Whitewater Preserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Whitewater Preserve 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
65%
16172
36%
47025
27%
16132
73%
16132
62%
20945

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
59%
717
30%
2327
26%
716
68%
716
48%
1078
January16th to endNight
55%
768
34%
2342
26%
768
67%
768
47%
1159
February1st to 15thNight
57%
697
33%
2108
26%
697
68%
697
51%
1015
February16th to endNight
50%
632
32%
1895
27%
632
61%
632
44%
971
March1st to 15thNight
55%
720
32%
2151
25%
720
68%
720
54%
995
March16th to endNight
55%
768
33%
2055
22%
768
65%
768
55%
1015
April1st to 15thNight
43%
719
33%
1799
13%
719
56%
719
55%
919
April16th to endNight
50%
720
37%
1800
15%
720
60%
720
67%
853
May1st to 15thNight
55%
547
38%
1627
22%
547
64%
547
71%
635
May16th to endNight
51%
562
37%
1685
21%
561
62%
561
72%
651
June1st to 15thNight
57%
540
35%
1620
23%
540
65%
540
75%
627
June16th to endNight
72%
540
37%
1620
30%
540
76%
540
86%
596
July1st to 15thNight
81%
510
31%
1530
26%
510
84%
510
73%
611
July16th to endNight
83%
576
34%
1604
28%
542
84%
542
61%
725
August1st to 15thNight
86%
717
38%
1790
24%
713
88%
713
82%
798
August16th to endNight
88%
764
43%
1910
29%
764
89%
764
80%
865
September1st to 15thNight
86%
720
40%
1880
29%
720
90%
720
77%
822
September16th to endNight
81%
683
49%
1890
39%
683
89%
683
86%
738
October1st to 15thNight
67%
660
41%
1815
29%
660
78%
660
70%
798
October16th to endNight
75%
704
41%
2126
37%
704
83%
704
69%
867
November1st to 15thNight
71%
700
37%
2275
33%
700
82%
700
67%
892
November16th to endNight
67%
720
39%
2340
36%
720
77%
720
60%
975
December1st to 15thNight
59%
720
33%
2340
27%
720
69%
720
47%
1101
December16th to endNight
52%
768
33%
2496
26%
768
63%
768
42%
1239

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
111212336%74%
47853
Night
111212236%76%
47226
TransparencyDay
10%5%8%12%26%36%
47550
Night
9%5%9%13%26%34%
47030
SeeingDay
213%34%34%12%2
5873
Night
15%25%36%26%4
16184

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
212222447%67%
1611
16th to endDay
421231345%7%62%
1881
February1st to 15thDay
2112213347%67%
1751
16th to endDay
211442445%8%61%
1579
March1st to 15thDay
111112348%71%
1809
16th to endDay
1131345%8%68%
2166
April1st to 15thDay
113224437%68%
2149
16th to endDay
1111235%80%
2160
May1st to 15thDay
1112125%82%
2322
16th to endDay
11122483%
2429
June1st to 15thDay
112485%
2340
16th to endDay
1111288%
2340
July1st to 15thDay
212212245%73%
2340
16th to endDay
11222445%6%67%
2452
August1st to 15thDay
1111333477%
2160
16th to endDay
11111123478%
2292
September1st to 15thDay
11121233476%
2079
16th to endDay
1112385%
1882
October1st to 15thDay
2212235%78%
1815
16th to endDay
11112236%79%
1744
November1st to 15thDay
111212235%77%
1584
16th to endDay
112213345%71%
1620
December1st to 15thDay
323323448%64%
1620
16th to endDay
311223345%8%63%
1728
January1st to 15thNight
11231345%7%66%
2327
16th to endNight
4112323347%65%
2342
February1st to 15thNight
122313347%69%
2101
16th to endNight
31232345%10%63%
1895
March1st to 15thNight
111213447%70%
2151
16th to endNight
1121235%9%71%
2055
April1st to 15thNight
111212327%75%
1799
16th to endNight
111125%83%
1800
May1st to 15thNight
1125%85%
1627
16th to endNight
1225%85%
1684
June1st to 15thNight
11111486%
1620
16th to endNight
11191%
1620
July1st to 15thNight
1111223478%
1620
16th to endNight
11212347%72%
1713
August1st to 15thNight
11223482%
1800
16th to endNight
1111122383%
1910
September1st to 15thNight
1111123481%
1880
16th to endNight
1111191%
1890
October1st to 15thNight
1112245%79%
1815
16th to endNight
111113481%
2126
November1st to 15thNight
11112335%79%
2275
16th to endNight
111112236%75%
2340
December1st to 15thNight
312323349%65%
2340
16th to endNight
311221335%8%65%
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
14%7%10%14%27%24%
1612
16th to endDay
18%7%11%13%24%24%
1881
February1st to 15thDay
14%7%9%14%26%27%
1751
16th to endDay
17%10%11%15%29%16%
1579
March1st to 15thDay
10%5%11%19%28%25%
1809
16th to endDay
11%8%12%18%29%20%
2166
April1st to 15thDay
12%6%11%15%34%19%
2149
16th to endDay
5%49%18%31%30%
2160
May1st to 15thDay
6%39%14%31%33%
2322
16th to endDay
6%37%15%37%30%
2432
June1st to 15thDay
5%26%9%23%52%
2340
16th to endDay
6%12413%72%
2340
July1st to 15thDay
11%36%8%20%48%
2201
16th to endDay
15%6%8%15%21%32%
2298
August1st to 15thDay
8%25%9%22%51%
2146
16th to endDay
9%35%8%27%45%
2292
September1st to 15thDay
10%37%7%23%46%
2079
16th to endDay
6%146%26%54%
1882
October1st to 15thDay
8%48%11%29%38%
1815
16th to endDay
7%5%7%9%23%46%
1744
November1st to 15thDay
10%39%12%30%33%
1584
16th to endDay
12%5%10%11%28%33%
1620
December1st to 15thDay
17%7%12%17%22%22%
1620
16th to endDay
17%10%11%17%25%17%
1728
January1st to 15thNight
14%7%10%15%23%28%
2327
16th to endNight
18%6%12%14%20%27%
2342
February1st to 15thNight
13%8%11%13%23%29%
2112
16th to endNight
15%11%12%17%24%18%
1895
March1st to 15thNight
11%7%13%17%24%24%
2151
16th to endNight
9%9%12%20%28%19%
2055
April1st to 15thNight
11%7%12%20%29%18%
1799
16th to endNight
6%5%10%17%34%25%
1800
May1st to 15thNight
3410%18%33%29%
1628
16th to endNight
4310%16%42%22%
1685
June1st to 15thNight
43412%25%49%
1620
16th to endNight
426%17%69%
1620
July1st to 15thNight
8%16%8%19%55%
1530
16th to endNight
11%5%8%17%25%31%
1604
August1st to 15thNight
6%1411%27%48%
1790
16th to endNight
7%15%9%30%46%
1910
September1st to 15thNight
6%26%9%25%48%
1880
16th to endNight
3138%29%53%
1890
October1st to 15thNight
7%48%10%34%33%
1815
16th to endNight
6%49%8%23%47%
2126
November1st to 15thNight
8%48%12%32%33%
2275
16th to endNight
10%5%10%15%24%33%
2340
December1st to 15thNight
14%9%13%15%22%24%
2340
16th to endNight
17%9%13%15%25%18%
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
5%14%40%36%3
90
16th to endDay
6%21%34%29%5%2
249
February1st to 15thDay
121%32%30%11%1
266
16th to endDay
5%28%36%21%7%
238
March1st to 15thDay
422%36%21%12%1
270
16th to endDay
225%38%22%8%1
288
April1st to 15thDay
5%27%36%19%8%2
269
16th to endDay
129%40%20%7%
270
May1st to 15thDay
219%41%26%6%3
288
16th to endDay
119%40%28%9%1
330
June1st to 15thDay
212%42%28%12%1
315
16th to endDay
2438%34%15%4
315
July1st to 15thDay
1324%47%19%3
305
16th to endDay
1116%52%19%7%
327
August1st to 15thDay
328%44%18%4
315
16th to endDay
120%52%17%7%
332
September1st to 15thDay
3235%44%13%
315
16th to endDay
10%31%42%13%2
280
October1st to 15thDay
115%40%32%10%
255
16th to endDay
18%33%32%21%2
190
November1st to 15thDay
14%21%26%28%8%
90
16th to endDay
14%38%28%17%
90
December1st to 15thDay
28%28%43%14%2
90
16th to endDay
213%42%37%4
96
January1st to 15thNight
15%28%37%18%7%
720
16th to endNight
45%30%35%21%3
768
February1st to 15thNight
25%31%34%22%4
704
16th to endNight
38%36%33%14%3
632
March1st to 15thNight
18%32%34%18%4
720
16th to endNight
11%31%34%18%4
768
April1st to 15thNight
113%39%27%15%2
719
16th to endNight
10%37%28%18%4
720
May1st to 15thNight
9%33%38%16%1
548
16th to endNight
10%37%30%20%1
563
June1st to 15thNight
5%36%37%17%1
540
16th to endNight
26%53%18%
540
July1st to 15thNight
1111%48%34%1
510
16th to endNight
210%48%36%1
576
August1st to 15thNight
9%41%41%5%
717
16th to endNight
16%31%48%10%
764
September1st to 15thNight
9%36%45%7%
720
16th to endNight
214%35%38%8%
683
October1st to 15thNight
1326%33%30%4
660
16th to endNight
218%36%30%10%
704
November1st to 15thNight
223%36%29%7%
700
16th to endNight
1325%35%25%8%
720
December1st to 15thNight
2429%37%21%4
720
16th to endNight
5%8%31%33%16%4
768
Page generated at 2017-09-23 03:43:35. Version ac04

Copyright 2017 A. Danko


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