UBar Camp and Retreat Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the UBar Camp and Retreat Center clear sky chart from 2005-11-05 to 2018-02-13.

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
48%
16064
28%
48788
18%
16017
57%
16017
36%
27343

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
35%
974
30%
2522
12%
970
46%
970
36%
1536
January16th to endNight
38%
894
33%
2558
15%
894
51%
894
35%
1464
February1st to 15thNight
35%
752
29%
2251
13%
746
48%
746
33%
1265
February16th to endNight
23%
632
30%
1894
8%
632
42%
632
33%
1051
March1st to 15thNight
32%
606
29%
2046
14%
606
48%
606
30%
1160
March16th to endNight
30%
576
26%
2112
16%
576
44%
576
29%
1149
April1st to 15thNight
25%
539
25%
1947
11%
539
44%
539
29%
1081
April16th to endNight
27%
540
27%
1761
14%
540
47%
540
29%
1027
May1st to 15thNight
30%
539
23%
1620
13%
539
44%
539
30%
984
May16th to endNight
42%
562
24%
1684
16%
561
55%
561
33%
1005
June1st to 15thNight
63%
540
22%
1620
21%
540
70%
540
53%
790
June16th to endNight
65%
540
23%
1620
24%
540
69%
540
41%
889
July1st to 15thNight
72%
510
21%
1530
21%
510
76%
510
41%
846
July16th to endNight
81%
564
26%
1594
30%
531
84%
531
47%
822
August1st to 15thNight
86%
539
28%
1757
35%
536
86%
536
52%
807
August16th to endNight
75%
573
21%
1925
25%
573
77%
573
32%
1113
September1st to 15thNight
75%
540
20%
1980
25%
540
77%
540
33%
1085
September16th to endNight
65%
537
24%
1980
26%
537
68%
537
28%
1156
October1st to 15thNight
66%
540
32%
1980
30%
540
71%
540
40%
960
October16th to endNight
56%
726
39%
2262
25%
726
66%
726
49%
1090
November1st to 15thNight
49%
851
28%
2371
14%
851
56%
851
40%
1340
November16th to endNight
47%
975
34%
2535
16%
975
56%
975
42%
1456
December1st to 15thNight
41%
975
30%
2535
15%
975
48%
975
35%
1557
December16th to endNight
35%
1040
26%
2704
11%
1040
44%
1040
33%
1710

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
12%5%24424447%48%
49245
Night
10%413323347%54%
48989
Cloud CoverDay
11%5%24424447%48%
49243
Night
9%5%23323347%54%
48989
TransparencyDay
36%39%20%19%9%
48943
Night
30%311%21%20%12%
48794
SeeingDay
13%5%20%33%21%5%
5821
Night
12%6%28%35%15%1
16067

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
13%5%24423335%52%
1746
16th to endDay
12%5%2322334456%
2028
February1st to 15thDay
12%6%22323346%54%
1870
16th to endDay
11%5%23223436%54%
1580
March1st to 15thDay
17%6%13212246%50%
1914
16th to endDay
15%423323435%51%
2112
April1st to 15thDay
13%5%14423446%48%
1998
16th to endDay
12%6%25%423246%48%
2198
May1st to 15thDay
16%6%25%5%34446%40%
2331
16th to endDay
19%6%3432445%6%39%
2430
June1st to 15thDay
5%315%5%345%5%8%51%
2340
16th to endDay
10%425%6%35%6%6%9%38%
2340
July1st to 15thDay
10%425%5%35%5%5%8%41%
2340
16th to endDay
7%2245%35%5%6%9%46%
2466
August1st to 15thDay
311343446%8%56%
2190
16th to endDay
11%425%5%45%5%5%10%39%
2276
September1st to 15thDay
11%6%25%7%35%45%7%40%
1980
16th to endDay
13%425%6%345%5%6%42%
1980
October1st to 15thDay
10%5%14423346%52%
1980
16th to endDay
8%412222235%64%
1950
November1st to 15thDay
13%6%2442335%6%46%
1814
16th to endDay
11%313313335%58%
1755
December1st to 15thDay
17%6%24313246%48%
1755
16th to endDay
13%8%24322435%48%
1872
January1st to 15thNight
14%5%23312235%54%
2522
16th to endNight
12%5%23323345%54%
2558
February1st to 15thNight
11%5%13323235%56%
2246
16th to endNight
10%424313447%54%
1894
March1st to 15thNight
13%6%14313346%51%
2046
16th to endNight
12%5%14223336%53%
2112
April1st to 15thNight
10%425%32435%5%52%
1947
16th to endNight
11%5%24324347%50%
1761
May1st to 15thNight
13%324423446%49%
1619
16th to endNight
12%42441335%8%48%
1683
June1st to 15thNight
321221335%9%63%
1620
16th to endNight
6%31333435%10%54%
1620
July1st to 15thNight
6%31433445%10%53%
1620
16th to endNight
43122145%6%10%57%
1702
August1st to 15thNight
221221235%10%63%
1767
16th to endNight
7%413435%5%6%10%47%
1925
September1st to 15thNight
8%5%134245%5%9%50%
1980
16th to endNight
10%5%25%43435%6%47%
1980
October1st to 15thNight
9%313212247%60%
1980
16th to endNight
7%21332223467%
2262
November1st to 15thNight
10%413312346%56%
2371
16th to endNight
11%5%12212235%61%
2535
December1st to 15thNight
14%6%23312236%51%
2535
16th to endNight
12%6%25%412345%50%
2704

Percentage Cloud Cover SE (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
12%6%34323335%52%
1746
16th to endDay
11%5%1322334456%
2028
February1st to 15thDay
11%6%13322346%54%
1870
16th to endDay
10%5%23323446%54%
1580
March1st to 15thDay
16%6%14212336%50%
1914
16th to endDay
14%5%23323345%51%
2110
April1st to 15thDay
12%5%14423446%48%
1998
16th to endDay
11%6%26%423346%48%
2198
May1st to 15thDay
14%7%25%5%35%45%6%39%
2331
16th to endDay
16%7%35%42445%6%40%
2430
June1st to 15thDay
43145%35%45%9%51%
2340
16th to endDay
9%5%25%6%36%6%6%10%38%
2340
July1st to 15thDay
9%435%6%35%5%6%9%40%
2340
16th to endDay
7%3245%35%6%7%8%46%
2466
August1st to 15thDay
22135%3445%9%56%
2190
16th to endDay
10%5%25%6%35%46%9%39%
2276
September1st to 15thDay
9%6%27%6%35%45%8%39%
1980
16th to endDay
12%5%25%6%345%5%7%41%
1980
October1st to 15thDay
9%5%145%22346%52%
1980
16th to endDay
7%313222235%64%
1950
November1st to 15thDay
12%6%2442345%7%46%
1814
16th to endDay
10%413313235%58%
1755
December1st to 15thDay
16%7%24312246%48%
1755
16th to endDay
12%9%24313435%48%
1872
January1st to 15thNight
13%5%23312235%54%
2522
16th to endNight
11%5%23323345%54%
2558
February1st to 15thNight
11%5%14323235%56%
2246
16th to endNight
9%433323346%54%
1894
March1st to 15thNight
12%6%24323346%51%
2046
16th to endNight
10%6%24223336%53%
2112
April1st to 15thNight
9%5%25%42345%5%52%
1947
16th to endNight
9%6%24324447%50%
1761
May1st to 15thNight
11%5%24423446%48%
1619
16th to endNight
10%6%2442335%7%48%
1683
June1st to 15thNight
321221335%10%63%
1620
16th to endNight
6%31333445%10%53%
1620
July1st to 15thNight
5%31333445%10%53%
1620
16th to endNight
4332145%5%10%57%
1702
August1st to 15thNight
221221236%10%63%
1767
16th to endNight
6%414435%5%6%10%46%
1925
September1st to 15thNight
7%5%1432445%8%50%
1980
16th to endNight
9%6%25%43445%6%47%
1980
October1st to 15thNight
8%31322235%6%60%
1980
16th to endNight
6%21331223468%
2262
November1st to 15thNight
10%423322346%56%
2371
16th to endNight
9%5%13312235%61%
2535
December1st to 15thNight
13%6%24312236%51%
2535
16th to endNight
12%6%35%423345%49%
2704

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
35%2419%23%14%
1747
16th to endDay
31%25%14%28%17%
2028
February1st to 15thDay
32%28%15%22%19%
1871
16th to endDay
32%25%18%24%16%
1580
March1st to 15thDay
36%38%16%19%15%
1914
16th to endDay
36%37%19%21%11%
2112
April1st to 15thDay
37%37%15%19%15%
1998
16th to endDay
38%27%20%18%12%
2198
May1st to 15thDay
44%49%14%19%7%
2331
16th to endDay
45%49%18%17%4
2434
June1st to 15thDay
30%411%25%22%5%
2340
16th to endDay
40%6%12%20%15%4
2340
July1st to 15thDay
37%5%14%26%13%1
2201
16th to endDay
29%6%19%30%12%1
2311
August1st to 15thDay
23%5%15%37%17%1
2176
16th to endDay
40%5%15%25%9%2
2276
September1st to 15thDay
42%5%9%21%17%4
1980
16th to endDay
40%5%10%18%16%8%
1980
October1st to 15thDay
33%310%20%21%10%
1980
16th to endDay
24%2416%30%21%
1950
November1st to 15thDay
38%28%20%18%10%
1814
16th to endDay
30%25%15%23%21%
1755
December1st to 15thDay
39%27%16%24%10%
1755
16th to endDay
38%27%16%23%11%
1872
January1st to 15thNight
34%1417%22%18%
2522
16th to endNight
32%25%16%24%19%
2558
February1st to 15thNight
32%26%13%22%22%
2256
16th to endNight
31%26%16%25%17%
1894
March1st to 15thNight
35%28%14%21%17%
2046
16th to endNight
33%39%19%20%13%
2112
April1st to 15thNight
34%39%17%17%18%
1947
16th to endNight
36%310%18%18%13%
1761
May1st to 15thNight
35%411%20%16%10%
1620
16th to endNight
34%414%25%15%4
1685
June1st to 15thNight
18%416%30%26%4
1620
16th to endNight
27%417%28%17%4
1620
July1st to 15thNight
25%6%20%31%13%1
1530
16th to endNight
20%6%24%32%14%1
1594
August1st to 15thNight
16%5%19%39%18%
1757
16th to endNight
31%7%22%25%10%2
1925
September1st to 15thNight
30%6%16%24%18%5%
1980
16th to endNight
36%5%13%18%17%8%
1980
October1st to 15thNight
25%314%26%18%11%
1980
16th to endNight
21%15%19%28%23%
2262
November1st to 15thNight
29%29%24%21%12%
2371
16th to endNight
28%25%17%22%22%
2535
December1st to 15thNight
35%27%18%22%13%
2535
16th to endNight
37%26%16%22%14%
2704

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
17%10%40%25%5%
135
16th to endDay
17%9%41%24%6%
144
February1st to 15thDay
15%13%35%26%7%
126
16th to endDay
17%9%39%29%21
81
March1st to 15thDay
23%8%40%16%11%
90
16th to endDay
11%8%37%32%9%1
96
April1st to 15thDay
11%19%45%17%31
117
16th to endDay
13%15%42%21%7%
308
May1st to 15thDay
18%10%39%26%5%
468
16th to endDay
25%5%27%30%11%
517
June1st to 15thDay
6%217%47%23%2
495
16th to endDay
10%213%40%27%6%
495
July1st to 15thDay
9%29%41%31%5%
475
16th to endDay
6%1437%38%12%
515
August1st to 15thDay
4238%41%12%
345
16th to endDay
13%26%35%27%14%
316
September1st to 15thDay
3131%45%17%
135
16th to endDay
16%226%43%11%
135
October1st to 15thDay
8%437%36%13%
135
16th to endDay
11%6%23%34%21%3
144
November1st to 15thDay
28%221%34%8%4
135
16th to endDay
17%9%30%24%13%5%
135
December1st to 15thDay
20%429%27%14%3
135
16th to endDay
28%9%31%23%6%
144
January1st to 15thNight
17%9%32%31%8%
975
16th to endNight
14%9%34%33%8%
894
February1st to 15thNight
15%13%32%30%7%
752
16th to endNight
13%12%48%23%1
632
March1st to 15thNight
16%9%37%31%4
606
16th to endNight
14%11%41%28%4
576
April1st to 15thNight
12%11%48%25%2
539
16th to endNight
12%10%46%25%5%
540
May1st to 15thNight
14%7%44%27%5%
540
16th to endNight
12%335%35%11%
563
June1st to 15thNight
3128%49%16%
540
16th to endNight
6%120%47%21%2
540
July1st to 15thNight
6%11%49%30%1
510
16th to endNight
4456%28%4
564
August1st to 15thNight
2444%41%5%
539
16th to endNight
7%15%43%37%5%
573
September1st to 15thNight
9%16%38%39%4
540
16th to endNight
11%19%41%33%2
537
October1st to 15thNight
9%215%40%28%3
540
16th to endNight
7%427%34%22%2
726
November1st to 15thNight
12%5%28%34%17%1
851
16th to endNight
13%7%28%33%15%1
975
December1st to 15thNight
17%8%29%34%9%
975
16th to endNight
16%9%33%32%7%
1040
Page generated at 2018-02-13 19:46:07. Version ac04

Copyright 2018 A. Danko


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