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Wolf Creek Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wolf Creek Observatory clear sky chart from 2005-11-05 to 2021-04-23.

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
50%
19967
23%
61497
16%
19924
57%
19924
27%
38121

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
27%
960
24%
3047
11%
956
43%
956
23%
1895
January16th to endNight
28%
1024
27%
3072
12%
1024
41%
1024
23%
1988
February1st to 15thNight
30%
944
23%
2832
11%
941
40%
941
23%
1839
February16th to endNight
29%
843
24%
2529
11%
843
40%
843
24%
1629
March1st to 15thNight
30%
960
23%
2873
11%
960
40%
960
27%
1809
March16th to endNight
36%
943
23%
2735
12%
943
45%
943
29%
1693
April1st to 15thNight
42%
719
26%
2397
19%
719
52%
719
30%
1372
April16th to endNight
49%
693
27%
2307
21%
693
60%
693
35%
1247
May1st to 15thNight
56%
674
24%
2106
19%
674
63%
674
35%
1212
May16th to endNight
67%
705
21%
2114
17%
705
71%
705
31%
1318
June1st to 15thNight
70%
675
15%
2025
13%
675
72%
675
26%
1337
June16th to endNight
74%
675
16%
2025
15%
675
75%
675
30%
1280
July1st to 15thNight
75%
645
10%
1935
10%
645
75%
645
24%
1319
July16th to endNight
76%
708
14%
2145
15%
675
77%
675
27%
1390
August1st to 15thNight
75%
665
11%
2206
13%
662
75%
662
23%
1477
August16th to endNight
68%
717
16%
2390
19%
717
68%
717
21%
1634
September1st to 15thNight
66%
776
17%
2351
17%
776
67%
776
25%
1542
September16th to endNight
63%
897
25%
2475
20%
897
66%
897
31%
1593
October1st to 15thNight
61%
900
33%
2475
24%
900
68%
900
43%
1383
October16th to endNight
52%
960
33%
2834
27%
960
60%
960
35%
1633
November1st to 15thNight
51%
940
28%
3056
23%
940
61%
940
33%
1694
November16th to endNight
46%
960
31%
3120
23%
960
59%
960
33%
1710
December1st to 15thNight
39%
960
25%
3120
18%
960
50%
960
26%
1887
December16th to endNight
31%
1024
20%
3328
12%
1024
41%
1024
19%
2240

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
11%5%25%5%35%5%5%7%41%
62024
Night
10%5%244345%5%7%45%
61705
TransparencyDay
40%7%11%17%17%6%
61734
Night
36%7%11%17%19%8%
61499
SeeingDay
14%8%20%23%21%11%
9840
Night
13%7%22%29%22%5%
19970

By Month

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
14%7%35%323346%44%
2207
16th to endDay
16%5%25%423445%45%
2560
February1st to 15thDay
17%7%26%5%2435%5%39%
2350
16th to endDay
16%7%25%5%34446%40%
2110
March1st to 15thDay
11%6%35%5%3445%8%41%
2405
16th to endDay
12%6%25%5%3445%7%43%
2907
April1st to 15thDay
11%5%245%2445%7%45%
2871
16th to endDay
9%3135%345%5%6%51%
2751
May1st to 15thDay
9%4245%35%45%8%46%
2833
16th to endDay
7%426%5%35%6%6%9%41%
3055
June1st to 15thDay
7%5%27%8%46%7%6%10%34%
2925
16th to endDay
6%326%6%47%8%7%10%34%
2925
July1st to 15thDay
9%5%26%7%5%8%8%8%10%26%
2925
16th to endDay
7%5%26%9%5%7%8%8%10%28%
2958
August1st to 15thDay
8%415%7%5%8%7%8%12%30%
2655
16th to endDay
11%7%36%7%46%6%7%9%30%
2868
September1st to 15thDay
9%5%35%6%47%5%5%7%39%
2582
16th to endDay
9%5%25%6%35%447%44%
2475
October1st to 15thDay
10%5%14423347%52%
2475
16th to endDay
12%413422346%53%
2441
November1st to 15thDay
12%6%24424335%51%
2122
16th to endDay
10%423423347%52%
2160
December1st to 15thDay
13%7%35%424336%45%
2160
16th to endDay
19%11%35%423345%36%
2304
January1st to 15thNight
13%8%34423435%45%
3047
16th to endNight
17%7%25%423235%44%
3072
February1st to 15thNight
15%8%25%42335%6%42%
2823
16th to endNight
14%6%24433445%44%
2529
March1st to 15thNight
11%6%36%42335%7%45%
2873
16th to endNight
10%5%25%5%33446%47%
2735
April1st to 15thNight
9%4243235%6%7%48%
2397
16th to endNight
8%32332445%7%54%
2307
May1st to 15thNight
8%3244245%5%9%50%
2105
16th to endNight
6%415%6%35%5%6%11%43%
2114
June1st to 15thNight
5%415%6%46%7%8%12%35%
2025
16th to endNight
34346%45%7%8%13%39%
2025
July1st to 15thNight
4425%7%37%8%9%12%32%
2025
16th to endNight
5%325%5%37%7%8%12%38%
2261
August1st to 15thNight
5%425%5%5%6%9%9%12%33%
2218
16th to endNight
7%5%36%6%46%6%6%9%36%
2390
September1st to 15thNight
9%425%6%36%6%7%8%39%
2351
16th to endNight
9%5%25%435%5%6%7%44%
2475
October1st to 15thNight
7%413323347%57%
2475
16th to endNight
12%6%1332223456%
2834
November1st to 15thNight
11%413323446%54%
3056
16th to endNight
10%423323345%55%
3120
December1st to 15thNight
14%5%25%423346%46%
3120
16th to endNight
18%8%35%434446%37%
3328

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%37%15%25%7%
2208
16th to endDay
40%45%15%25%8%
2560
February1st to 15thDay
45%37%14%21%6%
2352
16th to endDay
45%45%14%19%10%
2110
March1st to 15thDay
40%5%9%16%20%9%
2405
16th to endDay
39%5%10%17%20%6%
2908
April1st to 15thDay
36%5%8%20%19%8%
2871
16th to endDay
31%6%9%20%25%6%
2751
May1st to 15thDay
34%7%9%17%24%5%
2833
16th to endDay
37%9%12%22%16%3
3059
June1st to 15thDay
42%10%13%20%10%2
2925
16th to endDay
40%10%17%18%11%1
2925
July1st to 15thDay
45%15%18%13%5%1
2786
16th to endDay
45%12%19%17%4
2811
August1st to 15thDay
40%12%20%17%7%
2643
16th to endDay
47%10%14%14%9%2
2868
September1st to 15thDay
41%9%15%15%13%5%
2582
16th to endDay
38%6%10%18%20%4
2475
October1st to 15thDay
32%410%18%23%10%
2475
16th to endDay
32%36%16%26%15%
2441
November1st to 15thDay
35%36%16%25%11%
2122
16th to endDay
31%48%17%24%13%
2160
December1st to 15thDay
40%48%18%20%7%
2160
16th to endDay
50%36%19%14%6%
2304
January1st to 15thNight
41%35%17%23%8%
3047
16th to endNight
43%35%13%24%9%
3072
February1st to 15thNight
42%46%16%19%9%
2832
16th to endNight
41%46%14%19%13%
2529
March1st to 15thNight
38%49%15%20%10%
2873
16th to endNight
36%5%10%17%21%8%
2735
April1st to 15thNight
32%5%10%17%22%11%
2397
16th to endNight
28%5%9%24%22%9%
2307
May1st to 15thNight
30%6%11%19%24%8%
2106
16th to endNight
33%9%15%20%16%5%
2116
June1st to 15thNight
36%11%17%16%14%1
2025
16th to endNight
32%11%21%21%10%2
2025
July1st to 15thNight
36%15%26%14%6%1
1935
16th to endNight
32%14%23%22%6%
2145
August1st to 15thNight
35%15%21%18%6%2
2206
16th to endNight
41%12%16%13%13%2
2390
September1st to 15thNight
38%10%14%17%12%6%
2351
16th to endNight
36%8%10%19%19%6%
2475
October1st to 15thNight
27%410%19%24%13%
2475
16th to endNight
32%3413%27%17%
2834
November1st to 15thNight
31%46%17%26%13%
3056
16th to endNight
30%46%18%24%15%
3120
December1st to 15thNight
38%49%17%23%6%
3120
16th to endNight
47%5%6%17%17%6%
3328

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%19%32%18%5%2
270
16th to endDay
21%23%35%14%3
288
February1st to 15thDay
31%21%29%15%2
270
16th to endDay
19%21%38%19%
240
March1st to 15thDay
20%20%43%9%5%
275
16th to endDay
18%14%32%25%8%
544
April1st to 15thDay
16%13%32%21%14%1
510
16th to endDay
13%11%27%25%15%5%
467
May1st to 15thDay
10%7%23%27%23%7%
468
16th to endDay
11%117%30%21%17%
523
June1st to 15thDay
10%211%30%26%17%
495
16th to endDay
8%211%24%29%24%
495
July1st to 15thDay
8%1423%37%25%
485
16th to endDay
5%15%20%39%26%
518
August1st to 15thDay
9%15%19%34%29%
478
16th to endDay
12%6%22%35%22%
524
September1st to 15thDay
9%210%25%31%19%
495
16th to endDay
11%112%26%33%14%
494
October1st to 15thDay
12%220%28%29%7%
495
16th to endDay
19%9%23%23%21%4
408
November1st to 15thDay
22%10%31%25%8%1
270
16th to endDay
10%12%34%28%11%1
270
December1st to 15thDay
23%17%37%17%4
270
16th to endDay
26%18%29%19%5%
288
January1st to 15thNight
18%15%32%25%6%
960
16th to endNight
21%14%32%26%5%
1024
February1st to 15thNight
21%12%32%29%5%
944
16th to endNight
18%15%32%28%4
843
March1st to 15thNight
14%15%36%26%7%
960
16th to endNight
13%13%33%26%11%
943
April1st to 15thNight
13%8%31%30%15%1
719
16th to endNight
9%8%28%34%18%
693
May1st to 15thNight
9%422%34%25%3
675
16th to endNight
7%115%34%35%6%
707
June1st to 15thNight
8%110%31%39%9%
675
16th to endNight
417%27%45%14%
675
July1st to 15thNight
6%5%23%45%18%
645
16th to endNight
6%1425%43%18%
708
August1st to 15thNight
7%322%46%19%
665
16th to endNight
8%17%26%41%14%
717
September1st to 15thNight
11%9%26%38%13%
776
16th to endNight
11%114%29%36%6%
897
October1st to 15thNight
10%120%34%28%3
900
16th to endNight
15%6%20%29%24%3
960
November1st to 15thNight
13%5%24%34%18%3
940
16th to endNight
12%11%25%34%14%1
960
December1st to 15thNight
17%10%28%31%10%
960
16th to endNight
23%12%28%25%9%
1024
Page generated at 2021-04-24 10:54:45. Version ac04

Copyright 2021 A. Danko


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