
632
35%
1895
34%
632
68%
632
46%
967
March1st to 15thNight
66%
720
37%
2043
31%
720
75%
720
55%
986
March16th to endNight
72%
768
36%
2112
28%
768
78%
768
59%
1005
April1st to 15thNight
61%
719
31%
1925
18%
719
69%
719
56%
953
April16th to endNight
68%
564
43%
1614
28%
564
78%
564
70%
683
May1st to 15thNight
73%
494
40%
1484
28%
494
80%
494
71%
594
May16th to endNight
71%
513
35%
1541
27%
513
76%
513
64%
645
June1st to 15thNight
78%
495
34%
1485
30%
495
80%
495
70%
611
June16th to endNight
87%
495
33%
1485
30%
495
88%
495
79%
567
July1st to 15thNight
86%
465
26%
1395
24%
465
86%
465
52%
683
July16th to endNight
84%
522
29%
1467
25%
489
85%
489
47%
758
August1st to 15thNight
87%
494
38%
1476
32%
491
87%
491
57%
683
August16th to endNight
86%
662
37%
1715
28%
662
86%
662
56%
900
September1st to 15thNight
81%
660
32%
1815
27%
660
83%
660
53%
932
September16th to endNight
82%
656
44%
1815
35%
656
87%
656
74%
776
October1st to 15thNight
77%
660
41%
1842
33%
660
83%
660
66%
834
October16th to endNight
78%
704
43%
2112
38%
704
84%
704
66%
896
November1st to 15thNight
77%
700
38%
2250
35%
700
84%
700
61%
951
November16th to endNight
73%
720
41%
2340
39%
720
82%
720
60%
979
December1st to 15thNight
72%
720
35%
2340
33%
720
78%
720
48%
1111
December16th to endNight
63%
768
35%
2496
33%
768
70%
768
41%
1281

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
3212323346%66%
46033
Night
3212213346%69%
45798
TransparencyDay
18%25%14%26%31%
45728
Night
16%26%15%28%30%
45604
SeeingDay
5%10%26%36%16%4
4984
Night
4214%35%34%8%
15326

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
4313322326%65%
1611
16th to endDay
6%313313346%62%
1728
February1st to 15thDay
3413323338%63%
1727
16th to endDay
7%423324446%56%
1579
March1st to 15thDay
331221235%6%67%
1917
16th to endDay
3312213347%66%
2112
April1st to 15thDay
2212313346%66%
2020
16th to endDay
1111211236%75%
2234
May1st to 15thDay
21312345%73%
2136
16th to endDay
122212225%74%
2221
June1st to 15thDay
11111222382%
2145
16th to endDay
11123482%
2145
July1st to 15thDay
2214424447%60%
2145
16th to endDay
4325%6%36%5%6%8%45%
2285
August1st to 15thDay
22145%25%45%7%57%
2145
16th to endDay
2214435%5%6%6%58%
2132
September1st to 15thDay
33133245%5%7%59%
1815
16th to endDay
1111112235%76%
1815
October1st to 15thDay
121232334471%
1786
16th to endDay
111212236%75%
1760
November1st to 15thDay
12223335%73%
1607
16th to endDay
4212111236%72%
1620
December1st to 15thDay
45%1232435%8%58%
1620
16th to endDay
9%412113347%58%
1728
January1st to 15thNight
4213323335%66%
2327
16th to endNight
6%313223345%62%
2496
February1st to 15thNight
3313212236%68%
2122
16th to endNight
5%323323346%60%
1895
March1st to 15thNight
221222335%7%66%
2043
16th to endNight
211222335%7%67%
2112
April1st to 15thNight
2112314336%69%
1925
16th to endNight
111112235%79%
1614
May1st to 15thNight
11112326%78%
1484
16th to endNight
2211123477%
1540
June1st to 15thNight
121233380%
1485
16th to endNight
11113483%
1485
July1st to 15thNight
121332436%8%62%
1485
16th to endNight
2223335%6%6%9%53%
1575
August1st to 15thNight
211222336%6%66%
1485
16th to endNight
223323447%64%
1715
September1st to 15thNight
221342335%6%64%
1815
16th to endNight
211112382%
1815
October1st to 15thNight
21213335%75%
1842
16th to endNight
122211235%76%
2112
November1st to 15thNight
1112213335%73%
2250
16th to endNight
311123235%73%
2340
December1st to 15thNight
5%32223346%63%
2340
16th to endNight
8%412323346%59%
2496

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
21%25%16%31%21%
1612
16th to endDay
23%26%17%30%18%
1728
February1st to 15thDay
21%26%19%26%23%
1727
16th to endDay
27%25%15%28%19%
1579
March1st to 15thDay
17%1415%35%24%
1917
16th to endDay
17%25%18%33%21%
2112
April1st to 15thDay
18%1416%29%28%
2020
16th to endDay
11%1416%30%36%
2234
May1st to 15thDay
11%25%13%31%35%
2136
16th to endDay
14%1411%30%37%
2224
June1st to 15thDay
9%126%17%62%
2145
16th to endDay
6%225%15%67%
2145
July1st to 15thDay
21%5%6%11%16%38%
2006
16th to endDay
29%6%11%18%16%17%
2130
August1st to 15thDay
23%48%15%21%26%
2130
16th to endDay
22%49%12%28%22%
2132
September1st to 15thDay
21%5%9%14%20%28%
1815
16th to endDay
12%139%26%46%
1815
October1st to 15thDay
15%25%11%28%36%
1786
16th to endDay
11%15%13%28%39%
1760
November1st to 15thDay
13%2317%32%30%
1607
16th to endDay
15%2416%29%31%
1620
December1st to 15thDay
23%38%23%23%17%
1620
16th to endDay
25%39%22%24%14%
1728
January1st to 15thNight
20%3419%34%18%
2327
16th to endNight
23%35%18%25%22%
2496
February1st to 15thNight
19%27%19%25%26%
2133
16th to endNight
23%36%16%31%18%
1895
March1st to 15thNight
17%25%14%35%23%
2043
16th to endNight
15%27%18%33%22%
2112
April1st to 15thNight
16%35%13%35%24%
1925
16th to endNight
9%1314%33%37%
1614
May1st to 15thNight
8%2415%33%35%
1485
16th to endNight
11%1412%35%34%
1541
June1st to 15thNight
9%126%18%60%
1485
16th to endNight
6%127%14%68%
1485
July1st to 15thNight
18%48%13%14%40%
1395
16th to endNight
21%6%11%21%22%16%
1467
August1st to 15thNight
15%46%15%27%29%
1476
16th to endNight
19%36%18%27%24%
1715
September1st to 15thNight
19%39%16%20%30%
1815
16th to endNight
9%128%28%49%
1815
October1st to 15thNight
12%25%13%28%37%
1842
16th to endNight
11%25%11%25%43%
2112
November1st to 15thNight
13%2415%36%28%
2250
16th to endNight
14%15%16%28%33%
2340
December1st to 15thNight
21%27%20%27%20%
2340
16th to endNight
26%38%21%28%12%
2496

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
23%10%20%34%11%1
90
16th to endDay
9%6%20%35%15%12%
96
February1st to 15thDay
7%9%33%32%14%2
242
16th to endDay
9%19%35%21%13%1
238
March1st to 15thDay
6%14%28%32%14%3
270
16th to endDay
319%31%28%13%3
288
April1st to 15thDay
8%21%29%24%12%4
269
16th to endDay
425%34%24%9%2
250
May1st to 15thDay
318%29%35%9%2
228
16th to endDay
213%34%34%12%3
266
June1st to 15thDay
27%36%37%11%4
255
16th to endDay
1322%53%12%5%
255
July1st to 15thDay
2221%50%20%4
245
16th to endDay
419%49%26%8%
271
August1st to 15thDay
4117%48%20%8%
255
16th to endDay
314%47%24%9%
268
September1st to 15thDay
3327%40%19%5%
255
16th to endDay
39%22%38%19%6%
255
October1st to 15thDay
411%29%30%19%4
226
16th to endDay
5%418%34%30%7%
96
November1st to 15thDay
3317%26%32%16%
90
16th to endDay
13%6%31%25%23%
90
December1st to 15thDay
15%20%40%31%2
90
16th to endDay
15%5%21%40%15%1
96
January1st to 15thNight
5%318%40%23%9%
720
16th to endNight
8%317%38%25%5%
768
February1st to 15thNight
6%216%41%26%5%
704
16th to endNight
6%421%41%20%4
632
March1st to 15thNight
4420%37%27%5%
720
16th to endNight
25%15%42%28%5%
768
April1st to 15thNight
36%23%36%25%4
719
16th to endNight
15%21%39%25%5%
564
May1st to 15thNight
2318%39%31%4
495
16th to endNight
1417%40%29%6%
515
June1st to 15thNight
116%41%35%5%
495
16th to endNight
8%35%47%7%
495
July1st to 15thNight
3226%56%10%
465
16th to endNight
4116%63%13%
522
August1st to 15thNight
3221%61%10%
494
16th to endNight
3218%55%18%
662
September1st to 15thNight
35%28%50%13%
660
16th to endNight
2111%30%39%14%
656
October1st to 15thNight
2313%40%33%6%
660
16th to endNight
2212%34%35%12%
704
November1st to 15thNight
2113%41%32%8%
700
16th to endNight
3316%33%31%10%
720
December1st to 15thNight
7%213%43%26%6%
720
16th to endNight
11%316%38%23%6%
768
Page generated at 2017-04-26 14:21:33. Version ac04

Copyright 2017 A. Danko


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