Persimmon Gap
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Persimmon Gap clear sky chart from 2005-11-05 to 2017-12-20.

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
70%
15739
32%
48188
27%
15699
76%
15699
47%
24314

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
65%
716
34%
2148
26%
716
72%
716
42%
1128
January16th to endNight
67%
768
37%
2304
31%
768
72%
768
45%
1204
February1st to 15thNight
64%
702
35%
2109
25%
699
73%
699
49%
1045
February16th to endNight
64%
632
34%
1894
24%
632
73%
632
53%
908
March1st to 15thNight
61%
720
33%
2160
22%
720
69%
720
46%
1116
March16th to endNight
58%
619
36%
1999
25%
619
70%
619
46%
969
April1st to 15thNight
55%
539
37%
1798
25%
539
72%
539
47%
836
April16th to endNight
55%
540
37%
1800
26%
540
72%
540
51%
807
May1st to 15thNight
55%
539
26%
1799
22%
539
66%
539
42%
894
May16th to endNight
64%
562
26%
1732
26%
561
70%
561
39%
944
June1st to 15thNight
77%
540
27%
1620
27%
540
81%
540
57%
756
June16th to endNight
79%
540
26%
1620
28%
540
80%
540
49%
807
July1st to 15thNight
82%
510
22%
1663
26%
510
83%
510
44%
838
July16th to endNight
83%
564
28%
1771
35%
531
86%
531
44%
885
August1st to 15thNight
86%
539
29%
1789
36%
536
88%
536
49%
845
August16th to endNight
80%
573
24%
1910
27%
573
81%
573
33%
1079
September1st to 15thNight
79%
540
22%
1842
23%
540
80%
540
34%
1021
September16th to endNight
72%
537
27%
1980
30%
537
73%
537
32%
1083
October1st to 15thNight
80%
540
35%
1980
36%
540
82%
540
46%
879
October16th to endNight
78%
720
41%
2256
33%
720
82%
720
56%
1021
November1st to 15thNight
76%
880
35%
2400
23%
880
79%
880
59%
1164
November16th to endNight
73%
975
39%
2535
24%
975
78%
975
59%
1289
December1st to 15thNight
70%
975
36%
2535
25%
975
72%
975
48%
1418
December16th to endNight
65%
969
37%
2544
23%
969
71%
969
50%
1378

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
4312323447%61%
48613
Night
431232345%7%61%
48411
Cloud CoverDay
5%312323347%62%
48611
Night
5%21232335%7%61%
48411
TransparencyDay
21%49%19%24%20%
48333
Night
21%49%19%23%21%
48193
SeeingDay
5%5%19%32%27%9%
5489
Night
5%216%45%28%1
15747

By Month

Percentage Cloud Cover SW (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
8%413323246%58%
1790
16th to endDay
5%312323236%65%
1920
February1st to 15thDay
2212223336%69%
1750
16th to endDay
3212113337%69%
1580
March1st to 15thDay
3413324446%62%
1800
16th to endDay
4312313336%66%
2220
April1st to 15thDay
2212213347%67%
2150
16th to endDay
2212213336%69%
2160
May1st to 15thDay
321221335%7%65%
2151
16th to endDay
422213347%65%
2379
June1st to 15thDay
111213349%69%
2340
16th to endDay
321232445%10%58%
2340
July1st to 15thDay
5%223425%5%6%9%51%
2192
16th to endDay
5%313335%5%8%11%49%
2277
August1st to 15thDay
32122236%7%11%54%
2160
16th to endDay
5%213425%7%7%10%46%
2292
September1st to 15thDay
7%5%15%5%35%5%6%9%45%
2117
16th to endDay
8%3135%345%47%51%
1980
October1st to 15thDay
4312223347%64%
1980
16th to endDay
5%11121223471%
1965
November1st to 15thDay
6%2221212472%
1772
16th to endDay
421221223372%
1755
December1st to 15thDay
6%5%1231333462%
1755
16th to endDay
4412324446%62%
1788
January1st to 15thNight
6%424323335%60%
2148
16th to endNight
7%41232335%7%59%
2304
February1st to 15thNight
3312313346%65%
2102
16th to endNight
332213446%66%
1894
March1st to 15thNight
4412323346%61%
2160
16th to endNight
4412223345%65%
1999
April1st to 15thNight
321231335%5%66%
1798
16th to endNight
2212322246%68%
1800
May1st to 15thNight
431232345%6%61%
1799
16th to endNight
5%213336%47%8%55%
1731
June1st to 15thNight
111222246%12%61%
1620
16th to endNight
211222448%11%57%
1620
July1st to 15thNight
42123245%7%12%54%
1763
16th to endNight
321333346%11%55%
1891
August1st to 15thNight
21332345%14%56%
1800
16th to endNight
4213446%6%8%12%45%
1910
September1st to 15thNight
5%3144345%7%11%49%
1842
16th to endNight
9%3134245%6%10%47%
1980
October1st to 15thNight
42221346%6%64%
1980
16th to endNight
421221222473%
2256
November1st to 15thNight
5%311212235%71%
2400
16th to endNight
41221233472%
2535
December1st to 15thNight
5%42232335%7%59%
2535
16th to endNight
3413323345%63%
2544

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
8%423312345%59%
1790
16th to endDay
6%312313345%65%
1920
February1st to 15thDay
222313335%70%
1750
16th to endDay
3212122337%69%
1580
March1st to 15thDay
341222335%6%62%
1800
16th to endDay
4312223336%66%
2218
April1st to 15thDay
2212223246%67%
2150
16th to endDay
3211213336%69%
2160
May1st to 15thDay
3112213347%66%
2151
16th to endDay
5%22213347%65%
2379
June1st to 15thDay
111213348%70%
2340
16th to endDay
421232445%9%59%
2340
July1st to 15thDay
5%313435%5%7%8%52%
2192
16th to endDay
5%213335%6%6%10%50%
2277
August1st to 15thDay
4222245%7%10%56%
2160
16th to endDay
6%213435%6%8%10%47%
2292
September1st to 15thDay
8%5%245%35%46%8%46%
2117
16th to endDay
8%3135%3445%7%51%
1980
October1st to 15thDay
5%312213347%64%
1980
16th to endDay
5%21122323372%
1965
November1st to 15thDay
6%2221212472%
1772
16th to endDay
431221222372%
1755
December1st to 15thDay
7%5%231333463%
1755
16th to endDay
4412214447%62%
1788
January1st to 15thNight
6%423423345%60%
2148
16th to endNight
7%313323246%60%
2304
February1st to 15thNight
4312313346%65%
2102
16th to endNight
422212446%67%
1894
March1st to 15thNight
4412323347%62%
2160
16th to endNight
4412313335%66%
1999
April1st to 15thNight
4212313446%65%
1798
16th to endNight
321222225%5%69%
1800
May1st to 15thNight
5%31232445%6%61%
1799
16th to endNight
6%113335%36%8%55%
1731
June1st to 15thNight
11131336%12%62%
1620
16th to endNight
32122245%7%11%58%
1620
July1st to 15thNight
42122245%8%11%54%
1763
16th to endNight
32123245%6%11%55%
1891
August1st to 15thNight
311232346%14%56%
1800
16th to endNight
42135%35%7%7%12%45%
1910
September1st to 15thNight
5%2234245%7%10%49%
1842
16th to endNight
9%313325%45%10%48%
1980
October1st to 15thNight
5%21222335%7%64%
1980
16th to endNight
5%11221222473%
2256
November1st to 15thNight
6%2112245%71%
2400
16th to endNight
5%11221223473%
2535
December1st to 15thNight
6%312323347%60%
2535
16th to endNight
4313323345%63%
2544

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
28%35%18%30%13%
1791
16th to endDay
22%35%16%32%19%
1920
February1st to 15thDay
17%36%15%25%31%
1751
16th to endDay
16%15%13%33%28%
1580
March1st to 15thDay
23%36%15%21%29%
1800
16th to endDay
21%35%11%25%33%
2220
April1st to 15thDay
16%47%11%23%36%
2150
16th to endDay
16%25%11%22%40%
2160
May1st to 15thDay
17%5%6%14%24%31%
2151
16th to endDay
18%48%18%24%25%
2382
June1st to 15thDay
12%49%21%30%21%
2340
16th to endDay
21%6%13%20%24%12%
2340
July1st to 15thDay
25%7%13%26%20%5%
2063
16th to endDay
23%8%16%30%17%3
2134
August1st to 15thDay
19%7%15%30%22%4
2147
16th to endDay
27%10%16%25%14%6%
2292
September1st to 15thDay
34%7%14%21%16%6%
2117
16th to endDay
30%6%11%18%22%10%
1980
October1st to 15thDay
19%5%11%25%20%17%
1980
16th to endDay
17%3415%27%32%
1965
November1st to 15thDay
17%25%24%29%20%
1772
16th to endDay
17%25%15%30%27%
1755
December1st to 15thDay
25%25%20%30%14%
1755
16th to endDay
21%35%23%32%13%
1788
January1st to 15thNight
26%35%16%29%18%
2148
16th to endNight
24%25%15%29%21%
2304
February1st to 15thNight
20%35%11%24%34%
2112
16th to endNight
18%36%11%28%31%
1894
March1st to 15thNight
24%36%14%21%29%
2160
16th to endNight
21%36%15%22%31%
1999
April1st to 15thNight
19%46%14%19%36%
1798
16th to endNight
17%36%14%21%36%
1800
May1st to 15thNight
22%5%8%16%19%28%
1800
16th to endNight
25%6%9%19%17%20%
1733
June1st to 15thNight
13%5%12%25%28%13%
1620
16th to endNight
19%5%14%21%25%12%
1620
July1st to 15thNight
21%6%16%32%19%4
1663
16th to endNight
20%7%14%34%20%2
1771
August1st to 15thNight
18%5%16%28%27%3
1789
16th to endNight
26%10%15%26%15%5%
1910
September1st to 15thNight
26%9%19%23%13%7%
1842
16th to endNight
30%6%15%21%17%9%
1980
October1st to 15thNight
17%5%13%27%18%17%
1980
16th to endNight
17%2416%27%32%
2256
November1st to 15thNight
17%27%18%33%21%
2400
16th to endNight
16%36%12%26%34%
2535
December1st to 15thNight
25%36%19%25%20%
2535
16th to endNight
22%3419%29%19%
2544

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
12%325%37%20%1
90
16th to endDay
413%22%37%18%3
96
February1st to 15thDay
36%12%32%34%11%
90
16th to endDay
11%7%19%37%16%8%
81
March1st to 15thDay
8%425%26%31%3
90
16th to endDay
317%32%27%15%4
249
April1st to 15thDay
318%39%27%10%1
269
16th to endDay
216%42%27%7%2
270
May1st to 15thDay
213%42%34%6%
288
16th to endDay
7%427%35%22%2
466
June1st to 15thDay
1116%33%41%5%
495
16th to endDay
3113%29%42%10%
495
July1st to 15thDay
410%32%37%14%
337
16th to endDay
214%39%27%17%
327
August1st to 15thDay
37%40%26%21%
315
16th to endDay
7%8%43%26%14%
332
September1st to 15thDay
6%9%39%29%14%
272
16th to endDay
17%5%17%41%17%
135
October1st to 15thDay
9%29%20%40%17%
135
16th to endDay
2116%24%36%18%
144
November1st to 15thDay
11%413%28%28%14%
135
16th to endDay
7%7%17%25%31%11%
135
December1st to 15thDay
13%5%15%26%28%10%
135
16th to endDay
5%6%25%39%22%
108
January1st to 15thNight
8%116%50%20%1
720
16th to endNight
9%314%52%19%
768
February1st to 15thNight
5%420%48%20%
704
16th to endNight
3325%56%10%
632
March1st to 15thNight
8%222%50%15%
720
16th to endNight
5%427%45%15%
619
April1st to 15thNight
4432%50%8%
539
16th to endNight
2434%47%10%
540
May1st to 15thNight
6%429%50%10%
540
16th to endNight
5%124%48%20%
563
June1st to 15thNight
1116%50%30%
540
16th to endNight
2110%41%44%
540
July1st to 15thNight
5%6%36%49%1
510
16th to endNight
45%33%53%3
564
August1st to 15thNight
2425%63%4
539
16th to endNight
36%31%54%2
573
September1st to 15thNight
5%6%33%52%2
540
16th to endNight
11%8%38%38%2
537
October1st to 15thNight
5%9%45%36%2
540
16th to endNight
5%19%46%31%5%
720
November1st to 15thNight
7%19%45%30%4
880
16th to endNight
5%213%45%29%3
975
December1st to 15thNight
8%212%50%23%1
975
16th to endNight
5%319%53%16%1
969
Page generated at 2017-12-21 06:04:52. Version ac04

Copyright 2017 A. Danko


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