Jigg's Landing Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jigg's Landing Park clear sky chart from 2005-11-05 to 2017-09-19.

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
64%
15900
20%
46993
17%
15861
68%
15861
31%
29157

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
53%
717
18%
2327
15%
716
59%
716
25%
1458
January16th to endNight
51%
768
25%
2377
20%
768
57%
768
30%
1424
February1st to 15thNight
50%
701
25%
2104
19%
699
57%
699
33%
1259
February16th to endNight
56%
631
24%
1857
17%
631
63%
631
37%
1059
March1st to 15thNight
55%
720
30%
1980
18%
720
65%
720
45%
1082
March16th to endNight
61%
768
27%
2112
21%
768
65%
768
40%
1198
April1st to 15thNight
65%
718
22%
1976
18%
718
68%
718
45%
1093
April16th to endNight
63%
720
27%
1893
20%
720
67%
720
43%
1108
May1st to 15thNight
80%
539
29%
1619
25%
539
82%
539
46%
851
May16th to endNight
76%
561
24%
1683
21%
561
77%
561
38%
984
June1st to 15thNight
73%
540
11%
1620
10%
540
73%
540
25%
1105
June16th to endNight
80%
540
9%
1620
8%
540
81%
540
26%
1092
July1st to 15thNight
77%
510
6%
1530
6%
510
77%
510
20%
1127
July16th to endNight
79%
564
8%
1595
9%
531
80%
531
23%
1117
August1st to 15thNight
81%
539
4%
1696
5%
536
82%
536
25%
1148
August16th to endNight
69%
699
8%
2036
8%
699
69%
699
19%
1502
September1st to 15thNight
67%
720
7%
1980
8%
720
67%
720
19%
1464
September16th to endNight
62%
673
10%
1858
9%
673
63%
673
20%
1362
October1st to 15thNight
73%
660
24%
1840
24%
660
74%
660
35%
1117
October16th to endNight
59%
704
25%
2112
24%
704
63%
704
33%
1268
November1st to 15thNight
63%
700
30%
2101
27%
700
69%
700
38%
1191
November16th to endNight
55%
720
28%
2241
24%
720
62%
720
34%
1295
December1st to 15thNight
57%
720
24%
2340
24%
720
61%
720
28%
1423
December16th to endNight
60%
768
24%
2496
25%
768
63%
768
32%
1430

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
8%5%25%6%46%6%7%9%38%
47805
Night
7%425%5%35%5%6%9%44%
47200
TransparencyDay
39%9%15%17%13%4
47506
Night
33%8%17%20%14%5%
47003
SeeingDay
9%211%21%27%27%
5758
Night
8%214%33%30%11%
15909

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
11%5%26%5%345%5%10%38%
1611
16th to endDay
10%4245%2445%8%47%
1845
February1st to 15thDay
10%6%2442445%6%48%
1750
16th to endDay
7%42342345%7%53%
1613
March1st to 15thDay
422342345%7%57%
1980
16th to endDay
8%42433445%8%50%
2111
April1st to 15thDay
6%325%435%5%7%9%47%
1972
16th to endDay
6%3144345%6%8%51%
2073
May1st to 15thDay
43133245%7%9%54%
2331
16th to endDay
7%425%6%47%6%7%8%39%
2431
June1st to 15thDay
11%8%26%7%47%7%7%10%25%
2340
16th to endDay
8%6%25%8%5%10%9%9%10%24%
2340
July1st to 15thDay
9%447%8%6%9%9%9%10%21%
2340
16th to endDay
7%5%38%8%7%10%8%10%11%19%
2465
August1st to 15thDay
6%5%38%8%5%10%10%11%10%20%
2250
16th to endDay
10%5%37%8%6%8%9%9%10%21%
2154
September1st to 15thDay
9%5%38%8%5%8%9%8%10%21%
1980
16th to endDay
9%6%28%10%5%7%7%8%10%22%
1848
October1st to 15thDay
6%425%7%46%5%7%8%40%
1790
16th to endDay
10%5%245%3445%8%46%
1760
November1st to 15thDay
5%4145%35%5%6%7%49%
1757
16th to endDay
8%3235%3446%8%48%
1716
December1st to 15thDay
9%5%35%5%35%5%6%8%41%
1620
16th to endDay
7%5%245%3445%8%47%
1728
January1st to 15thNight
8%6%35%5%46%5%5%9%39%
2327
16th to endNight
11%5%244235%6%8%43%
2377
February1st to 15thNight
11%5%25%423336%49%
2103
16th to endNight
6%5%14425%5%6%7%49%
1857
March1st to 15thNight
42134245%6%9%55%
1980
16th to endNight
6%325%423448%54%
2112
April1st to 15thNight
42134235%6%8%55%
1976
16th to endNight
5%31342446%8%53%
1893
May1st to 15thNight
321232445%8%59%
1619
16th to endNight
44245%25%5%6%8%51%
1682
June1st to 15thNight
10%5%25%5%36%6%7%10%35%
1620
16th to endNight
5%4245%36%7%9%13%36%
1620
July1st to 15thNight
6%5%25%5%47%7%9%12%32%
1620
16th to endNight
3425%5%5%8%8%10%13%31%
1703
August1st to 15thNight
5%325%5%46%6%9%15%35%
1707
16th to endNight
8%425%7%47%7%8%12%30%
2036
September1st to 15thNight
6%5%36%8%5%8%6%8%11%28%
1980
16th to endNight
9%6%37%7%47%7%7%11%27%
1858
October1st to 15thNight
5%4145%345%5%10%47%
1840
16th to endNight
8%5%25%43445%9%46%
2112
November1st to 15thNight
5%3344245%5%8%51%
2101
16th to endNight
7%4245%245%49%48%
2241
December1st to 15thNight
9%5%24435%5%5%7%44%
2340
16th to endNight
7%4245%35%46%8%47%
2496

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
39%6%11%22%16%4
1612
16th to endDay
34%5%8%20%22%7%
1845
February1st to 15thDay
35%5%8%18%19%12%
1752
16th to endDay
30%5%13%18%23%10%
1613
March1st to 15thDay
24%5%11%27%22%8%
1980
16th to endDay
30%5%10%23%21%7%
2112
April1st to 15thDay
31%7%14%20%20%5%
1972
16th to endDay
30%6%12%19%25%5%
2073
May1st to 15thDay
25%8%14%25%20%7%
2331
16th to endDay
38%9%13%21%14%1
2435
June1st to 15thDay
49%12%17%17%3
2340
16th to endDay
48%14%22%12%2
2340
July1st to 15thDay
53%17%20%5%2
2201
16th to endDay
49%14%23%10%
2310
August1st to 15thDay
47%18%26%7%
2237
16th to endDay
51%17%20%9%
2154
September1st to 15thDay
52%14%20%10%1
1980
16th to endDay
51%13%15%13%41
1848
October1st to 15thDay
38%8%10%16%17%7%
1790
16th to endDay
37%5%8%17%20%11%
1760
November1st to 15thDay
31%410%21%23%8%
1757
16th to endDay
33%6%9%20%17%12%
1716
December1st to 15thDay
39%5%12%20%16%5%
1620
16th to endDay
33%6%12%21%19%6%
1728
January1st to 15thNight
39%5%12%23%13%3
2327
16th to endNight
36%410%21%19%7%
2377
February1st to 15thNight
35%37%19%21%12%
2112
16th to endNight
29%5%15%20%21%7%
1857
March1st to 15thNight
24%5%13%29%20%6%
1980
16th to endNight
28%413%24%21%7%
2112
April1st to 15thNight
24%5%19%25%19%5%
1976
16th to endNight
26%6%13%23%25%4
1893
May1st to 15thNight
22%6%13%30%20%6%
1620
16th to endNight
28%7%17%28%17%1
1684
June1st to 15thNight
41%9%23%19%5%
1620
16th to endNight
33%15%28%17%5%
1620
July1st to 15thNight
41%17%31%8%1
1530
16th to endNight
36%16%31%14%
1595
August1st to 15thNight
33%17%38%10%
1696
16th to endNight
42%16%27%12%1
2036
September1st to 15thNight
45%14%24%13%2
1980
16th to endNight
45%12%21%14%41
1858
October1st to 15thNight
30%8%15%17%19%7%
1840
16th to endNight
34%5%11%14%23%9%
2112
November1st to 15thNight
30%49%22%22%9%
2101
16th to endNight
31%6%11%22%16%12%
2241
December1st to 15thNight
37%5%12%23%16%4
2340
16th to endNight
32%5%14%21%18%6%
2496

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%6%27%25%14%3
90
16th to endDay
10%15%33%29%9%2
96
February1st to 15thDay
13%14%23%28%15%4
90
16th to endDay
10%331%39%14%
114
March1st to 15thDay
5%330%36%22%2
270
16th to endDay
10%5%20%32%24%5%
288
April1st to 15thDay
5%222%34%28%5%
270
16th to endDay
7%11%35%32%11%
270
May1st to 15thDay
7%110%27%34%18%
288
16th to endDay
5%25%20%31%34%
331
June1st to 15thDay
17%26%12%24%37%
315
16th to endDay
6%37%24%55%
315
July1st to 15thDay
6%1124%65%
305
16th to endDay
12%127%21%54%
326
August1st to 15thDay
8%26%23%58%
313
16th to endDay
10%38%27%49%
332
September1st to 15thDay
12%249%30%40%
315
16th to endDay
8%1213%40%33%
266
October1st to 15thDay
7%6%30%40%15%
255
16th to endDay
13%213%30%28%11%
272
November1st to 15thDay
6%112%32%36%10%
265
16th to endDay
7%223%36%24%6%
186
December1st to 15thDay
11%332%37%14%1
90
16th to endDay
8%414%29%36%7%
96
January1st to 15thNight
11%422%41%19%1
720
16th to endNight
11%6%23%42%15%
768
February1st to 15thNight
12%5%24%42%13%1
704
16th to endNight
8%424%45%17%
631
March1st to 15thNight
5%330%42%15%1
720
16th to endNight
6%320%47%19%2
768
April1st to 15thNight
5%220%44%25%1
718
16th to endNight
7%221%44%23%1
720
May1st to 15thNight
5%17%46%36%3
540
16th to endNight
6%6%33%44%8%
563
June1st to 15thNight
9%1219%49%18%
540
16th to endNight
5%110%45%35%
540
July1st to 15thNight
8%343%42%
510
16th to endNight
416%44%42%
564
August1st to 15thNight
6%5%42%45%
539
16th to endNight
11%1311%40%32%
699
September1st to 15thNight
7%2316%45%24%
720
16th to endNight
12%1221%45%16%
673
October1st to 15thNight
7%16%40%37%6%
660
16th to endNight
12%117%33%30%4
704
November1st to 15thNight
6%119%44%24%2
700
16th to endNight
7%324%41%20%2
720
December1st to 15thNight
10%419%40%23%1
720
16th to endNight
7%320%42%24%1
768
Page generated at 2017-09-20 04:49:45. Version ac04

Copyright 2017 A. Danko


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