Hickory Knolls Discovery Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hickory Knolls Discovery Center 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
38%
15993
18%
46898
11%
15952
45%
15952
24%
31243

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
20%
900
15%
2506
4%
895
29%
895
19%
1816
January16th to endNight
22%
960
13%
2646
5%
960
29%
960
16%
1981
February1st to 15thNight
22%
806
14%
2217
4%
806
29%
806
18%
1578
February16th to endNight
27%
631
18%
1893
7%
631
37%
631
19%
1317
March1st to 15thNight
27%
720
13%
2160
8%
720
33%
720
18%
1514
March16th to endNight
30%
613
15%
2008
11%
613
37%
613
18%
1400
April1st to 15thNight
29%
539
15%
1797
10%
539
39%
539
20%
1201
April16th to endNight
34%
540
19%
1743
10%
540
44%
540
23%
1167
May1st to 15thNight
37%
540
15%
1584
7%
540
44%
540
22%
1100
May16th to endNight
49%
561
18%
1498
10%
561
54%
561
31%
969
June1st to 15thNight
52%
540
16%
1440
10%
540
56%
540
35%
903
June16th to endNight
49%
540
16%
1440
9%
540
54%
540
31%
950
July1st to 15thNight
63%
510
18%
1360
12%
510
66%
510
41%
813
July16th to endNight
70%
564
22%
1417
16%
531
74%
531
43%
825
August1st to 15thNight
77%
539
21%
1574
20%
536
78%
536
41%
863
August16th to endNight
67%
573
21%
1910
22%
573
71%
573
36%
1052
September1st to 15thNight
64%
540
29%
1800
29%
540
69%
540
37%
953
September16th to endNight
56%
682
26%
1889
19%
682
61%
682
35%
1147
October1st to 15thNight
48%
660
26%
1908
19%
660
54%
660
32%
1152
October16th to endNight
30%
704
18%
2233
11%
704
39%
704
21%
1452
November1st to 15thNight
34%
700
23%
2276
16%
700
44%
700
24%
1399
November16th to endNight
27%
771
16%
2391
8%
771
36%
771
19%
1631
December1st to 15thNight
23%
900
13%
2520
5%
900
29%
900
17%
1879
December16th to endNight
16%
960
11%
2688
3%
960
24%
960
12%
2181

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%7%36%5%35%45%7%36%
47995
Night
14%7%35%424446%40%
47066
Cloud CoverDay
14%8%35%5%3445%7%36%
48004
Night
14%7%35%42445%6%40%
47071
TransparencyDay
45%6%12%21%11%1
47681
Night
43%5%11%22%13%2
46898
SeeingDay
15%8%27%26%15%6%
6001
Night
17%8%29%30%12%1
15998

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
14%12%5%7%6%35%5%5%6%27%
1432
16th to endDay
13%14%6%10%6%34345%26%
1575
February1st to 15thDay
13%13%5%7%6%36%445%28%
1644
16th to endDay
16%10%37%6%24446%32%
1580
March1st to 15thDay
15%11%46%5%25%45%7%30%
1790
16th to endDay
17%9%37%6%45%447%31%
2225
April1st to 15thDay
17%11%5%6%5%24445%31%
2151
16th to endDay
20%8%25%5%34446%34%
2217
May1st to 15thDay
18%9%36%5%35%5%5%7%29%
2365
16th to endDay
13%6%25%5%35%5%6%8%36%
2617
June1st to 15thDay
11%5%25%43446%7%43%
2520
16th to endDay
9%5%25%6%46%5%7%9%37%
2520
July1st to 15thDay
7%414436%7%6%9%44%
2520
16th to endDay
6%326%6%36%5%7%9%40%
2655
August1st to 15thDay
7%425%6%35%6%6%9%41%
2376
16th to endDay
9%4245%36%5%6%8%42%
2292
September1st to 15thDay
12%3133335%5%7%48%
2151
16th to endDay
9%5%25%5%245%6%7%44%
1881
October1st to 15thDay
14%5%35%43345%7%43%
1720
16th to endDay
17%8%35%43445%6%36%
1639
November1st to 15thDay
13%8%46%414446%41%
1582
16th to endDay
17%9%5%6%423345%35%
1567
December1st to 15thDay
17%12%49%6%25%235%29%
1440
16th to endDay
22%13%6%8%5%25%346%22%
1536
January1st to 15thNight
16%10%47%5%24345%34%
2506
16th to endNight
13%10%6%9%5%34447%29%
2646
February1st to 15thNight
14%13%5%6%423345%36%
2215
16th to endNight
15%10%36%5%34346%34%
1893
March1st to 15thNight
16%9%35%5%34345%37%
2147
16th to endNight
16%8%46%5%345%5%6%33%
2008
April1st to 15thNight
17%7%35%43445%5%36%
1797
16th to endNight
18%7%25%423346%39%
1743
May1st to 15thNight
18%5%245%35%6%5%7%35%
1584
16th to endNight
10%425%5%2346%8%44%
1496
June1st to 15thNight
10%425%43445%6%49%
1440
16th to endNight
7%425%6%35%6%7%9%41%
1440
July1st to 15thNight
5%314425%5%6%8%52%
1440
16th to endNight
5%3133346%7%9%51%
1513
August1st to 15thNight
33234345%6%9%53%
1583
16th to endNight
9%32432435%9%52%
1910
September1st to 15thNight
9%313323347%57%
1800
16th to endNight
8%5%145%3345%8%49%
1889
October1st to 15thNight
12%423324346%51%
1908
16th to endNight
19%7%25%423335%41%
2233
November1st to 15thNight
13%7%34423335%46%
2276
16th to endNight
17%9%36%42335%5%37%
2391
December1st to 15thNight
20%10%46%5%34346%31%
2520
16th to endNight
24%13%5%7%5%3443422%
2688

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%12%47%6%35%45%6%27%
1432
16th to endDay
13%13%7%10%5%33346%26%
1575
February1st to 15thDay
13%14%6%5%6%45%445%28%
1644
16th to endDay
15%11%46%6%2435%6%32%
1580
March1st to 15thDay
16%11%5%6%5%25%45%7%29%
1800
16th to endDay
18%9%36%5%44447%31%
2224
April1st to 15thDay
18%10%5%6%5%24445%31%
2151
16th to endDay
20%8%25%5%24446%35%
2217
May1st to 15thDay
19%9%36%5%35%5%5%7%28%
2365
16th to endDay
13%6%25%6%35%5%6%7%37%
2617
June1st to 15thDay
11%5%35%5%3445%7%43%
2520
16th to endDay
10%5%245%35%6%7%9%37%
2520
July1st to 15thDay
8%3145%26%6%6%9%44%
2520
16th to endDay
7%425%6%45%5%7%9%41%
2655
August1st to 15thDay
7%5%25%6%36%47%9%41%
2376
16th to endDay
10%4245%35%6%5%9%41%
2292
September1st to 15thDay
12%3134245%46%49%
2151
16th to endDay
9%5%25%4345%5%7%45%
1881
October1st to 15thDay
14%5%25%5%3335%7%43%
1720
16th to endDay
18%8%25%42445%6%36%
1639
November1st to 15thDay
13%8%35%42345%6%41%
1582
16th to endDay
17%10%45%423435%36%
1567
December1st to 15thDay
17%12%5%8%5%45%24429%
1440
16th to endDay
22%13%6%7%5%24346%23%
1536
January1st to 15thNight
16%11%46%5%24445%34%
2506
16th to endNight
13%11%7%9%5%2445%6%29%
2646
February1st to 15thNight
14%12%5%6%423346%36%
2208
16th to endNight
15%10%36%5%33247%35%
1893
March1st to 15thNight
16%10%45%5%34335%37%
2160
16th to endNight
16%8%37%5%35%45%7%33%
2008
April1st to 15thNight
17%8%35%5%3445%5%36%
1797
16th to endNight
19%7%25%423346%40%
1743
May1st to 15thNight
17%6%246%35%6%5%7%35%
1583
16th to endNight
11%425%42446%9%44%
1496
June1st to 15thNight
11%32443345%6%49%
1440
16th to endNight
8%415%5%35%5%8%8%42%
1440
July1st to 15thNight
6%313425%5%5%8%52%
1440
16th to endNight
5%2143345%7%9%51%
1513
August1st to 15thNight
4223435%5%7%9%53%
1583
16th to endNight
9%413323349%52%
1910
September1st to 15thNight
10%313333247%57%
1800
16th to endNight
8%4145%2345%8%49%
1889
October1st to 15thNight
12%423433446%50%
1908
16th to endNight
20%7%34423336%41%
2233
November1st to 15thNight
14%7%24323336%46%
2276
16th to endNight
17%9%46%423345%37%
2391
December1st to 15thNight
20%9%46%5%34346%31%
2520
16th to endNight
24%13%5%7%5%34435%22%
2688

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
56%5%13%14%9%
1433
16th to endDay
60%411%14%8%
1575
February1st to 15thDay
57%5%10%16%8%1
1646
16th to endDay
52%5%13%20%7%1
1580
March1st to 15thDay
53%6%13%19%7%
1800
16th to endDay
54%5%13%20%5%
2225
April1st to 15thDay
54%5%9%20%10%
2151
16th to endDay
49%6%12%18%11%2
2217
May1st to 15thDay
53%7%10%22%6%
2365
16th to endDay
43%6%12%20%14%1
2621
June1st to 15thDay
38%6%10%25%16%1
2520
16th to endDay
39%9%12%21%14%2
2520
July1st to 15thDay
33%8%13%26%14%2
2371
16th to endDay
35%7%16%22%13%3
2488
August1st to 15thDay
36%7%13%27%14%1
2361
16th to endDay
36%7%12%24%16%2
2292
September1st to 15thDay
34%6%10%24%20%4
2151
16th to endDay
35%6%9%29%17%1
1881
October1st to 15thDay
39%6%10%26%14%1
1720
16th to endDay
47%413%22%9%2
1639
November1st to 15thDay
43%5%10%24%14%2
1582
16th to endDay
50%413%23%6%
1567
December1st to 15thDay
58%413%16%7%
1440
16th to endDay
63%5%11%11%7%
1536
January1st to 15thNight
51%5%11%19%10%
2506
16th to endNight
55%413%16%9%
2646
February1st to 15thNight
50%411%20%11%
2217
16th to endNight
49%5%12%21%8%2
1893
March1st to 15thNight
50%5%12%18%10%2
2160
16th to endNight
49%6%12%20%9%1
2008
April1st to 15thNight
47%411%21%13%1
1797
16th to endNight
45%5%10%22%11%4
1743
May1st to 15thNight
46%6%11%23%10%
1584
16th to endNight
34%8%13%21%18%2
1498
June1st to 15thNight
34%5%11%25%19%3
1440
16th to endNight
36%8%12%21%18%2
1440
July1st to 15thNight
29%5%12%30%19%2
1360
16th to endNight
24%8%16%27%18%4
1417
August1st to 15thNight
25%6%14%31%19%1
1574
16th to endNight
28%6%14%27%18%4
1910
September1st to 15thNight
27%410%27%26%3
1800
16th to endNight
31%6%10%31%17%2
1889
October1st to 15thNight
33%5%10%27%21%1
1908
16th to endNight
45%310%25%13%1
2233
November1st to 15thNight
40%49%23%17%4
2276
16th to endNight
48%413%21%11%
2391
December1st to 15thNight
55%5%11%19%8%
2520
16th to endNight
66%39%13%5%
2688

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
22%13%38%22%3
90
16th to endDay
18%10%39%21%7%2
96
February1st to 15thDay
18%25%41%12%2
90
16th to endDay
24%9%38%16%8%2
81
March1st to 15thDay
38%17%22%16%31
90
16th to endDay
29%8%31%19%8%2
236
April1st to 15thDay
22%12%30%22%10%
270
16th to endDay
22%11%25%26%10%4
270
May1st to 15thDay
23%10%29%21%10%3
322
16th to endDay
18%9%30%23%13%4
517
June1st to 15thDay
12%5%30%30%16%4
495
16th to endDay
11%8%32%28%13%5%
495
July1st to 15thDay
8%426%32%17%10%
475
16th to endDay
6%226%33%19%10%
515
August1st to 15thDay
8%118%34%22%13%
412
16th to endDay
10%413%28%30%12%
332
September1st to 15thDay
9%417%33%25%9%
315
16th to endDay
9%6%19%28%27%8%
278
October1st to 15thDay
12%6%24%32%20%4
160
16th to endDay
27%16%30%22%3
96
November1st to 15thDay
10%12%26%33%11%6%
90
16th to endDay
35%12%32%13%6%
90
December1st to 15thDay
18%21%38%13%6%1
90
16th to endDay
28%22%43%32
96
January1st to 15thNight
21%12%39%21%5%
900
16th to endNight
18%11%36%29%3
960
February1st to 15thNight
21%12%35%24%5%
809
16th to endNight
20%11%34%26%6%
631
March1st to 15thNight
21%11%33%25%7%
720
16th to endNight
20%8%33%27%8%1
613
April1st to 15thNight
19%13%32%28%5%
539
16th to endNight
21%7%33%26%9%
540
May1st to 15thNight
21%5%30%31%10%
540
16th to endNight
11%6%28%36%17%
563
June1st to 15thNight
12%325%43%14%
540
16th to endNight
10%330%38%17%1
540
July1st to 15thNight
8%118%43%24%2
510
16th to endNight
5%116%46%27%3
564
August1st to 15thNight
418%50%30%4
539
16th to endNight
9%114%38%31%3
573
September1st to 15thNight
10%317%35%28%4
540
16th to endNight
9%5%20%34%27%3
682
October1st to 15thNight
13%7%25%32%18%2
660
16th to endNight
23%10%32%24%9%
704
November1st to 15thNight
17%10%35%25%10%1
700
16th to endNight
21%12%32%24%7%
771
December1st to 15thNight
26%12%32%23%5%
900
16th to endNight
30%11%32%22%3
960
Page generated at 2017-09-23 05:43:44. Version ac04

Copyright 2017 A. Danko


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