Shades State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shades State Park clear sky chart from 2005-11-05 to 2018-04-23.

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
40%
16732
18%
49478
12%
16692
46%
16692
24%
32968

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
22%
974
15%
2716
6%
970
30%
970
17%
2014
January16th to endNight
21%
1040
13%
2873
6%
1040
28%
1040
17%
2149
February1st to 15thNight
22%
766
12%
2297
5%
766
28%
766
16%
1672
February16th to endNight
24%
683
15%
2049
7%
683
31%
683
17%
1482
March1st to 15thNight
26%
780
15%
2340
8%
780
32%
780
19%
1636
March16th to endNight
28%
728
16%
2197
7%
728
37%
728
20%
1536
April1st to 15thNight
31%
584
18%
1947
10%
584
43%
584
21%
1271
April16th to endNight
36%
558
19%
1786
12%
558
45%
558
24%
1166
May1st to 15thNight
35%
540
15%
1620
8%
540
42%
540
21%
1143
May16th to endNight
52%
561
17%
1588
13%
561
56%
561
27%
1053
June1st to 15thNight
60%
540
19%
1440
13%
540
64%
540
38%
873
June16th to endNight
62%
540
19%
1440
15%
540
64%
540
35%
906
July1st to 15thNight
66%
510
16%
1360
13%
510
67%
510
38%
832
July16th to endNight
75%
564
26%
1418
19%
531
79%
531
48%
781
August1st to 15thNight
74%
539
22%
1654
22%
536
75%
536
38%
930
August16th to endNight
70%
573
24%
1910
24%
573
74%
573
36%
1045
September1st to 15thNight
64%
580
26%
1840
25%
580
67%
580
34%
1059
September16th to endNight
62%
717
28%
1980
22%
717
65%
717
36%
1185
October1st to 15thNight
53%
720
28%
2006
22%
720
59%
720
35%
1222
October16th to endNight
33%
768
21%
2457
15%
768
42%
768
24%
1547
November1st to 15thNight
37%
760
25%
2471
17%
760
49%
760
27%
1483
November16th to endNight
30%
780
20%
2535
13%
780
40%
780
20%
1691
December1st to 15thNight
24%
887
11%
2642
5%
887
30%
887
16%
1973
December16th to endNight
17%
1040
11%
2912
4%
1040
24%
1040
13%
2319

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
14%7%36%5%3445%7%36%
50040
Night
14%7%36%5%2445%7%39%
49648
Cloud CoverDay
14%7%35%5%3445%7%36%
50049
Night
14%7%35%5%24446%39%
49653
TransparencyDay
46%5%12%21%12%2
49728
Night
44%411%21%14%2
49478
SeeingDay
17%6%25%24%18%7%
6569
Night
18%7%27%30%14%1
16738

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
19%13%5%9%6%34446%24%
1552
16th to endDay
13%14%6%8%5%34347%27%
1700
February1st to 15thDay
14%12%5%8%7%45%44427%
1894
16th to endDay
18%13%6%7%5%34337%27%
1710
March1st to 15thDay
19%8%5%7%5%45%346%29%
1940
16th to endDay
18%10%47%5%24446%30%
2387
April1st to 15thDay
19%8%35%423447%36%
2331
16th to endDay
18%8%35%5%24447%35%
2288
May1st to 15thDay
21%8%36%5%34447%30%
2331
16th to endDay
12%5%26%7%35%5%6%7%37%
2524
June1st to 15thDay
9%5%245%245%5%8%44%
2520
16th to endDay
9%425%5%35%5%6%9%40%
2520
July1st to 15thDay
10%5%246%35%6%6%9%38%
2520
16th to endDay
5%4245%37%6%7%11%41%
2652
August1st to 15thDay
7%4245%35%5%6%9%44%
2292
16th to endDay
8%325%5%345%6%9%44%
2292
September1st to 15thDay
11%5%245%35%5%5%6%43%
2107
16th to endDay
12%4234235%6%6%48%
1980
October1st to 15thDay
16%5%2443445%6%41%
1953
16th to endDay
16%7%25%425%445%39%
1767
November1st to 15thDay
15%7%25%423346%45%
1717
16th to endDay
18%8%45%42335%5%37%
1755
December1st to 15thDay
18%12%49%7%24345%27%
1644
16th to endDay
20%15%6%7%7%2434422%
1664
January1st to 15thNight
18%10%48%6%34335%31%
2716
16th to endNight
14%11%6%8%7%34335%30%
2873
February1st to 15thNight
17%12%5%8%433346%31%
2295
16th to endNight
17%10%47%5%3434432%
2049
March1st to 15thNight
17%8%46%5%2346%6%34%
2327
16th to endNight
18%8%46%5%23446%35%
2197
April1st to 15thNight
17%7%36%42335%7%38%
1947
16th to endNight
16%6%35%4245%5%6%39%
1786
May1st to 15thNight
17%7%37%5%2436%7%34%
1620
16th to endNight
11%425%6%45%5%5%9%40%
1586
June1st to 15thNight
9%42442335%9%49%
1440
16th to endNight
8%424426%5%7%11%44%
1440
July1st to 15thNight
7%423435%5%7%10%46%
1440
16th to endNight
332342335%10%55%
1514
August1st to 15thNight
6%31442447%9%50%
1665
16th to endNight
6%4145%2346%8%52%
1910
September1st to 15thNight
10%42432346%8%49%
1840
16th to endNight
10%41433435%8%50%
1980
October1st to 15thNight
11%424323446%51%
2006
16th to endNight
17%6%24424445%43%
2457
November1st to 15thNight
13%5%345%23347%46%
2471
16th to endNight
18%9%35%423346%37%
2535
December1st to 15thNight
19%12%5%8%5%24335%29%
2642
16th to endNight
22%12%5%9%5%3443423%
2912

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
19%13%49%6%34345%24%
1552
16th to endDay
13%14%6%8%6%3435%6%27%
1700
February1st to 15thDay
14%12%5%8%8%45%345%27%
1894
16th to endDay
18%13%5%7%5%33246%27%
1710
March1st to 15thDay
20%9%5%7%5%34345%29%
1950
16th to endDay
18%10%5%6%5%34446%29%
2386
April1st to 15thDay
19%8%35%423447%36%
2331
16th to endDay
18%9%25%5%24347%35%
2288
May1st to 15thDay
21%8%37%434447%30%
2331
16th to endDay
12%5%35%6%35%5%5%7%37%
2524
June1st to 15thDay
9%5%345%245%5%8%45%
2520
16th to endDay
9%425%6%35%5%6%9%40%
2520
July1st to 15thDay
10%5%25%5%36%6%6%9%39%
2520
16th to endDay
6%3245%36%6%8%10%41%
2652
August1st to 15thDay
8%324445%5%5%9%45%
2292
16th to endDay
8%4145%35%5%6%8%45%
2292
September1st to 15thDay
12%5%245%35%45%7%43%
2107
16th to endDay
12%42332346%6%48%
1980
October1st to 15thDay
15%5%245%4445%6%41%
1953
16th to endDay
17%8%24425%446%39%
1767
November1st to 15thDay
15%6%23424336%46%
1717
16th to endDay
18%7%45%42335%5%37%
1755
December1st to 15thDay
19%12%39%7%24345%27%
1644
16th to endDay
20%15%5%8%6%3434422%
1664
January1st to 15thNight
18%11%47%6%2433431%
2716
16th to endNight
15%11%6%8%6%34335%30%
2873
February1st to 15thNight
17%12%6%7%5%23345%31%
2288
16th to endNight
17%10%48%6%34435%32%
2049
March1st to 15thNight
18%8%45%5%2345%7%34%
2340
16th to endNight
18%8%36%6%23446%35%
2197
April1st to 15thNight
16%7%35%42435%6%38%
1947
16th to endNight
17%6%26%42445%6%39%
1786
May1st to 15thNight
17%7%36%5%25%35%7%35%
1619
16th to endNight
11%425%6%36%5%5%9%40%
1586
June1st to 15thNight
9%425%42335%9%49%
1440
16th to endNight
8%325%325%5%7%11%44%
1440
July1st to 15thNight
7%3234346%6%10%46%
1440
16th to endNight
332342337%10%55%
1514
August1st to 15thNight
6%3134345%6%9%50%
1665
16th to endNight
6%4245%2445%8%52%
1910
September1st to 15thNight
10%5%2333345%6%50%
1840
16th to endNight
10%42342335%8%50%
1980
October1st to 15thNight
11%415%41345%6%51%
2006
16th to endNight
17%6%24423436%43%
2457
November1st to 15thNight
13%5%24423337%47%
2471
16th to endNight
18%9%45%423345%37%
2535
December1st to 15thNight
19%11%5%7%6%25%34429%
2642
16th to endNight
22%12%5%9%5%2443423%
2912

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
61%49%15%8%
1553
16th to endDay
57%5%13%17%5%
1700
February1st to 15thDay
59%411%15%7%1
1896
16th to endDay
58%311%18%6%
1710
March1st to 15thDay
55%412%18%7%
1950
16th to endDay
54%5%13%20%5%1
2387
April1st to 15thDay
47%412%21%12%
2331
16th to endDay
48%413%18%10%4
2288
May1st to 15thDay
52%6%11%19%9%
2331
16th to endDay
44%7%11%18%15%2
2528
June1st to 15thDay
35%5%13%24%17%2
2520
16th to endDay
38%6%14%20%16%3
2520
July1st to 15thDay
41%6%11%22%16%2
2371
16th to endDay
33%8%17%25%12%1
2485
August1st to 15thDay
33%6%14%25%18%1
2279
16th to endDay
33%7%13%23%15%6%
2292
September1st to 15thDay
39%6%10%22%16%4
2107
16th to endDay
34%5%9%25%20%3
1980
October1st to 15thDay
41%5%10%24%15%2
1953
16th to endDay
44%411%24%13%
1767
November1st to 15thDay
40%311%20%18%4
1717
16th to endDay
48%49%23%12%1
1755
December1st to 15thDay
59%410%18%7%
1644
16th to endDay
64%410%15%4
1664
January1st to 15thNight
55%48%19%11%1
2716
16th to endNight
56%312%19%7%
2873
February1st to 15thNight
55%412%16%9%1
2297
16th to endNight
54%311%19%9%
2049
March1st to 15thNight
49%6%10%20%10%1
2340
16th to endNight
49%5%12%22%8%1
2197
April1st to 15thNight
45%49%23%14%1
1947
16th to endNight
44%49%20%14%6%
1786
May1st to 15thNight
47%6%12%20%12%
1620
16th to endNight
39%9%12%17%16%4
1588
June1st to 15thNight
32%5%12%28%19%2
1440
16th to endNight
32%7%13%21%18%5%
1440
July1st to 15thNight
29%7%16%22%18%4
1360
16th to endNight
23%5%15%33%20%3
1418
August1st to 15thNight
27%7%14%25%22%2
1654
16th to endNight
28%6%11%26%20%6%
1910
September1st to 15thNight
32%5%10%24%20%6%
1840
16th to endNight
32%5%9%23%25%4
1980
October1st to 15thNight
33%5%9%25%22%3
2006
16th to endNight
42%310%24%16%2
2457
November1st to 15thNight
38%38%24%19%5%
2471
16th to endNight
48%311%23%13%
2535
December1st to 15thNight
58%310%17%9%
2642
16th to endNight
63%49%15%6%
2912

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
30%11%31%17%8%
135
16th to endDay
16%19%40%22%
144
February1st to 15thDay
24%15%42%14%2
135
16th to endDay
30%14%31%17%6%
120
March1st to 15thDay
28%18%36%15%1
135
16th to endDay
28%8%32%20%8%
337
April1st to 15thDay
24%12%29%21%10%2
330
16th to endDay
24%7%28%21%12%5%
289
May1st to 15thDay
25%10%23%26%10%4
288
16th to endDay
15%429%23%19%8%
424
June1st to 15thDay
13%224%31%20%6%
495
16th to endDay
12%431%27%16%6%
495
July1st to 15thDay
14%122%28%21%12%
475
16th to endDay
7%212%30%30%16%
512
August1st to 15thDay
10%18%21%35%22%
313
16th to endDay
9%113%22%38%14%
332
September1st to 15thDay
14%311%26%30%13%
315
16th to endDay
13%412%21%33%13%
314
October1st to 15thDay
15%425%26%22%5%
288
16th to endDay
23%9%36%23%7%
144
November1st to 15thDay
17%10%23%26%14%7%
135
16th to endDay
26%10%37%19%5%
135
December1st to 15thDay
16%20%36%18%7%
135
16th to endDay
27%16%43%10%1
144
January1st to 15thNight
23%14%34%24%4
975
16th to endNight
19%13%37%26%2
1040
February1st to 15thNight
21%12%36%25%3
769
16th to endNight
22%10%37%25%4
683
March1st to 15thNight
22%11%36%25%4
780
16th to endNight
21%9%34%25%6%1
728
April1st to 15thNight
19%11%33%27%8%
584
16th to endNight
18%6%33%29%10%1
558
May1st to 15thNight
20%6%29%31%11%
540
16th to endNight
13%421%35%22%1
563
June1st to 15thNight
11%218%47%18%
540
16th to endNight
9%120%46%22%
540
July1st to 15thNight
8%116%42%29%1
510
16th to endNight
4210%39%38%5%
564
August1st to 15thNight
7%10%43%33%5%
539
16th to endNight
6%112%31%42%4
573
September1st to 15thNight
12%216%35%28%5%
580
16th to endNight
12%314%30%35%3
717
October1st to 15thNight
14%5%21%34%20%4
720
16th to endNight
23%9%30%26%10%
768
November1st to 15thNight
16%8%33%27%11%1
760
16th to endNight
22%12%30%26%8%
780
December1st to 15thNight
26%10%33%23%6%1
887
16th to endNight
29%10%34%22%4
1040
Page generated at 2018-04-24 10:03:01. Version ac04

Copyright 2018 A. Danko


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