Stoneman Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stoneman Lake clear sky chart from 2005-11-05 to 2017-04-07.

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
52%
15071
32%
45400
20%
15027
64%
15027
43%
22872

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
41%
720
30%
2327
18%
716
57%
716
35%
1189
January16th to endNight
40%
768
34%
2496
20%
768
59%
768
33%
1334
February1st to 15thNight
45%
703
31%
2226
19%
700
62%
700
40%
1090
February16th to endNight
33%
632
34%
1879
19%
632
52%
632
36%
989
March1st to 15thNight
42%
720
36%
1980
18%
720
59%
720
43%
1041
March16th to endNight
45%
768
34%
2112
16%
768
61%
768
47%
1072
April1st to 15thNight
36%
654
29%
1857
12%
654
51%
654
38%
971
April16th to endNight
42%
495
38%
1554
18%
495
62%
495
48%
660
May1st to 15thNight
44%
495
36%
1484
19%
494
59%
494
50%
674
May16th to endNight
48%
513
32%
1540
17%
513
59%
513
52%
688
June1st to 15thNight
50%
495
34%
1485
22%
495
60%
495
63%
636
June16th to endNight
67%
495
31%
1485
26%
495
71%
495
66%
627
July1st to 15thNight
73%
465
19%
1395
15%
465
76%
465
37%
796
July16th to endNight
73%
522
17%
1467
15%
489
74%
489
32%
883
August1st to 15thNight
77%
494
26%
1476
22%
491
78%
491
38%
818
August16th to endNight
79%
544
28%
1668
26%
544
81%
544
40%
904
September1st to 15thNight
73%
660
29%
1815
22%
660
77%
660
45%
1025
September16th to endNight
71%
656
40%
1815
27%
656
79%
656
63%
829
October1st to 15thNight
54%
660
37%
1908
22%
660
68%
660
52%
908
October16th to endNight
58%
704
40%
2112
26%
704
71%
704
51%
972
November1st to 15thNight
50%
700
35%
2143
19%
700
67%
700
47%
1027
November16th to endNight
46%
720
37%
2340
24%
720
64%
720
43%
1083
December1st to 15thNight
46%
720
31%
2340
20%
720
62%
720
35%
1216
December16th to endNight
36%
768
29%
2496
19%
768
50%
768
27%
1440

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
4424424446%58%
45830
Night
3423323446%62%
45596
TransparencyDay
25%47%17%28%17%
45525
Night
21%37%18%28%19%
45402
SeeingDay
10%19%30%28%9%1
4749
Night
6%12%24%30%21%4
15074

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
46%1332324462%
1611
16th to endDay
7%8%22313337%56%
1728
February1st to 15thDay
28%34213346%57%
1634
16th to endDay
38%24423347%54%
1594
March1st to 15thDay
36%2332345%5%60%
1980
16th to endDay
45%23232346%62%
2112
April1st to 15thDay
3414324446%61%
1906
16th to endDay
35%13322335%66%
2073
May1st to 15thDay
3323313346%64%
2136
16th to endDay
4313323335%64%
2221
June1st to 15thDay
111121223477%
2145
16th to endDay
111222423473%
2145
July1st to 15thDay
5%325%6%5%7%6%7%7%42%
2145
16th to endDay
8%5%37%7%47%8%8%8%29%
2285
August1st to 15thDay
7%5%36%7%46%5%6%6%39%
2145
16th to endDay
6%426%5%46%6%7%8%41%
2179
September1st to 15thDay
7%425%7%35%5%5%6%45%
1815
16th to endDay
323323345%68%
1815
October1st to 15thDay
331332432467%
1719
16th to endDay
3313212235%69%
1760
November1st to 15thDay
231321345%5%66%
1714
16th to endDay
441221224468%
1620
December1st to 15thDay
5%9%2332235%6%56%
1620
16th to endDay
6%9%35%42343450%
1728
January1st to 15thNight
36%34313445%59%
2327
16th to endNight
5%8%24222345%57%
2496
February1st to 15thNight
27%23213345%63%
2215
16th to endNight
47%2232345%7%58%
1879
March1st to 15thNight
35%1231235%6%63%
1980
16th to endNight
3212223446%66%
2112
April1st to 15thNight
3423323346%61%
1857
16th to endNight
111222223474%
1554
May1st to 15thNight
2112223335%71%
1484
16th to endNight
221121333472%
1540
June1st to 15thNight
22211123377%
1485
16th to endNight
111221222379%
1485
July1st to 15thNight
3314425%7%7%9%49%
1485
16th to endNight
43245%46%8%10%10%38%
1575
August1st to 15thNight
3323445%6%6%9%49%
1485
16th to endNight
23144346%7%11%49%
1668
September1st to 15thNight
332443445%6%57%
1815
16th to endNight
211111223475%
1815
October1st to 15thNight
3112213345%70%
1908
16th to endNight
1322212335%71%
2112
November1st to 15thNight
3313214445%66%
2143
16th to endNight
35%22222235%67%
2340
December1st to 15thNight
47%2322445%6%57%
2340
16th to endNight
5%8%35%424345%51%
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
24%37%20%32%11%
1612
16th to endDay
28%27%17%31%11%
1728
February1st to 15thDay
27%27%24%20%17%
1634
16th to endDay
28%37%21%27%11%
1594
March1st to 15thDay
23%25%18%35%13%
1980
16th to endDay
23%27%22%31%12%
2112
April1st to 15thDay
23%26%20%33%13%
1906
16th to endDay
20%25%17%37%16%
2073
May1st to 15thDay
19%36%18%33%18%
2136
16th to endDay
21%35%14%38%16%
2224
June1st to 15thDay
11%139%30%42%
2145
16th to endDay
13%338%26%43%
2145
July1st to 15thDay
34%8%11%14%12%18%
2006
16th to endDay
41%13%15%14%12%1
2130
August1st to 15thDay
40%7%10%14%15%11%
2130
16th to endDay
34%10%12%16%19%6%
2179
September1st to 15thDay
36%7%8%15%17%15%
1815
16th to endDay
17%2416%34%23%
1815
October1st to 15thDay
20%3415%31%24%
1719
16th to endDay
17%25%15%38%21%
1760
November1st to 15thDay
18%35%21%31%18%
1714
16th to endDay
19%2418%32%22%
1620
December1st to 15thDay
28%38%24%25%9%
1620
16th to endDay
36%28%21%24%6%
1728
January1st to 15thNight
25%37%20%30%12%
2327
16th to endNight
29%2417%30%14%
2496
February1st to 15thNight
22%29%21%23%19%
2226
16th to endNight
25%37%21%27%14%
1879
March1st to 15thNight
22%2419%36%13%
1980
16th to endNight
18%48%23%31%13%
2112
April1st to 15thNight
22%36%18%33%14%
1857
16th to endNight
13%15%20%37%20%
1554
May1st to 15thNight
14%36%22%30%22%
1485
16th to endNight
14%25%17%38%21%
1541
June1st to 15thNight
11%128%28%46%
1485
16th to endNight
11%136%21%54%
1485
July1st to 15thNight
26%8%13%14%17%19%
1395
16th to endNight
31%8%20%20%14%4
1467
August1st to 15thNight
26%7%12%19%20%13%
1476
16th to endNight
24%7%15%21%21%9%
1668
September1st to 15thNight
25%5%13%18%20%16%
1815
16th to endNight
12%25%16%36%27%
1815
October1st to 15thNight
16%26%20%26%26%
1908
16th to endNight
15%36%13%34%27%
2112
November1st to 15thNight
18%36%20%32%17%
2143
16th to endNight
20%15%15%31%24%
2340
December1st to 15thNight
26%38%21%25%14%
2340
16th to endNight
34%47%20%24%8%
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
30%23%27%13%41
90
16th to endDay
18%25%25%16%12%2
96
February1st to 15thDay
6%29%33%16%12%2
149
16th to endDay
17%33%29%15%3
238
March1st to 15thDay
11%28%31%19%6%2
270
16th to endDay
11%29%31%19%42
288
April1st to 15thDay
14%33%32%10%5%2
234
16th to endDay
11%36%33%13%4
210
May1st to 15thDay
11%27%39%18%2
228
16th to endDay
9%25%33%24%6%
266
June1st to 15thDay
5%23%42%21%6%1
255
16th to endDay
28%38%41%8%
255
July1st to 15thDay
7%6%35%43%7%
245
16th to endDay
8%224%44%16%4
271
August1st to 15thDay
10%219%49%14%3
255
16th to endDay
9%223%41%19%2
268
September1st to 15thDay
11%7%30%38%10%1
255
16th to endDay
8%13%25%38%10%2
255
October1st to 15thDay
5%28%30%24%8%3
159
16th to endDay
10%12%30%33%12%1
96
November1st to 15thDay
10%11%28%30%14%5%
90
16th to endDay
8%31%28%24%6%
90
December1st to 15thDay
6%17%38%20%15%1
90
16th to endDay
23%17%25%27%5%1
96
January1st to 15thNight
9%16%27%25%15%4
720
16th to endNight
12%14%27%27%14%2
768
February1st to 15thNight
6%15%27%33%13%2
704
16th to endNight
9%19%34%24%9%2
632
March1st to 15thNight
7%18%28%28%14%2
720
16th to endNight
5%15%30%30%15%2
768
April1st to 15thNight
6%22%30%28%11%1
654
16th to endNight
222%30%29%11%3
495
May1st to 15thNight
215%33%32%15%
495
16th to endNight
313%30%29%19%2
515
June1st to 15thNight
36%37%35%16%1
495
16th to endNight
1322%44%26%2
495
July1st to 15thNight
411%40%39%4
465
16th to endNight
46%35%43%10%
522
August1st to 15thNight
6%6%30%43%12%
494
16th to endNight
316%30%46%12%
544
September1st to 15thNight
414%29%43%8%
660
16th to endNight
38%14%28%35%9%
656
October1st to 15thNight
312%26%32%20%4
660
16th to endNight
311%22%30%24%7%
704
November1st to 15thNight
412%28%30%18%5%
700
16th to endNight
7%15%26%25%18%6%
720
December1st to 15thNight
10%13%25%30%17%1
720
16th to endNight
12%16%29%26%11%3
768
Page generated at 2017-04-08 02:35:14. Version ac04

Copyright 2017 A. Danko


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