Camp Festus Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Festus Observatory clear sky chart from 2005-11-05 to 2017-10-31.

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
22%
14951
15%
47273
5%
14912
32%
14912
17%
32822

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
14%
750
14%
2685
2%
746
28%
746
11%
1858
January16th to endNight
18%
769
19%
2609
5%
769
35%
769
16%
1720
February1st to 15thNight
18%
704
13%
2286
5%
701
29%
701
15%
1610
February16th to endNight
17%
631
12%
2009
3%
631
29%
631
11%
1511
March1st to 15thNight
18%
720
17%
2025
5%
720
29%
720
17%
1466
March16th to endNight
20%
768
20%
2112
7%
768
31%
768
19%
1514
April1st to 15thNight
18%
583
14%
1763
5%
583
27%
583
14%
1281
April16th to endNight
20%
540
16%
1620
7%
540
28%
540
18%
1135
May1st to 15thNight
22%
540
11%
1548
5%
540
29%
540
16%
1139
May16th to endNight
19%
512
11%
1447
3%
511
27%
511
16%
1066
June1st to 15thNight
25%
360
8%
1260
5%
360
30%
360
15%
891
June16th to endNight
28%
360
6%
1260
2%
360
33%
360
15%
881
July1st to 15thNight
32%
340
11%
1190
7%
340
40%
340
22%
750
July16th to endNight
30%
446
10%
1371
8%
419
36%
419
20%
936
August1st to 15thNight
35%
539
10%
1608
6%
535
38%
535
21%
1102
August16th to endNight
36%
573
17%
1719
8%
573
43%
573
27%
1073
September1st to 15thNight
28%
588
16%
1848
6%
588
39%
588
22%
1188
September16th to endNight
33%
717
24%
1980
12%
717
43%
717
32%
1204
October1st to 15thNight
29%
720
20%
2156
8%
720
40%
720
25%
1385
October16th to endNight
21%
768
17%
2368
5%
768
32%
768
17%
1649
November1st to 15thNight
19%
723
16%
2414
6%
723
31%
723
16%
1681
November16th to endNight
23%
750
14%
2520
6%
750
33%
750
13%
1792
December1st to 15thNight
15%
750
14%
2595
3%
750
28%
750
12%
1853
December16th to endNight
13%
800
12%
2880
3%
800
24%
800
9%
2137

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
21%9%36%5%24446%32%
48485
Night
19%8%35%5%24445%34%
47435
TransparencyDay
53%211%20%10%1
48166
Night
51%311%22%10%
47273
SeeingDay
28%11%30%19%8%1
7083
Night
26%12%32%21%6%
14951

By Month

Percentage Cloud Cover NE (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
16%13%46%43435%6%31%
1253
16th to endDay
15%10%46%5%24345%37%
1614
February1st to 15thDay
11%11%46%7%26%5%47%31%
1575
16th to endDay
16%15%46%5%3443429%
1464
March1st to 15thDay
20%13%46%43423430%
1923
16th to endDay
17%11%6%6%42433433%
2112
April1st to 15thDay
22%11%47%5%2435%429%
2183
16th to endDay
26%8%25%423335%33%
2340
May1st to 15thDay
28%9%36%42323430%
2404
16th to endDay
26%8%46%5%24347%27%
2677
June1st to 15thDay
28%9%35%424446%25%
2700
16th to endDay
27%7%36%6%34446%26%
2700
July1st to 15thDay
16%6%35%5%35%5%6%8%32%
2700
16th to endDay
20%6%25%6%36%6%6%8%27%
2685
August1st to 15thDay
19%7%36%5%35%5%5%7%30%
2340
16th to endDay
14%6%26%6%35%5%5%8%35%
2483
September1st to 15thDay
18%6%25%5%24445%39%
2109
16th to endDay
18%5%24423335%46%
1980
October1st to 15thDay
18%8%25%423346%40%
1803
16th to endDay
25%8%25%42334433%
1851
November1st to 15thDay
22%9%35%5%34445%31%
1443
16th to endDay
19%10%46%424446%31%
1440
December1st to 15thDay
23%10%36%423346%30%
1362
16th to endDay
23%12%5%6%423345%27%
1344
January1st to 15thNight
16%10%46%6%345%5%5%31%
2685
16th to endNight
15%9%35%5%24446%36%
2609
February1st to 15thNight
13%11%46%6%36%5%45%31%
2285
16th to endNight
17%15%46%5%35%44328%
2009
March1st to 15thNight
20%9%35%5%25%446%32%
2013
16th to endNight
17%12%46%5%2333437%
2112
April1st to 15thNight
24%9%35%6%33345%29%
1763
16th to endNight
24%10%34313435%35%
1620
May1st to 15thNight
23%8%37%5%24445%30%
1548
16th to endNight
20%7%36%6%35%5%6%428%
1445
June1st to 15thNight
27%7%25%6%235%46%29%
1260
16th to endNight
24%7%245%35%5%5%6%30%
1260
July1st to 15thNight
14%5%25%6%345%6%7%38%
1260
16th to endNight
18%6%35%436%45%7%32%
1466
August1st to 15thNight
16%5%35%7%25%5%5%6%35%
1620
16th to endNight
13%6%244245%5%7%42%
1719
September1st to 15thNight
17%6%25%423435%43%
1848
16th to endNight
16%5%1322335%5%51%
1980
October1st to 15thNight
18%5%2433335%7%41%
2156
16th to endNight
23%7%25%5%33235%35%
2368
November1st to 15thNight
23%8%35%423346%32%
2414
16th to endNight
22%9%45%5%23345%32%
2520
December1st to 15thNight
24%9%36%5%2433432%
2595
16th to endNight
24%11%6%6%5%2434427%
2880

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
53%312%17%11%
1254
16th to endDay
50%28%21%16%
1614
February1st to 15thDay
52%212%21%9%1
1578
16th to endDay
59%27%19%9%1
1464
March1st to 15thDay
57%28%18%11%2
1934
16th to endDay
55%27%20%11%3
2112
April1st to 15thDay
58%16%16%13%2
2183
16th to endDay
54%27%17%14%3
2340
May1st to 15thDay
58%15%20%11%
2404
16th to endDay
57%410%19%7%
2681
June1st to 15thDay
59%310%16%8%1
2700
16th to endDay
58%212%16%8%
2700
July1st to 15thDay
47%316%22%10%
2541
16th to endDay
52%315%19%8%
2519
August1st to 15thDay
52%312%24%6%
2327
16th to endDay
46%316%25%8%
2483
September1st to 15thDay
46%313%25%11%
2109
16th to endDay
41%210%28%15%1
1980
October1st to 15thDay
46%312%28%9%
1803
16th to endDay
53%310%21%11%
1851
November1st to 15thDay
54%313%15%12%
1443
16th to endDay
54%314%18%9%
1440
December1st to 15thDay
57%312%19%7%
1362
16th to endDay
60%28%18%9%
1344
January1st to 15thNight
53%312%19%10%
2685
16th to endNight
48%310%24%12%
2609
February1st to 15thNight
53%310%20%11%
2286
16th to endNight
60%27%16%10%1
2009
March1st to 15thNight
53%28%20%12%1
2025
16th to endNight
52%26%21%15%2
2112
April1st to 15thNight
56%27%16%13%3
1763
16th to endNight
52%18%17%15%3
1620
May1st to 15thNight
55%39%20%9%1
1548
16th to endNight
54%411%19%8%
1447
June1st to 15thNight
55%311%20%7%1
1260
16th to endNight
54%314%19%7%
1260
July1st to 15thNight
44%414%28%7%
1190
16th to endNight
49%416%20%9%
1371
August1st to 15thNight
48%416%23%6%
1608
16th to endNight
39%318%28%8%
1719
September1st to 15thNight
44%310%27%13%
1848
16th to endNight
34%313%31%15%1
1980
October1st to 15thNight
42%211%31%11%
2156
16th to endNight
51%310%23%10%
2368
November1st to 15thNight
53%213%19%9%
2414
16th to endNight
55%312%18%8%
2520
December1st to 15thNight
56%210%23%7%
2595
16th to endNight
61%37%18%9%
2880

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%20%35%15%
60
16th to endDay
21%14%35%20%7%
151
February1st to 15thDay
19%13%37%21%7%1
236
16th to endDay
26%17%31%17%6%
220
March1st to 15thDay
33%14%28%17%5%
270
16th to endDay
28%14%30%16%7%2
288
April1st to 15thDay
32%16%27%15%7%
270
16th to endDay
33%14%25%14%8%2
270
May1st to 15thDay
39%11%23%15%7%2
360
16th to endDay
34%11%30%17%6%
519
June1st to 15thDay
36%10%27%17%5%1
495
16th to endDay
30%9%32%20%6%1
495
July1st to 15thDay
22%7%34%23%11%1
475
16th to endDay
22%6%31%29%10%
440
August1st to 15thDay
20%7%31%25%11%2
313
16th to endDay
19%9%26%25%16%2
332
September1st to 15thDay
21%9%33%23%9%2
315
16th to endDay
21%8%33%22%7%5%
314
October1st to 15thDay
25%12%28%16%12%4
271
16th to endDay
36%13%26%13%9%1
288
November1st to 15thDay
31%13%29%16%7%2
235
16th to endDay
27%15%30%19%5%1
240
December1st to 15thDay
35%11%30%14%6%
162
16th to endDay
40%18%32%6%1
64
January1st to 15thNight
23%19%34%19%3
750
16th to endNight
23%15%36%19%4
769
February1st to 15thNight
22%14%38%19%5%
704
16th to endNight
29%14%28%20%4
631
March1st to 15thNight
28%12%34%21%2
720
16th to endNight
25%16%31%20%6%
768
April1st to 15thNight
31%15%28%20%5%
583
16th to endNight
32%13%31%17%4
540
May1st to 15thNight
29%12%28%23%5%
540
16th to endNight
25%13%35%20%5%
512
June1st to 15thNight
30%6%28%26%7%
360
16th to endNight
30%5%30%25%8%
360
July1st to 15thNight
14%7%37%29%10%
340
16th to endNight
21%5%34%26%11%
446
August1st to 15thNight
21%331%28%13%1
539
16th to endNight
17%6%32%27%13%1
573
September1st to 15thNight
21%9%34%24%9%
588
16th to endNight
21%8%35%23%10%
717
October1st to 15thNight
22%9%35%21%10%
720
16th to endNight
29%13%30%19%6%
768
November1st to 15thNight
29%12%31%17%7%1
723
16th to endNight
28%14%25%22%8%1
750
December1st to 15thNight
31%14%32%16%4
750
16th to endNight
33%16%27%17%31
800
Page generated at 2017-11-01 18:23:32. Version ac04

Copyright 2017 A. Danko


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