Onondaga Cave State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Onondaga Cave State Park clear sky chart from 2005-11-05 to 2018-04-23.

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
36%
16709
22%
49539
12%
16662
45%
16662
27%
31038

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
17%
975
19%
2635
5%
970
29%
970
20%
1808
January16th to endNight
20%
1040
22%
2704
6%
1040
31%
1040
24%
1820
February1st to 15thNight
17%
929
16%
2458
4%
926
24%
926
21%
1736
February16th to endNight
17%
683
20%
2049
5%
683
29%
683
20%
1343
March1st to 15thNight
19%
663
19%
2223
7%
663
31%
663
19%
1460
March16th to endNight
21%
624
13%
2233
7%
624
30%
624
15%
1537
April1st to 15thNight
26%
584
21%
1947
10%
584
42%
584
25%
1149
April16th to endNight
29%
558
21%
1858
12%
558
43%
558
24%
1160
May1st to 15thNight
38%
540
17%
1688
12%
539
46%
539
25%
1079
May16th to endNight
43%
563
19%
1497
12%
561
49%
561
28%
1011
June1st to 15thNight
60%
540
20%
1440
14%
540
64%
540
39%
852
June16th to endNight
60%
540
23%
1440
13%
540
66%
540
43%
828
July1st to 15thNight
65%
510
19%
1360
14%
510
66%
510
41%
807
July16th to endNight
72%
564
23%
1559
20%
531
77%
531
41%
865
August1st to 15thNight
73%
539
23%
1654
26%
536
74%
536
40%
900
August16th to endNight
71%
573
24%
1910
28%
573
75%
573
38%
1018
September1st to 15thNight
62%
540
26%
1800
28%
540
64%
540
30%
1037
September16th to endNight
58%
636
31%
1940
23%
636
65%
636
36%
1094
October1st to 15thNight
47%
720
28%
2160
20%
720
54%
720
37%
1227
October16th to endNight
32%
768
29%
2304
15%
768
46%
768
31%
1337
November1st to 15thNight
33%
760
28%
2438
15%
760
48%
760
29%
1386
November16th to endNight
25%
845
25%
2600
13%
845
38%
845
26%
1606
December1st to 15thNight
22%
975
17%
2730
6%
975
32%
975
22%
1868
December16th to endNight
17%
1040
18%
2912
5%
1040
29%
1040
18%
2110

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%6%25%43445%7%42%
49974
Night
13%6%24423346%46%
49726
TransparencyDay
40%6%12%23%15%2
49664
Night
38%5%11%24%17%2
49541
SeeingDay
15%9%26%26%17%4
6533
Night
17%11%31%26%12%1
16709

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
13%7%48%4225%36%41%
1630
16th to endDay
11%9%26%433347%43%
1872
February1st to 15thDay
14%9%47%6%33436%35%
1732
16th to endDay
14%10%35%5%245%5%5%37%
1710
March1st to 15thDay
15%9%36%5%24335%40%
2077
16th to endDay
20%10%47%5%34435%30%
2341
April1st to 15thDay
13%7%1442345%6%43%
2331
16th to endDay
21%6%35%5%34446%35%
2216
May1st to 15thDay
19%5%25%42445%8%37%
2256
16th to endDay
13%436%6%35%5%5%6%39%
2617
June1st to 15thDay
9%4245%35%6%5%8%43%
2520
16th to endDay
7%213435%5%8%11%46%
2520
July1st to 15thDay
10%4245%45%5%6%9%42%
2520
16th to endDay
6%325%6%35%6%7%10%43%
2499
August1st to 15thDay
9%325%5%45%5%7%8%42%
2295
16th to endDay
9%4245%35%6%5%7%44%
2292
September1st to 15thDay
13%42442446%7%45%
2160
16th to endDay
10%425%42345%6%49%
2005
October1st to 15thDay
14%5%24423335%49%
1800
16th to endDay
12%5%23322445%52%
1920
November1st to 15thDay
13%6%14323345%50%
1750
16th to endDay
16%7%24323345%45%
1687
December1st to 15thDay
15%10%35%424346%38%
1560
16th to endDay
14%12%5%5%433346%36%
1664
January1st to 15thNight
13%7%37%5%34345%40%
2635
16th to endNight
11%9%45%424445%42%
2704
February1st to 15thNight
14%9%47%433346%38%
2449
16th to endNight
15%8%37%413345%41%
2049
March1st to 15thNight
17%9%35%5%2333441%
2223
16th to endNight
20%8%35%5%34446%33%
2233
April1st to 15thNight
12%6%24423447%47%
1947
16th to endNight
17%6%24424346%44%
1858
May1st to 15thNight
17%5%24324346%45%
1688
16th to endNight
11%435%5%345%5%7%44%
1496
June1st to 15thNight
7%31343436%8%52%
1440
16th to endNight
6%3132245%5%10%54%
1440
July1st to 15thNight
8%31342345%9%52%
1440
16th to endNight
3314425%5%6%10%52%
1666
August1st to 15thNight
42134235%5%9%54%
1664
16th to endNight
5%31443445%9%54%
1910
September1st to 15thNight
12%6%2442235%6%50%
1800
16th to endNight
8%424423446%54%
1940
October1st to 15thNight
11%314313346%54%
2160
16th to endNight
15%5%13313235%53%
2304
November1st to 15thNight
12%5%23322346%51%
2438
16th to endNight
15%8%24322335%47%
2600
December1st to 15thNight
17%9%35%423446%38%
2730
16th to endNight
17%11%36%5%24435%34%
2912

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
44%410%21%16%2
1631
16th to endDay
40%412%27%12%1
1872
February1st to 15thDay
50%411%22%11%1
1734
16th to endDay
47%49%22%12%2
1710
March1st to 15thDay
47%5%9%19%14%3
2077
16th to endDay
56%5%12%16%8%
2343
April1st to 15thDay
39%6%12%22%16%2
2331
16th to endDay
49%5%10%20%12%1
2216
May1st to 15thDay
45%6%12%22%12%
2256
16th to endDay
43%7%13%18%14%2
2621
June1st to 15thDay
35%8%12%25%16%1
2520
16th to endDay
28%7%18%25%16%3
2520
July1st to 15thDay
37%8%12%24%12%4
2371
16th to endDay
33%8%17%26%12%1
2343
August1st to 15thDay
36%9%13%23%16%1
2281
16th to endDay
36%6%14%20%16%5%
2292
September1st to 15thDay
36%7%9%23%19%3
2160
16th to endDay
34%5%8%29%18%2
2005
October1st to 15thDay
37%49%23%20%4
1800
16th to endDay
32%5%9%28%20%4
1920
November1st to 15thDay
36%410%23%19%6%
1750
16th to endDay
41%39%26%18%1
1687
December1st to 15thDay
47%5%10%23%12%
1560
16th to endDay
49%412%20%11%1
1664
January1st to 15thNight
45%5%10%21%15%1
2635
16th to endNight
42%412%23%15%1
2704
February1st to 15thNight
47%410%21%12%1
2458
16th to endNight
44%411%21%16%1
2049
March1st to 15thNight
47%39%20%15%3
2223
16th to endNight
51%5%11%21%9%
2233
April1st to 15thNight
36%5%12%26%16%3
1947
16th to endNight
41%49%27%14%1
1858
May1st to 15thNight
40%5%14%21%16%1
1689
16th to endNight
38%9%14%20%14%3
1498
June1st to 15thNight
28%6%14%29%18%2
1440
16th to endNight
23%8%15%27%20%4
1440
July1st to 15thNight
28%5%16%28%16%4
1360
16th to endNight
24%8%17%30%18%1
1559
August1st to 15thNight
24%7%15%30%19%2
1654
16th to endNight
26%6%14%24%22%5%
1910
September1st to 15thNight
34%5%8%23%22%5%
1800
16th to endNight
30%5%10%26%25%3
1940
October1st to 15thNight
30%411%24%23%5%
2160
16th to endNight
34%28%27%21%5%
2304
November1st to 15thNight
34%310%24%20%6%
2438
16th to endNight
40%38%26%20%1
2600
December1st to 15thNight
46%412%20%14%1
2730
16th to endNight
51%5%10%17%11%2
2912

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
28%17%40%11%1
135
16th to endDay
11%31%38%15%2
144
February1st to 15thDay
18%27%39%13%1
135
16th to endDay
32%22%31%11%
120
March1st to 15thDay
25%22%42%7%2
135
16th to endDay
30%22%31%14%1
199
April1st to 15thDay
21%15%36%19%6%
330
16th to endDay
24%11%31%22%7%2
289
May1st to 15thDay
20%16%29%21%9%2
354
16th to endDay
17%6%36%24%10%3
517
June1st to 15thDay
10%5%25%31%22%5%
495
16th to endDay
7%6%31%33%17%3
495
July1st to 15thDay
13%317%35%24%5%
475
16th to endDay
6%111%33%35%10%
515
August1st to 15thDay
12%13%34%29%9%
448
16th to endDay
10%16%30%31%9%
332
September1st to 15thDay
12%313%27%31%11%
315
16th to endDay
10%418%29%24%12%
272
October1st to 15thDay
16%14%23%36%8%
135
16th to endDay
13%14%34%27%9%
144
November1st to 15thDay
14%8%38%22%13%2
135
16th to endDay
24%20%31%17%7%
135
December1st to 15thDay
14%29%32%15%34
135
16th to endDay
22%21%45%9%
144
January1st to 15thNight
21%21%35%17%4
975
16th to endNight
17%21%37%21%2
1040
February1st to 15thNight
19%19%40%19%1
929
16th to endNight
23%17%38%19%1
683
March1st to 15thNight
24%15%39%17%2
663
16th to endNight
23%14%37%20%4
624
April1st to 15thNight
16%15%39%24%4
584
16th to endNight
21%8%37%23%8%
558
May1st to 15thNight
18%6%31%32%10%
540
16th to endNight
13%5%30%33%14%1
563
June1st to 15thNight
9%320%39%24%2
540
16th to endNight
7%226%39%22%2
540
July1st to 15thNight
10%15%40%28%4
510
16th to endNight
4113%40%34%5%
564
August1st to 15thNight
5%12%37%40%3
539
16th to endNight
6%114%37%34%6%
573
September1st to 15thNight
15%212%32%30%5%
540
16th to endNight
10%5%18%28%29%7%
636
October1st to 15thNight
13%5%29%28%20%2
720
16th to endNight
19%12%32%25%9%
768
November1st to 15thNight
15%12%34%25%10%
760
16th to endNight
20%15%35%21%6%
845
December1st to 15thNight
23%15%36%19%4
975
16th to endNight
25%14%40%18%1
1040
Page generated at 2018-04-24 09:03:05. Version ac04

Copyright 2018 A. Danko


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