Split Mountain Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Split Mountain Campground clear sky chart from 2005-11-05 to 2017-09-15.

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
67%
15911
22%
46902
20%
15875
69%
15875
36%
27505

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%
766
16%
2377
16%
766
70%
766
30%
1464
January16th to endNight
64%
768
18%
2496
20%
768
66%
768
25%
1608
February1st to 15thNight
65%
697
15%
2288
16%
697
68%
697
27%
1447
February16th to endNight
59%
632
19%
1964
17%
632
64%
632
28%
1234
March1st to 15thNight
66%
720
21%
1980
20%
720
67%
720
38%
1194
March16th to endNight
57%
768
21%
2112
16%
768
61%
768
33%
1342
April1st to 15thNight
53%
571
17%
1830
16%
571
56%
571
27%
1117
April16th to endNight
51%
540
22%
1707
18%
540
56%
540
30%
1016
May1st to 15thNight
56%
540
20%
1620
16%
540
59%
540
32%
974
May16th to endNight
60%
561
20%
1541
15%
561
63%
561
35%
937
June1st to 15thNight
68%
540
23%
1440
20%
540
70%
540
45%
817
June16th to endNight
75%
540
31%
1440
28%
540
79%
540
61%
717
July1st to 15thNight
80%
510
20%
1410
18%
510
81%
510
44%
790
July16th to endNight
82%
564
24%
1593
24%
531
82%
531
45%
844
August1st to 15thNight
77%
539
22%
1611
21%
536
78%
536
43%
847
August16th to endNight
83%
573
34%
1813
33%
573
84%
573
46%
906
September1st to 15thNight
77%
555
30%
1815
31%
555
80%
555
44%
902
September16th to endNight
77%
656
34%
1826
29%
656
78%
656
53%
936
October1st to 15thNight
71%
660
30%
1980
25%
660
73%
660
44%
1049
October16th to endNight
73%
704
31%
2112
25%
704
76%
704
43%
1131
November1st to 15thNight
69%
747
27%
2219
23%
747
72%
747
41%
1225
November16th to endNight
70%
900
25%
2520
21%
900
72%
900
45%
1399
December1st to 15thNight
64%
900
13%
2520
11%
900
65%
900
31%
1626
December16th to endNight
54%
960
11%
2688
9%
960
56%
960
20%
1983

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
44244345%6%9%49%
47823
Night
5%5%2442445%8%50%
47090
TransparencyDay
29%6%14%22%18%8%
47512
Night
31%5%14%23%17%7%
46902
SeeingDay
7%6%19%34%25%5%
5745
Night
8%213%44%26%4
15925

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%36%6%46%7%9%13%30%
1570
16th to endDay
5%8%46%7%5%7%6%6%11%29%
1728
February1st to 15thDay
35%37%6%5%6%7%9%14%29%
1575
16th to endDay
5%8%36%5%36%45%8%40%
1506
March1st to 15thDay
47%25%425%5%6%10%45%
1980
16th to endDay
45%35%5%35%6%8%9%43%
2112
April1st to 15thDay
47%26%5%25%45%8%47%
2117
16th to endDay
5%7%25%6%35%5%5%8%44%
2252
May1st to 15thDay
5%425%436%5%6%9%47%
2331
16th to endDay
5%4245%2446%8%50%
2570
June1st to 15thDay
421232446%9%57%
2520
16th to endDay
212212446%70%
2520
July1st to 15thDay
33134346%7%9%52%
2463
16th to endDay
3313435%5%7%9%51%
2467
August1st to 15thDay
3213435%6%7%8%51%
2340
16th to endDay
31123145%5%8%61%
2387
September1st to 15thDay
321321345%7%63%
2132
16th to endDay
5%211322235%69%
1803
October1st to 15thDay
6%41232345%7%57%
1650
16th to endDay
5%2133335%5%9%55%
1760
November1st to 15thDay
4413424448%58%
1624
16th to endDay
342442346%9%52%
1440
December1st to 15thDay
5%8%36%6%45%5%7%9%35%
1440
16th to endDay
8%9%48%9%5%7%6%7%9%23%
1536
January1st to 15thNight
5%7%25%425%5%5%9%45%
2377
16th to endNight
6%8%37%43445%11%39%
2496
February1st to 15thNight
36%26%5%35%5%6%9%45%
2277
16th to endNight
39%45%5%2445%8%45%
1964
March1st to 15thNight
46%35%425%449%50%
1980
16th to endNight
7%7%35%434447%47%
2112
April1st to 15thNight
7%8%25%425%45%8%44%
1830
16th to endNight
8%6%344235%6%7%46%
1707
May1st to 15thNight
7%6%234335%5%9%48%
1619
16th to endNight
7%4235%25%5%6%8%48%
1540
June1st to 15thNight
33132245%7%7%56%
1440
16th to endNight
222313346%68%
1440
July1st to 15thNight
2213436%5%8%9%52%
1494
16th to endNight
12134246%7%10%53%
1701
August1st to 15thNight
1315%5%2436%9%54%
1620
16th to endNight
2134245%6%9%59%
1813
September1st to 15thNight
421332445%6%59%
1815
16th to endNight
5%312222345%66%
1826
October1st to 15thNight
7%413422346%59%
1980
16th to endNight
6%42222345%6%58%
2112
November1st to 15thNight
4425%41445%8%54%
2219
16th to endNight
342431335%8%58%
2520
December1st to 15thNight
5%7%36%4345%5%8%45%
2520
16th to endNight
9%7%48%7%46%5%6%8%31%
2688

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
40%15%25%15%4
1571
16th to endDay
46%11%19%16%5%
1728
February1st to 15thDay
41%12%21%17%5%
1575
16th to endDay
42%6%17%26%7%
1506
March1st to 15thDay
33%7%19%25%12%1
1980
16th to endDay
34%5%17%30%9%2
2112
April1st to 15thDay
34%5%15%23%17%3
2117
16th to endDay
35%6%12%26%16%3
2252
May1st to 15thDay
31%5%12%24%22%4
2331
16th to endDay
29%5%11%26%22%4
2573
June1st to 15thDay
22%49%18%30%15%
2520
16th to endDay
12%25%11%30%37%
2520
July1st to 15thDay
24%5%11%16%18%23%
2318
16th to endDay
25%5%11%18%19%19%
2312
August1st to 15thDay
25%6%11%20%17%18%
2325
16th to endDay
18%49%23%28%14%
2387
September1st to 15thDay
19%49%20%26%18%
2132
16th to endDay
16%37%29%34%8%
1803
October1st to 15thDay
24%415%33%20%2
1650
16th to endDay
24%6%16%34%17%1
1760
November1st to 15thDay
25%5%18%32%16%1
1624
16th to endDay
27%6%25%29%10%
1440
December1st to 15thDay
42%10%30%13%2
1440
16th to endDay
52%13%17%12%4
1536
January1st to 15thNight
35%7%25%24%5%
2377
16th to endNight
39%8%20%21%9%1
2496
February1st to 15thNight
35%10%20%22%9%
2288
16th to endNight
37%6%16%25%12%1
1964
March1st to 15thNight
32%418%29%12%2
1980
16th to endNight
37%412%29%12%3
2112
April1st to 15thNight
37%5%11%21%19%4
1830
16th to endNight
34%6%12%24%19%2
1707
May1st to 15thNight
34%5%11%20%24%4
1620
16th to endNight
33%5%12%23%21%3
1541
June1st to 15thNight
24%5%9%15%25%18%
1440
16th to endNight
16%239%27%40%
1440
July1st to 15thNight
23%6%8%17%18%25%
1410
16th to endNight
22%6%11%20%18%21%
1593
August1st to 15thNight
25%414%18%18%19%
1611
16th to endNight
20%6%7%17%30%17%
1813
September1st to 15thNight
22%47%17%26%20%
1815
16th to endNight
20%37%22%30%15%
1826
October1st to 15thNight
25%39%31%23%5%
1980
16th to endNight
24%5%10%32%25%2
2112
November1st to 15thNight
27%414%29%21%2
2219
16th to endNight
25%418%35%15%1
2520
December1st to 15thNight
37%7%25%24%5%
2520
16th to endNight
48%9%20%16%4
2688

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
21%17%38%23%7%
90
16th to endDay
17%1335%38%4
96
February1st to 15thDay
11%450%24%10%
90
16th to endDay
11%113%47%21%4
120
March1st to 15thDay
10%6%15%42%22%2
270
16th to endDay
11%11%27%35%12%
288
April1st to 15thDay
7%17%31%26%15%2
269
16th to endDay
13%18%29%26%10%
270
May1st to 15thDay
8%17%30%24%16%2
288
16th to endDay
10%8%22%29%23%6%
471
June1st to 15thDay
6%8%22%30%27%4
495
16th to endDay
3419%34%33%5%
495
July1st to 15thDay
5%318%29%33%9%
422
16th to endDay
3315%46%27%3
327
August1st to 15thDay
6%222%42%22%3
315
16th to endDay
3114%34%35%10%
332
September1st to 15thDay
36%17%33%28%10%
312
16th to endDay
7%216%24%38%10%
243
October1st to 15thDay
2316%34%34%8%
90
16th to endDay
12%313%39%28%3
96
November1st to 15thDay
6%114%36%27%13%
90
16th to endDay
7%430%44%10%3
90
December1st to 15thDay
7%214%64%7%3
90
16th to endDay
14%110%48%21%3
96
January1st to 15thNight
8%110%51%23%4
771
16th to endNight
11%110%49%21%4
768
February1st to 15thNight
7%13%56%19%2
704
16th to endNight
6%318%53%16%
632
March1st to 15thNight
6%214%50%23%1
720
16th to endNight
9%420%45%19%
768
April1st to 15thNight
13%6%21%39%17%1
571
16th to endNight
11%8%23%35%19%3
540
May1st to 15thNight
10%422%36%21%3
540
16th to endNight
10%5%16%36%25%5%
563
June1st to 15thNight
5%416%48%22%1
540
16th to endNight
4114%47%29%2
540
July1st to 15thNight
318%35%45%4
510
16th to endNight
3432%51%7%
564
August1st to 15thNight
36%42%43%3
539
16th to endNight
36%33%46%9%
573
September1st to 15thNight
5%18%38%38%7%
555
16th to endNight
6%110%30%38%13%
656
October1st to 15thNight
8%112%43%28%5%
660
16th to endNight
8%211%41%29%6%
704
November1st to 15thNight
7%212%45%29%2
747
16th to endNight
6%213%50%23%3
900
December1st to 15thNight
10%113%58%14%1
900
16th to endNight
14%213%48%18%2
960
Page generated at 2017-09-15 22:58:32. Version ac04

Copyright 2017 A. Danko


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