Duette Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Duette Park clear sky chart from 2005-11-05 to 2017-09-24.

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
63%
15965
20%
47041
17%
15926
67%
15926
30%
29499

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
51%
717
19%
2327
15%
716
57%
716
26%
1440
January16th to endNight
49%
768
24%
2403
20%
768
57%
768
29%
1444
February1st to 15thNight
50%
701
24%
2105
18%
699
57%
699
31%
1276
February16th to endNight
52%
631
26%
1839
18%
631
61%
631
39%
1044
March1st to 15thNight
56%
720
30%
1980
19%
720
65%
720
43%
1101
March16th to endNight
58%
768
26%
2112
21%
768
62%
768
40%
1223
April1st to 15thNight
64%
718
23%
1976
19%
718
68%
718
45%
1104
April16th to endNight
63%
720
27%
1872
19%
720
67%
720
42%
1091
May1st to 15thNight
77%
568
28%
1648
23%
568
79%
568
45%
899
May16th to endNight
78%
561
23%
1683
19%
561
80%
561
37%
1006
June1st to 15thNight
72%
540
10%
1620
9%
540
72%
540
24%
1133
June16th to endNight
78%
540
7%
1620
6%
540
78%
540
21%
1164
July1st to 15thNight
74%
510
5%
1530
6%
510
74%
510
19%
1151
July16th to endNight
78%
564
7%
1595
7%
531
78%
531
21%
1176
August1st to 15thNight
79%
539
5%
1657
6%
536
79%
536
25%
1144
August16th to endNight
66%
715
7%
2052
6%
715
66%
715
19%
1495
September1st to 15thNight
65%
720
7%
1980
7%
720
66%
720
18%
1494
September16th to endNight
62%
693
11%
1914
11%
693
63%
693
20%
1397
October1st to 15thNight
70%
660
25%
1856
25%
660
71%
660
33%
1158
October16th to endNight
60%
704
26%
2112
24%
704
65%
704
31%
1277
November1st to 15thNight
65%
700
31%
2101
28%
700
72%
700
40%
1167
November16th to endNight
57%
720
30%
2223
25%
720
64%
720
34%
1288
December1st to 15thNight
57%
720
25%
2340
23%
720
62%
720
30%
1390
December16th to endNight
60%
768
24%
2496
24%
768
64%
768
32%
1437

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%36%7%46%6%6%8%36%
47869
Night
7%425%5%35%5%6%9%43%
47247
TransparencyDay
43%8%13%16%13%5%
47570
Night
34%8%16%19%14%5%
47050
SeeingDay
9%210%20%26%31%
5817
Night
8%214%33%29%10%
15974

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
10%5%36%5%346%5%9%37%
1611
16th to endDay
9%5%245%245%5%8%46%
1818
February1st to 15thDay
11%6%25%42446%5%45%
1750
16th to endDay
7%425%5%3445%8%48%
1631
March1st to 15thDay
5%2145%35%447%53%
1980
16th to endDay
8%4235%3445%7%49%
2111
April1st to 15thDay
6%3245%46%6%6%9%43%
1972
16th to endDay
6%4246%345%5%8%47%
2085
May1st to 15thDay
5%3245%36%5%5%8%50%
2311
16th to endDay
7%5%36%7%5%7%6%7%8%35%
2431
June1st to 15thDay
12%9%38%9%48%6%5%8%22%
2340
16th to endDay
8%6%47%9%6%8%9%8%9%21%
2340
July1st to 15thDay
10%6%39%10%6%7%9%8%7%20%
2340
16th to endDay
10%7%48%10%6%8%7%6%9%19%
2465
August1st to 15thDay
7%6%39%9%7%9%9%7%9%21%
2288
16th to endDay
11%7%38%9%6%7%7%7%8%21%
2136
September1st to 15thDay
8%7%39%11%6%7%7%7%10%20%
1980
16th to endDay
9%7%410%10%5%7%6%6%8%22%
1905
October1st to 15thDay
8%5%27%6%37%5%6%7%39%
1774
16th to endDay
9%5%35%4445%47%45%
1760
November1st to 15thDay
5%4245%35%46%7%49%
1757
16th to endDay
7%5%25%5%35%5%46%48%
1736
December1st to 15thDay
8%5%35%5%35%5%6%7%40%
1620
16th to endDay
7%5%25%5%3447%8%45%
1728
January1st to 15thNight
9%7%36%5%345%5%9%40%
2327
16th to endNight
10%5%244345%6%8%43%
2403
February1st to 15thNight
9%5%245%34437%47%
2103
16th to endNight
6%4144235%6%9%50%
1839
March1st to 15thNight
421432445%8%56%
1980
16th to endNight
5%325%423447%54%
2112
April1st to 15thNight
421342445%10%55%
1976
16th to endNight
5%32443445%8%52%
1872
May1st to 15thNight
331432445%7%59%
1648
16th to endNight
5%414435%5%5%10%48%
1682
June1st to 15thNight
9%6%26%6%36%7%7%10%33%
1620
16th to endNight
5%325%7%38%7%9%14%31%
1620
July1st to 15thNight
6%5%27%8%45%7%9%12%29%
1620
16th to endNight
4435%7%49%8%9%14%27%
1703
August1st to 15thNight
4425%7%46%6%8%12%36%
1668
16th to endNight
8%5%26%7%46%6%8%12%29%
2052
September1st to 15thNight
7%6%36%7%47%7%7%12%29%
1980
16th to endNight
9%6%28%7%47%7%7%8%29%
1914
October1st to 15thNight
6%435%5%3446%8%47%
1856
16th to endNight
9%5%25%325%45%6%48%
2112
November1st to 15thNight
5%32442445%8%52%
2101
16th to endNight
7%425%5%24448%49%
2223
December1st to 15thNight
8%5%25%5%35%5%6%7%44%
2340
16th to endNight
6%4235%26%6%6%9%46%
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
40%6%8%21%18%5%
1612
16th to endDay
35%5%7%20%23%7%
1818
February1st to 15thDay
37%5%6%16%20%14%
1752
16th to endDay
34%49%17%22%11%
1631
March1st to 15thDay
29%410%24%21%9%
1980
16th to endDay
32%49%22%21%8%
2112
April1st to 15thDay
34%6%12%20%19%6%
1972
16th to endDay
33%5%10%19%23%7%
2085
May1st to 15thDay
29%7%13%21%19%8%
2311
16th to endDay
43%8%13%18%14%1
2435
June1st to 15thDay
57%9%15%14%3
2340
16th to endDay
54%11%19%12%1
2340
July1st to 15thDay
58%13%19%6%1
2201
16th to endDay
54%13%21%8%1
2310
August1st to 15thDay
53%13%24%8%
2275
16th to endDay
56%14%18%9%
2136
September1st to 15thDay
55%12%19%10%2
1980
16th to endDay
55%9%17%11%41
1905
October1st to 15thDay
41%7%10%16%16%7%
1774
16th to endDay
37%5%8%14%21%12%
1760
November1st to 15thDay
31%38%23%22%9%
1757
16th to endDay
35%5%9%19%17%13%
1736
December1st to 15thDay
40%5%12%18%16%6%
1620
16th to endDay
34%413%21%18%7%
1728
January1st to 15thNight
39%5%11%23%15%5%
2327
16th to endNight
36%49%21%19%7%
2403
February1st to 15thNight
36%47%17%22%12%
2112
16th to endNight
29%415%20%21%8%
1839
March1st to 15thNight
25%5%12%28%21%7%
1980
16th to endNight
28%5%12%24%21%8%
2112
April1st to 15thNight
24%6%17%25%20%6%
1976
16th to endNight
27%5%12%24%23%6%
1872
May1st to 15thNight
22%7%13%29%19%6%
1649
16th to endNight
30%7%19%24%16%1
1684
June1st to 15thNight
42%10%24%17%5%
1620
16th to endNight
39%16%25%13%4
1620
July1st to 15thNight
43%16%29%7%1
1530
16th to endNight
40%17%28%13%
1595
August1st to 15thNight
35%16%37%10%
1657
16th to endNight
43%15%28%10%1
2052
September1st to 15thNight
44%16%22%13%2
1980
16th to endNight
47%10%20%14%41
1914
October1st to 15thNight
32%8%13%18%19%7%
1856
16th to endNight
35%5%9%16%22%9%
2112
November1st to 15thNight
28%410%23%22%10%
2101
16th to endNight
33%49%22%17%12%
2223
December1st to 15thNight
36%413%23%16%5%
2340
16th to endNight
32%5%15%20%18%7%
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
20%10%25%24%14%5%
90
16th to endDay
14%12%31%28%9%4
96
February1st to 15thDay
10%7%24%31%17%8%
90
16th to endDay
11%332%35%16%
132
March1st to 15thDay
5%325%37%24%3
270
16th to endDay
9%418%30%28%7%
288
April1st to 15thDay
7%120%30%31%8%
270
16th to endDay
6%310%28%34%17%
270
May1st to 15thDay
5%28%22%36%23%
288
16th to endDay
7%1317%31%37%
331
June1st to 15thDay
19%2311%21%41%
315
16th to endDay
7%26%23%60%
315
July1st to 15thDay
7%1413%73%
305
16th to endDay
13%37%17%58%
326
August1st to 15thDay
9%25%18%64%
313
16th to endDay
11%136%24%53%
332
September1st to 15thDay
11%348%24%47%
315
16th to endDay
7%1112%37%40%
287
October1st to 15thDay
7%15%27%39%18%
255
16th to endDay
11%214%31%26%13%
272
November1st to 15thDay
9%112%32%32%12%
265
16th to endDay
7%220%33%28%6%
206
December1st to 15thDay
11%228%42%15%
90
16th to endDay
4412%32%41%5%
96
January1st to 15thNight
11%5%20%41%19%
720
16th to endNight
12%5%25%40%14%1
768
February1st to 15thNight
11%6%26%42%12%
704
16th to endNight
8%328%45%13%
631
March1st to 15thNight
5%428%45%14%
720
16th to endNight
6%423%45%19%1
768
April1st to 15thNight
5%321%46%23%
718
16th to endNight
7%220%44%25%
720
May1st to 15thNight
419%50%31%3
569
16th to endNight
5%15%35%42%9%
563
June1st to 15thNight
10%321%46%16%
540
16th to endNight
5%212%43%36%
540
July1st to 15thNight
7%16%46%37%
510
16th to endNight
5%26%45%40%
564
August1st to 15thNight
5%16%43%42%
539
16th to endNight
10%1412%38%31%
715
September1st to 15thNight
9%1417%42%24%
720
16th to endNight
12%1323%43%15%
693
October1st to 15thNight
9%16%40%36%5%
660
16th to endNight
12%116%34%33%2
704
November1st to 15thNight
7%216%45%24%3
700
16th to endNight
8%222%42%22%1
720
December1st to 15thNight
9%321%40%25%
720
16th to endNight
7%321%41%25%1
768
Page generated at 2017-09-25 09:02:27. Version ac04

Copyright 2017 A. Danko


Duette Park Clear Sky Chart | Charts Home