The HauntedStar Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The HauntedStar Observatory clear sky chart from 2005-11-05 to 2017-09-22.

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
55%
15686
25%
47118
20%
15642
61%
15642
33%
27855

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
39%
898
29%
2327
14%
895
48%
895
34%
1445
January16th to endNight
38%
960
28%
2496
13%
960
47%
960
35%
1568
February1st to 15thNight
37%
876
21%
2284
9%
872
43%
872
30%
1493
February16th to endNight
36%
598
28%
1860
13%
598
47%
598
31%
1090
March1st to 15thNight
39%
540
22%
1980
17%
540
47%
540
23%
1203
March16th to endNight
44%
576
20%
2112
19%
576
50%
576
23%
1317
April1st to 15thNight
46%
539
25%
1806
20%
539
57%
539
32%
1013
April16th to endNight
46%
540
25%
1800
19%
540
58%
540
31%
1046
May1st to 15thNight
56%
539
19%
1728
18%
539
61%
539
27%
1067
May16th to endNight
64%
562
21%
1684
21%
561
67%
561
32%
1027
June1st to 15thNight
79%
540
26%
1482
24%
540
82%
540
49%
806
June16th to endNight
79%
540
25%
1556
25%
540
80%
540
44%
836
July1st to 15thNight
77%
510
18%
1530
19%
510
78%
510
34%
920
July16th to endNight
85%
564
24%
1594
27%
531
86%
531
43%
864
August1st to 15thNight
80%
539
24%
1641
28%
536
80%
536
40%
882
August16th to endNight
78%
573
24%
1910
29%
573
78%
573
33%
1082
September1st to 15thNight
72%
540
26%
1800
30%
540
73%
540
33%
1024
September16th to endNight
74%
560
33%
1888
33%
560
77%
560
38%
1008
October1st to 15thNight
66%
660
32%
1980
27%
660
68%
660
39%
1114
October16th to endNight
58%
704
35%
2112
26%
704
64%
704
40%
1141
November1st to 15thNight
56%
700
31%
2100
24%
700
63%
700
37%
1168
November16th to endNight
46%
768
28%
2355
21%
768
54%
768
31%
1390
December1st to 15thNight
43%
900
21%
2520
13%
900
49%
900
29%
1638
December16th to endNight
41%
960
24%
2573
13%
960
48%
960
27%
1713

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
13%5%2443445%7%44%
47733
Night
12%423323347%51%
47314
TransparencyDay
38%6%10%22%17%4
47433
Night
33%5%10%23%21%5%
47119
SeeingDay
12%313%25%29%15%
5742
Night
14%419%35%23%2
15690

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
20%42342322350%
1611
16th to endDay
14%7%24322336%48%
1728
February1st to 15thDay
17%7%2332223349%
1578
16th to endDay
18%7%34422335%42%
1622
March1st to 15thDay
19%5%235%24435%43%
1980
16th to endDay
19%5%35%433345%41%
2110
April1st to 15thDay
15%5%24423347%45%
2142
16th to endDay
16%6%24425%447%40%
2160
May1st to 15thDay
16%6%25%5%3445%6%38%
2220
16th to endDay
11%5%25%6%47%6%6%7%37%
2430
June1st to 15thDay
6%325%5%35%6%6%8%44%
2469
16th to endDay
5%325%5%35%6%7%10%44%
2394
July1st to 15thDay
7%437%6%46%7%6%9%35%
2340
16th to endDay
5%4245%46%6%6%10%43%
2466
August1st to 15thDay
8%315%5%46%5%7%9%41%
2307
16th to endDay
8%425%5%36%5%7%8%42%
2292
September1st to 15thDay
13%5%243345%5%7%45%
2160
16th to endDay
11%31442435%6%50%
1870
October1st to 15thDay
14%5%24323336%51%
1650
16th to endDay
14%21321334457%
1760
November1st to 15thDay
12%423213336%56%
1758
16th to endDay
18%5%23322245%48%
1599
December1st to 15thDay
18%5%23323346%46%
1440
16th to endDay
21%5%335%2333443%
1647
January1st to 15thNight
18%413312236%52%
2327
16th to endNight
15%5%2432233452%
2496
February1st to 15thNight
17%5%24313345%47%
2274
16th to endNight
15%423323336%52%
1860
March1st to 15thNight
19%6%24323246%44%
1980
16th to endNight
17%6%245%13435%44%
2112
April1st to 15thNight
10%424423347%52%
1806
16th to endNight
13%424324447%48%
1800
May1st to 15thNight
14%5%2342445%7%45%
1727
16th to endNight
9%42443345%9%46%
1683
June1st to 15thNight
321331346%9%58%
1482
16th to endNight
32243235%5%10%56%
1556
July1st to 15thNight
3325%435%6%8%10%45%
1620
16th to endNight
3112435%47%10%55%
1702
August1st to 15thNight
5%2134245%6%10%53%
1651
16th to endNight
6%3135%35%5%7%11%45%
1910
September1st to 15thNight
9%5%14423447%52%
1800
16th to endNight
7%31332345%7%55%
1888
October1st to 15thNight
11%32323337%56%
1980
16th to endNight
13%21231322462%
2112
November1st to 15thNight
9%414423337%56%
2100
16th to endNight
17%5%23313235%52%
2355
December1st to 15thNight
19%6%2442333446%
2520
16th to endNight
19%6%2432332445%
2573

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%35%25%19%5%
1612
16th to endDay
37%37%26%19%3
1728
February1st to 15thDay
40%39%25%16%4
1579
16th to endDay
43%47%20%18%4
1622
March1st to 15thDay
43%49%18%17%6%
1980
16th to endDay
45%410%24%13%1
2112
April1st to 15thDay
39%5%9%21%20%4
2142
16th to endDay
42%6%9%20%18%3
2160
May1st to 15thDay
45%7%9%16%18%2
2220
16th to endDay
42%9%12%21%12%1
2434
June1st to 15thDay
34%7%12%26%18%
2469
16th to endDay
31%8%14%24%17%2
2394
July1st to 15thDay
40%9%13%24%10%1
2201
16th to endDay
31%9%16%26%14%1
2311
August1st to 15thDay
34%8%15%24%15%1
2293
16th to endDay
36%9%15%20%14%4
2292
September1st to 15thDay
37%7%10%19%17%8%
2160
16th to endDay
33%5%9%21%25%5%
1870
October1st to 15thDay
35%47%21%23%7%
1650
16th to endDay
29%3425%26%9%
1760
November1st to 15thDay
30%38%27%22%8%
1758
16th to endDay
38%36%20%24%5%
1599
December1st to 15thDay
39%311%23%17%4
1440
16th to endDay
45%39%21%15%4
1647
January1st to 15thNight
35%26%23%27%4
2327
16th to endNight
36%37%24%22%6%
2496
February1st to 15thNight
39%48%24%18%5%
2284
16th to endNight
35%38%26%18%7%
1860
March1st to 15thNight
41%410%16%20%7%
1980
16th to endNight
42%49%22%17%2
2112
April1st to 15thNight
32%49%24%21%8%
1806
16th to endNight
35%410%23%22%3
1800
May1st to 15thNight
37%6%10%21%18%5%
1728
16th to endNight
33%7%17%23%16%1
1685
June1st to 15thNight
20%6%12%31%25%2
1482
16th to endNight
24%5%14%25%23%5%
1556
July1st to 15thNight
29%10%17%24%16%1
1530
16th to endNight
20%10%16%31%18%2
1594
August1st to 15thNight
25%5%17%29%18%2
1641
16th to endNight
29%8%16%24%17%3
1910
September1st to 15thNight
31%6%9%23%20%8%
1800
16th to endNight
27%5%8%23%26%8%
1888
October1st to 15thNight
29%49%21%23%11%
1980
16th to endNight
28%3421%31%10%
2112
November1st to 15thNight
29%37%24%24%10%
2100
16th to endNight
35%36%21%26%6%
2355
December1st to 15thNight
41%39%21%18%5%
2520
16th to endNight
44%27%22%18%4
2573

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
25%8%20%28%14%2
90
16th to endDay
14%14%36%25%9%
96
February1st to 15thDay
14%11%35%27%10%1
90
16th to endDay
12%11%39%24%11%1
81
March1st to 15thDay
23%8%36%22%8%
90
16th to endDay
14%13%25%25%21%
96
April1st to 15thDay
18%8%25%30%15%1
261
16th to endDay
24%220%30%19%3
270
May1st to 15thDay
18%6%19%29%21%4
357
16th to endDay
12%317%34%24%8%
517
June1st to 15thDay
7%110%22%37%20%
495
16th to endDay
5%19%27%37%18%
495
July1st to 15thDay
8%18%28%33%19%
475
16th to endDay
5%316%38%35%
515
August1st to 15thDay
10%15%23%38%21%
460
16th to endDay
13%412%43%26%
332
September1st to 15thDay
13%5%17%39%24%
315
16th to endDay
10%5%22%40%20%
155
October1st to 15thDay
10%114%28%32%13%
90
16th to endDay
17%27%38%20%13%
96
November1st to 15thDay
12%116%35%26%7%
90
16th to endDay
31%7%25%14%18%2
90
December1st to 15thDay
21%423%27%17%5%
90
16th to endDay
26%8%31%28%6%
96
January1st to 15thNight
21%8%27%34%8%
900
16th to endNight
18%5%32%38%4
960
February1st to 15thNight
19%6%30%38%4
876
16th to endNight
17%8%35%35%3
598
March1st to 15thNight
19%6%27%40%4
540
16th to endNight
18%427%37%11%
576
April1st to 15thNight
12%6%28%41%10%
539
16th to endNight
13%5%28%37%14%
540
May1st to 15thNight
15%217%43%19%
540
16th to endNight
9%15%40%29%3
563
June1st to 15thNight
47%37%44%5%
540
16th to endNight
37%30%52%5%
540
July1st to 15thNight
46%30%51%6%
510
16th to endNight
3322%57%13%
564
August1st to 15thNight
5%5%27%52%8%
539
16th to endNight
8%425%55%6%
573
September1st to 15thNight
11%6%26%50%4
540
16th to endNight
7%19%33%42%5%
560
October1st to 15thNight
13%113%34%32%3
660
16th to endNight
14%418%39%21%2
704
November1st to 15thNight
11%6%20%40%19%1
700
16th to endNight
19%8%22%32%16%
768
December1st to 15thNight
23%5%23%38%8%
900
16th to endNight
23%7%22%39%7%
960
Page generated at 2017-09-23 05:43:34. Version ac04

Copyright 2017 A. Danko


The HauntedStar Observatory Clear Sky Chart | Charts Home