Taylor Oaks Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Taylor Oaks Observatory clear sky chart from 2005-11-06 to 2024-01-16.

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
45%
24294
22%
74411
14%
24241
53%
24241
26%
46707

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 10thNight
25%
759
23%
2459
9%
757
43%
757
21%
1493
January11th to 20thNight
29%
744
25%
2417
13%
744
45%
744
22%
1486
January21st to endNight
28%
792
28%
2574
13%
792
46%
792
25%
1538
February1st to 10thNight
29%
720
21%
2340
11%
720
43%
720
23%
1449
February11th to 20thNight
19%
702
23%
2107
8%
699
36%
699
21%
1373
February21st to endNight
23%
592
25%
1729
10%
592
40%
592
24%
1120
March1st to 10thNight
32%
720
26%
1980
14%
720
43%
720
30%
1225
March11th to 20thNight
28%
720
22%
1980
10%
720
39%
720
25%
1300
March21st to endNight
30%
792
20%
2178
8%
792
40%
792
23%
1450
April1st to 10thNight
33%
720
24%
1980
11%
720
44%
720
30%
1213
April11th to 20thNight
41%
711
25%
1787
11%
711
49%
711
35%
1107
April21st to endNight
44%
604
28%
1684
15%
604
51%
604
35%
1006
May1st to 10thNight
44%
540
20%
1620
9%
540
51%
540
31%
962
May11th to 20thNight
46%
531
15%
1593
8%
531
51%
531
23%
1078
May21st to endNight
60%
582
18%
1744
15%
582
61%
582
27%
1138
June1st to 10thNight
60%
540
15%
1620
12%
540
62%
540
24%
1109
June11th to 20thNight
59%
540
14%
1620
12%
540
61%
540
24%
1106
June21st to endNight
63%
540
13%
1620
11%
540
65%
540
24%
1091
July1st to 10thNight
65%
525
11%
1575
9%
525
65%
525
22%
1106
July11th to 20thNight
70%
522
12%
1566
10%
522
71%
522
25%
1039
July21st to endNight
65%
591
14%
1672
11%
558
67%
558
24%
1153
August1st to 10thNight
64%
537
13%
1600
12%
534
64%
534
24%
1091
August11th to 20thNight
61%
534
16%
1598
13%
534
62%
534
22%
1097
August21st to endNight
63%
737
16%
1925
11%
737
64%
737
24%
1390
September1st to 10thNight
67%
720
20%
1962
16%
720
68%
720
31%
1255
September11th to 20thNight
60%
720
21%
1980
18%
720
62%
720
27%
1328
September21st to endNight
53%
720
20%
1980
15%
720
58%
720
26%
1333
October1st to 10thNight
56%
720
26%
2084
23%
720
62%
720
34%
1253
October11th to 20thNight
48%
720
30%
2160
24%
720
59%
720
33%
1255
October21st to endNight
49%
792
32%
2376
23%
792
62%
792
35%
1345
November1st to 10thNight
48%
740
29%
2221
22%
740
58%
740
34%
1273
November11th to 20thNight
40%
760
28%
2410
19%
760
53%
760
29%
1393
November21st to endNight
44%
760
28%
2470
19%
760
56%
760
29%
1430
December1st to 10thNight
34%
760
23%
2470
14%
760
46%
760
20%
1592
December11th to 20thNight
39%
759
27%
2924
20%
758
50%
758
24%
1665
December21st to endNight
31%
828
17%
4406
14%
817
43%
817
14%
2465

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%25%5%35%5%6%8%43%
74957
Night
14%6%25%5%345%5%7%44%
74863
TransparencyDay
39%7%11%20%19%5%
74680
Night
38%6%11%19%20%6%
74659
SeeingDay
16%9%24%24%18%7%
14164
Night
16%9%23%30%19%3
24307

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 10thDay
17%6%25%434445%46%
1706
11th to 20thDay
16%8%35%434346%44%
1671
21st to endDay
16%6%2442444448%
1782
February1st to 10thDay
16%7%25%5%345%5%8%41%
1620
11th to 20thDay
21%5%23424445%46%
1735
21st to endDay
20%7%35%5%34445%41%
1525
March1st to 10thDay
16%424333446%52%
1980
11th to 20thDay
17%5%35%435%5%6%7%40%
1980
21st to endDay
17%6%36%435%5%46%41%
2178
April1st to 10thDay
11%5%243245%6%8%50%
1980
11th to 20thDay
13%5%25%435%447%48%
2120
21st to endDay
12%4244345%47%50%
2290
May1st to 10thDay
9%426%5%36%5%6%8%45%
2340
11th to 20thDay
13%5%346%45%5%6%7%41%
2301
21st to endDay
11%6%26%6%45%5%6%9%40%
2531
June1st to 10thDay
10%5%25%6%46%6%7%11%38%
2340
11th to 20thDay
8%5%35%5%46%6%7%10%42%
2340
21st to endDay
6%425%7%5%7%7%7%11%40%
2340
July1st to 10thDay
7%5%38%8%46%7%8%10%33%
2340
11th to 20thDay
8%5%36%7%5%6%7%9%11%32%
2340
21st to endDay
6%5%36%7%5%7%7%8%12%33%
2547
August1st to 10thDay
11%5%36%6%5%7%8%8%10%32%
2327
11th to 20thDay
13%6%26%7%5%7%7%7%10%30%
2303
21st to endDay
10%6%36%7%5%6%6%7%10%35%
2412
September1st to 10thDay
8%425%6%46%6%7%10%42%
1994
11th to 20thDay
12%6%36%5%35%6%5%9%41%
1980
21st to endDay
17%6%36%5%3445%6%41%
1980
October1st to 10thDay
14%424323445%53%
1874
11th to 20thDay
14%5%23323335%57%
1800
21st to endDay
13%424423346%56%
1980
November1st to 10thDay
14%5%24423335%56%
1857
11th to 20thDay
14%5%2332335%6%53%
1767
21st to endDay
16%5%243245%46%50%
1710
December1st to 10thDay
18%8%3444435%7%39%
1710
11th to 20thDay
17%5%2432235%6%51%
2153
21st to endDay
18%7%244245%46%43%
3124
January1st to 10thNight
18%6%25%423345%47%
2459
11th to 20thNight
17%6%3442445%6%45%
2417
21st to endNight
16%7%24433345%49%
2574
February1st to 10thNight
16%7%25%434445%46%
2340
11th to 20thNight
21%6%35%433445%44%
2107
21st to endNight
17%6%35%5%335%5%6%43%
1729
March1st to 10thNight
15%6%35%323347%49%
1980
11th to 20thNight
15%6%35%5%3446%8%42%
1980
21st to endNight
14%7%36%6%345%5%6%42%
2178
April1st to 10thNight
13%5%245%34447%50%
1980
11th to 20thNight
12%5%24424448%51%
1787
21st to endNight
12%5%145%34448%51%
1684
May1st to 10thNight
10%4245%35%5%5%8%49%
1620
11th to 20thNight
12%6%36%6%5%5%5%7%8%36%
1592
21st to endNight
11%5%36%5%35%6%6%9%41%
1744
June1st to 10thNight
10%6%35%6%5%8%7%7%10%35%
1620
11th to 20thNight
11%5%35%5%5%6%7%7%11%36%
1620
21st to endNight
7%6%36%7%47%6%8%12%35%
1620
July1st to 10thNight
8%6%37%7%5%7%7%8%12%30%
1620
11th to 20thNight
8%5%26%6%37%7%9%12%35%
1620
21st to endNight
6%5%36%7%5%7%8%8%11%33%
1771
August1st to 10thNight
11%6%25%6%46%6%8%13%32%
1611
11th to 20thNight
10%8%36%7%46%7%7%9%34%
1598
21st to endNight
10%5%37%6%46%8%8%11%32%
1925
September1st to 10thNight
9%425%7%346%8%9%43%
1962
11th to 20thNight
13%5%36%6%35%5%6%8%40%
1980
21st to endNight
17%6%35%6%35%45%8%39%
1980
October1st to 10thNight
15%5%13323445%53%
2084
11th to 20thNight
14%434423347%53%
2160
21st to endNight
13%5%24333335%57%
2376
November1st to 10thNight
13%5%24322336%55%
2221
11th to 20thNight
12%5%25%434445%53%
2410
21st to endNight
14%43443346%6%49%
2470
December1st to 10thNight
19%7%36%5%34345%43%
2470
11th to 20thNight
18%5%24423335%52%
3042
21st to endNight
20%5%25%43445%7%43%
4532

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 10thDay
40%5%7%18%23%6%
1707
11th to 20thDay
44%37%18%22%5%
1671
21st to endDay
39%45%21%24%7%
1782
February1st to 10thDay
41%410%21%18%5%
1620
11th to 20thDay
41%5%6%19%24%5%
1745
21st to endDay
46%48%15%19%8%
1525
March1st to 10thDay
35%47%21%24%9%
1980
11th to 20thDay
43%6%10%18%17%6%
1980
21st to endDay
44%6%9%19%19%3
2178
April1st to 10thDay
32%5%10%21%26%6%
1980
11th to 20thDay
36%5%9%19%21%10%
2120
21st to endDay
33%6%11%22%23%4
2290
May1st to 10thDay
35%8%13%22%20%3
2340
11th to 20thDay
39%9%15%20%16%2
2305
21st to endDay
39%8%12%23%15%2
2531
June1st to 10thDay
38%9%14%26%11%2
2340
11th to 20thDay
35%10%18%22%14%2
2340
21st to endDay
35%12%15%22%14%2
2340
July1st to 10thDay
41%12%17%17%11%3
2275
11th to 20thDay
41%11%20%19%8%1
2271
21st to endDay
39%11%19%22%9%1
2405
August1st to 10thDay
44%10%17%20%8%1
2314
11th to 20thDay
47%10%16%17%10%1
2303
21st to endDay
42%9%17%19%9%3
2412
September1st to 10thDay
35%9%14%19%19%4
1994
11th to 20thDay
40%8%10%17%22%4
1980
21st to endDay
44%5%8%20%16%6%
1980
October1st to 10thDay
35%48%20%27%6%
1874
11th to 20thDay
32%39%23%24%8%
1800
21st to endDay
31%37%20%29%10%
1980
November1st to 10thDay
32%36%18%30%9%
1857
11th to 20thDay
31%47%22%27%8%
1767
21st to endDay
36%5%8%21%22%8%
1710
December1st to 10thDay
45%5%7%20%19%4
1710
11th to 20thDay
36%27%21%24%10%
2150
21st to endDay
42%47%21%22%3
3124
January1st to 10thNight
41%38%18%24%7%
2459
11th to 20thNight
40%49%16%24%6%
2417
21st to endNight
39%35%21%25%7%
2574
February1st to 10thNight
41%48%20%20%7%
2340
11th to 20thNight
45%35%17%23%7%
2108
21st to endNight
40%5%9%18%19%8%
1729
March1st to 10thNight
37%48%16%24%11%
1980
11th to 20thNight
41%5%11%15%21%7%
1980
21st to endNight
42%6%10%18%19%5%
2178
April1st to 10thNight
35%49%19%26%7%
1980
11th to 20thNight
33%49%23%22%9%
1787
21st to endNight
33%5%9%26%22%5%
1684
May1st to 10thNight
32%7%15%23%19%4
1620
11th to 20thNight
42%9%13%18%17%1
1593
21st to endNight
37%9%12%24%14%2
1745
June1st to 10thNight
42%10%15%20%12%2
1620
11th to 20thNight
40%11%15%20%11%2
1620
21st to endNight
38%13%17%17%11%3
1620
July1st to 10thNight
42%12%20%15%8%3
1575
11th to 20thNight
37%12%24%17%7%3
1566
21st to endNight
40%12%19%19%9%1
1672
August1st to 10thNight
41%10%22%19%7%1
1600
11th to 20thNight
43%10%19%16%10%1
1598
21st to endNight
42%12%16%19%8%3
1925
September1st to 10thNight
35%9%16%18%17%6%
1962
11th to 20thNight
40%9%12%16%21%2
1980
21st to endNight
43%6%11%17%18%6%
1980
October1st to 10thNight
34%5%9%20%26%6%
2084
11th to 20thNight
33%48%22%23%10%
2160
21st to endNight
32%36%20%28%12%
2376
November1st to 10thNight
33%36%17%28%13%
2221
11th to 20thNight
34%5%6%17%26%13%
2410
21st to endNight
35%45%21%27%7%
2470
December1st to 10thNight
44%5%8%17%21%6%
2470
11th to 20thNight
37%38%17%25%10%
3044
21st to endNight
42%38%21%23%3
4532

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 10thDay
22%20%39%17%2
270
11th to 20thDay
25%23%31%16%5%
257
21st to endDay
22%22%39%13%3
264
February1st to 10thDay
23%20%39%12%5%
240
11th to 20thDay
33%20%38%8%1
240
21st to endDay
28%21%35%14%2
243
March1st to 10thDay
22%16%35%19%7%
420
11th to 20thDay
23%16%38%17%5%1
420
21st to endDay
24%16%36%18%6%1
462
April1st to 10thDay
19%16%34%20%10%1
420
11th to 20thDay
17%15%32%21%12%3
412
21st to endDay
17%10%29%25%14%5%
420
May1st to 10thDay
12%14%35%21%14%4
423
11th to 20thDay
17%5%21%28%22%8%
447
21st to endDay
15%5%18%26%24%13%
485
June1st to 10thDay
10%318%33%26%10%
450
11th to 20thDay
10%419%26%29%12%
450
21st to endDay
9%216%34%28%11%
450
July1st to 10thDay
9%29%30%29%20%
445
11th to 20thDay
9%29%31%33%16%
444
21st to endDay
6%111%33%35%14%
488
August1st to 10thDay
13%316%29%24%16%
446
11th to 20thDay
15%39%25%30%17%
439
21st to endDay
12%213%29%27%17%
495
September1st to 10thDay
9%312%28%33%15%
450
11th to 20thDay
15%414%26%28%13%
450
21st to endDay
18%6%18%28%25%5%
450
October1st to 10thDay
17%5%22%25%22%8%
450
11th to 20thDay
12%10%24%25%23%5%
450
21st to endDay
16%10%24%26%19%4
495
November1st to 10thDay
20%8%26%26%17%3
455
11th to 20thDay
18%12%36%25%6%2
327
21st to endDay
15%11%35%26%11%2
270
December1st to 10thDay
26%12%40%16%5%
270
11th to 20thDay
22%13%34%22%8%1
270
21st to endDay
27%16%34%14%7%3
297
January1st to 10thNight
21%18%30%25%6%
760
11th to 20thNight
21%13%31%29%5%
744
21st to endNight
20%14%35%27%4
792
February1st to 10thNight
20%13%35%28%4
720
11th to 20thNight
25%16%37%21%1
703
21st to endNight
20%16%36%24%4
592
March1st to 10thNight
18%12%36%29%5%
720
11th to 20thNight
19%14%34%24%8%1
720
21st to endNight
19%14%31%28%7%
792
April1st to 10thNight
17%16%32%26%10%
720
11th to 20thNight
14%14%28%31%13%1
711
21st to endNight
14%7%30%33%15%
604
May1st to 10thNight
10%9%31%36%14%
540
11th to 20thNight
13%5%24%36%20%1
531
21st to endNight
13%314%34%34%2
584
June1st to 10thNight
11%317%38%27%4
540
11th to 20thNight
13%415%29%31%9%
540
21st to endNight
9%312%37%33%5%
540
July1st to 10thNight
11%110%32%37%8%
525
11th to 20thNight
9%27%32%42%8%
522
21st to endNight
7%213%30%42%6%
591
August1st to 10thNight
14%29%29%38%8%
537
11th to 20thNight
13%39%29%40%7%
534
21st to endNight
12%210%28%43%6%
737
September1st to 10thNight
10%210%31%41%6%
720
11th to 20thNight
14%411%28%38%5%
720
21st to endNight
19%5%15%32%26%3
720
October1st to 10thNight
16%5%18%30%25%6%
720
11th to 20thNight
17%6%23%29%22%2
720
21st to endNight
15%10%21%32%19%3
792
November1st to 10thNight
15%7%25%31%18%3
740
11th to 20thNight
14%11%30%33%11%1
760
21st to endNight
15%10%26%34%13%1
760
December1st to 10thNight
21%12%26%34%6%1
760
11th to 20thNight
20%9%26%33%11%1
760
21st to endNight
25%13%25%29%8%
836
Page generated at 2024-01-13 19:28:28. Version ac07

Copyright 2024 Attilla Danko


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