Seminole Canyon State Park & Historic Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Seminole Canyon State Park & Historic Site clear sky chart from 2005-11-05 to 2018-08-29.

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
46%
16620
30%
50732
18%
16576
58%
16576
37%
26824

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
40%
893
31%
2444
15%
892
51%
892
33%
1423
January16th to endNight
43%
832
34%
2496
17%
832
57%
832
36%
1348
February1st to 15thNight
37%
764
31%
2287
15%
758
51%
758
32%
1227
February16th to endNight
29%
684
31%
2050
10%
684
47%
684
35%
1091
March1st to 15thNight
27%
745
30%
2305
10%
745
45%
745
32%
1219
March16th to endNight
27%
624
28%
2280
14%
624
47%
624
31%
1154
April1st to 15thNight
22%
584
32%
1948
11%
584
46%
584
33%
994
April16th to endNight
24%
579
32%
1929
13%
579
51%
579
36%
977
May1st to 15thNight
25%
584
25%
1848
12%
584
43%
584
30%
1031
May16th to endNight
29%
610
25%
1828
12%
609
47%
609
32%
1041
June1st to 15thNight
44%
585
26%
1755
15%
585
60%
585
48%
827
June16th to endNight
56%
585
23%
1755
21%
585
62%
585
40%
939
July1st to 15thNight
67%
555
23%
1665
24%
555
70%
555
40%
911
July16th to endNight
71%
612
30%
1890
32%
579
81%
579
47%
883
August1st to 15thNight
81%
575
31%
1908
37%
572
84%
572
52%
843
August16th to endNight
75%
615
28%
2050
30%
615
78%
615
40%
1055
September1st to 15thNight
74%
540
23%
1917
27%
540
75%
540
34%
1031
September16th to endNight
60%
537
25%
1980
24%
537
66%
537
28%
1102
October1st to 15thNight
60%
540
34%
1980
30%
540
68%
540
40%
945
October16th to endNight
60%
637
40%
2173
28%
637
71%
637
48%
960
November1st to 15thNight
50%
950
30%
2470
13%
950
59%
950
43%
1357
November16th to endNight
48%
975
38%
2535
16%
975
60%
975
44%
1333
December1st to 15thNight
43%
975
31%
2535
15%
975
52%
975
34%
1527
December16th to endNight
36%
1040
30%
2704
11%
1040
49%
1040
33%
1606

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
9%413323347%56%
51494
Night
8%313323347%59%
50946
Cloud CoverDay
8%413323347%56%
51492
Night
7%313323347%59%
50946
TransparencyDay
28%5%10%21%21%12%
51204
Night
24%410%21%22%15%
50739
SeeingDay
9%9%20%35%20%3
6531
Night
8%16%25%36%12%
16626

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
11%5%13423235%56%
1834
16th to endDay
10%5%11323345%58%
2080
February1st to 15thDay
8%6%23323235%59%
1900
16th to endDay
7%5%13213346%58%
1710
March1st to 15thDay
12%5%13313446%53%
1982
16th to endDay
11%313213336%57%
2291
April1st to 15thDay
9%314313346%57%
2330
16th to endDay
9%31322335%6%56%
2306
May1st to 15thDay
11%423322447%53%
2430
16th to endDay
13%42332335%8%49%
2638
June1st to 15thDay
5%212213448%62%
2535
16th to endDay
6%32332446%9%53%
2535
July1st to 15thDay
9%3123345%5%8%52%
2535
16th to endDay
5%21231345%9%59%
2508
August1st to 15thDay
22232245%9%64%
2294
16th to endDay
5%3134345%410%53%
2449
September1st to 15thDay
9%5%245%35%6%6%7%44%
2043
16th to endDay
12%41333445%6%50%
1980
October1st to 15thDay
10%31331325%6%57%
1980
16th to endDay
7%31321223466%
2034
November1st to 15thDay
10%413312245%59%
1718
16th to endDay
10%422212225%62%
1755
December1st to 15thDay
16%6%1331225%450%
1755
16th to endDay
12%7%24223337%50%
1872
January1st to 15thNight
9%5%24323245%55%
2444
16th to endNight
11%313312346%57%
2496
February1st to 15thNight
8%5%13313336%59%
2282
16th to endNight
9%31231245%6%59%
2050
March1st to 15thNight
9%5%12213345%58%
2305
16th to endNight
8%31332235%6%58%
2280
April1st to 15thNight
8%312323347%59%
1948
16th to endNight
8%31332224462%
1929
May1st to 15thNight
9%414324446%54%
1848
16th to endNight
10%22332336%8%52%
1827
June1st to 15thNight
21122335%9%66%
1755
16th to endNight
42122245%6%11%55%
1755
July1st to 15thNight
6%21333435%11%55%
1755
16th to endNight
5%11221235%8%63%
2009
August1st to 15thNight
2122124410%66%
1919
16th to endNight
6%21232446%10%55%
2050
September1st to 15thNight
5%3134345%6%9%53%
1917
16th to endNight
10%3234235%6%8%48%
1980
October1st to 15thNight
7%213213346%63%
1980
16th to endNight
5%21221224471%
2173
November1st to 15thNight
8%312212236%64%
2470
16th to endNight
7%22212235%68%
2535
December1st to 15thNight
12%5%2331245%7%52%
2535
16th to endNight
10%6%13313346%55%
2704

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%23413335%55%
1834
16th to endDay
9%412223345%58%
2080
February1st to 15thDay
7%6%23323235%59%
1900
16th to endDay
6%5%23213445%58%
1710
March1st to 15thDay
11%5%23313345%54%
1982
16th to endDay
9%413223336%57%
2289
April1st to 15thDay
8%323323346%57%
2330
16th to endDay
8%413214447%57%
2306
May1st to 15thDay
10%5%14322448%53%
2430
16th to endDay
11%5%2432335%9%49%
2638
June1st to 15thDay
4212313448%62%
2535
16th to endDay
6%3233235%6%9%53%
2535
July1st to 15thDay
9%31332446%8%51%
2535
16th to endDay
5%21232345%9%59%
2508
August1st to 15thDay
221232345%9%64%
2294
16th to endDay
4314435%5%5%9%52%
2449
September1st to 15thDay
9%4245%35%5%6%7%44%
2043
16th to endDay
10%5%1442445%6%49%
1980
October1st to 15thDay
8%41342325%6%57%
1980
16th to endDay
6%313212235%66%
2034
November1st to 15thDay
8%5%13322236%60%
1718
16th to endDay
8%5%13223235%62%
1755
December1st to 15thDay
14%7%23313345%49%
1755
16th to endDay
11%8%23322336%51%
1872
January1st to 15thNight
8%5%24413335%56%
2444
16th to endNight
11%313312346%57%
2496
February1st to 15thNight
7%5%24312336%59%
2282
16th to endNight
8%313313446%59%
2050
March1st to 15thNight
9%5%1321235%6%58%
2305
16th to endNight
8%314312347%59%
2280
April1st to 15thNight
7%312313347%60%
1948
16th to endNight
7%323222345%62%
1929
May1st to 15thNight
8%424324346%54%
1848
16th to endNight
8%42332346%9%51%
1827
June1st to 15thNight
21122345%10%66%
1755
16th to endNight
42123245%6%11%56%
1755
July1st to 15thNight
5%213325%35%10%55%
1755
16th to endNight
41222245%8%63%
2009
August1st to 15thNight
1122123410%67%
1919
16th to endNight
5%21332446%10%55%
2050
September1st to 15thNight
5%31343445%10%53%
1917
16th to endNight
10%32342446%8%48%
1980
October1st to 15thNight
7%213223246%63%
1980
16th to endNight
431221224471%
2173
November1st to 15thNight
7%313212236%64%
2470
16th to endNight
6%212212335%68%
2535
December1st to 15thNight
11%5%2421335%8%51%
2535
16th to endNight
9%6%14313346%55%
2704

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
32%35%19%25%13%
1835
16th to endDay
27%37%15%28%16%
2080
February1st to 15thDay
29%36%16%21%21%
1901
16th to endDay
26%48%15%27%17%
1710
March1st to 15thDay
32%47%16%18%19%
1982
16th to endDay
28%49%17%19%20%
2291
April1st to 15thDay
28%47%16%21%21%
2330
16th to endDay
27%47%19%18%21%
2306
May1st to 15thDay
30%5%10%21%20%12%
2430
16th to endDay
33%6%9%22%19%8%
2642
June1st to 15thDay
20%5%12%27%25%8%
2535
16th to endDay
26%8%16%22%19%6%
2535
July1st to 15thDay
28%8%14%28%16%3
2396
16th to endDay
18%7%18%32%20%1
2364
August1st to 15thDay
16%6%16%36%20%2
2281
16th to endDay
27%8%17%24%18%4
2449
September1st to 15thDay
36%8%14%21%15%4
2043
16th to endDay
34%6%11%16%22%8%
1980
October1st to 15thDay
27%6%12%23%19%10%
1980
16th to endDay
21%36%12%31%24%
2034
November1st to 15thDay
28%39%24%19%13%
1718
16th to endDay
27%35%12%26%24%
1755
December1st to 15thDay
36%36%17%23%12%
1755
16th to endDay
34%36%17%25%11%
1872
January1st to 15thNight
31%25%17%24%18%
2444
16th to endNight
27%37%14%26%21%
2496
February1st to 15thNight
27%37%16%20%25%
2292
16th to endNight
26%47%15%26%19%
2050
March1st to 15thNight
27%39%17%20%20%
2305
16th to endNight
26%411%17%19%19%
2280
April1st to 15thNight
24%410%18%19%22%
1948
16th to endNight
25%38%23%21%18%
1929
May1st to 15thNight
30%411%20%19%13%
1849
16th to endNight
28%6%12%22%22%7%
1829
June1st to 15thNight
14%5%15%27%28%8%
1755
16th to endNight
22%7%16%24%22%7%
1755
July1st to 15thNight
24%6%16%27%20%4
1665
16th to endNight
15%7%16%33%24%2
1890
August1st to 15thNight
13%6%16%31%28%3
1908
16th to endNight
22%7%17%29%19%4
2050
September1st to 15thNight
26%8%16%23%19%5%
1917
16th to endNight
31%6%14%21%15%9%
1980
October1st to 15thNight
22%5%13%27%19%12%
1980
16th to endNight
17%37%15%29%26%
2173
November1st to 15thNight
22%48%23%25%15%
2470
16th to endNight
19%37%16%24%28%
2535
December1st to 15thNight
31%38%19%21%16%
2535
16th to endNight
29%47%17%23%17%
2704

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
15%7%22%37%17%
135
16th to endDay
15%7%29%25%20%1
144
February1st to 15thDay
12%30%33%17%5%
135
16th to endDay
13%6%45%26%7%
120
March1st to 15thDay
17%437%33%6%
135
16th to endDay
7%6%31%44%8%2
147
April1st to 15thDay
6%17%43%29%3
329
16th to endDay
5%18%42%26%6%
318
May1st to 15thDay
12%17%38%26%5%
447
16th to endDay
15%14%28%31%8%
597
June1st to 15thDay
411%21%47%12%2
570
16th to endDay
5%11%14%42%22%4
570
July1st to 15thDay
8%7%6%40%31%4
550
16th to endDay
28%339%40%5%
429
August1st to 15thDay
45%435%41%9%
359
16th to endDay
5%45%38%38%6%
385
September1st to 15thDay
436%36%41%8%
198
16th to endDay
22%339%23%10%
135
October1st to 15thDay
12%10%34%39%2
135
16th to endDay
12%220%34%26%4
144
November1st to 15thDay
26%416%30%19%2
135
16th to endDay
14%8%25%26%14%9%
135
December1st to 15thDay
22%422%24%20%5%
135
16th to endDay
20%8%25%27%18%
144
January1st to 15thNight
11%17%25%35%8%
897
16th to endNight
7%19%26%37%9%
832
February1st to 15thNight
11%20%28%30%9%
764
16th to endNight
10%18%39%29%2
684
March1st to 15thNight
14%19%36%26%3
745
16th to endNight
7%22%41%25%3
624
April1st to 15thNight
8%20%46%21%2
584
16th to endNight
6%21%45%23%3
579
May1st to 15thNight
9%20%43%24%2
585
16th to endNight
9%18%40%24%6%
611
June1st to 15thNight
216%34%42%4
585
16th to endNight
315%21%45%11%
585
July1st to 15thNight
5%10%10%50%20%1
555
16th to endNight
215%7%52%21%
612
August1st to 15thNight
18%450%34%1
575
16th to endNight
5%7%6%48%29%2
615
September1st to 15thNight
48%6%45%31%3
540
16th to endNight
11%9%10%38%28%
537
October1st to 15thNight
7%8%20%43%18%
540
16th to endNight
5%9%22%42%18%1
637
November1st to 15thNight
8%15%22%36%15%1
950
16th to endNight
8%18%21%36%13%
975
December1st to 15thNight
15%18%19%33%12%
975
16th to endNight
12%20%26%32%7%
1040
Page generated at 2018-08-30 04:34:21. Version ac04

Copyright 2018 A. Danko


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