Big Spring State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Big Spring State Park clear sky chart from 2005-11-05 to 2017-09-18.

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
53%
15557
32%
46988
20%
15514
64%
15514
46%
23679

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
44%
894
33%
2324
16%
892
56%
892
48%
1283
January16th to endNight
44%
768
40%
2304
20%
768
62%
768
47%
1133
February1st to 15thNight
44%
702
33%
2111
17%
699
59%
699
43%
1083
February16th to endNight
29%
632
34%
1894
11%
632
49%
632
43%
967
March1st to 15thNight
36%
702
31%
2142
13%
702
52%
702
39%
1130
March16th to endNight
31%
576
31%
2075
16%
576
50%
576
39%
972
April1st to 15thNight
27%
539
33%
1798
12%
539
52%
539
42%
865
April16th to endNight
33%
540
34%
1800
17%
540
58%
540
48%
817
May1st to 15thNight
35%
540
28%
1655
16%
539
53%
539
46%
823
May16th to endNight
48%
562
27%
1684
18%
561
64%
561
45%
876
June1st to 15thNight
59%
540
26%
1620
20%
540
70%
540
54%
778
June16th to endNight
71%
540
27%
1620
27%
540
76%
540
57%
769
July1st to 15thNight
79%
510
23%
1530
25%
510
80%
510
45%
813
July16th to endNight
88%
564
31%
1651
34%
531
89%
531
56%
767
August1st to 15thNight
86%
539
30%
1789
38%
536
87%
536
49%
837
August16th to endNight
83%
573
29%
1910
34%
573
84%
573
44%
966
September1st to 15thNight
75%
540
26%
1894
29%
540
77%
540
37%
1007
September16th to endNight
71%
501
31%
1848
32%
501
75%
501
35%
963
October1st to 15thNight
60%
495
37%
1815
31%
495
71%
495
48%
802
October16th to endNight
60%
665
40%
2073
24%
665
71%
665
57%
918
November1st to 15thNight
55%
875
36%
2275
14%
875
65%
875
59%
1141
November16th to endNight
49%
900
36%
2340
16%
900
61%
900
49%
1266
December1st to 15thNight
44%
900
37%
2340
16%
900
57%
900
47%
1295
December16th to endNight
44%
960
35%
2496
15%
960
56%
960
44%
1408

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
6%313323346%59%
47793
Night
5%212323347%62%
47192
Cloud CoverDay
6%313323346%59%
47791
Night
5%312323347%62%
47192
TransparencyDay
24%38%21%25%15%
47497
Night
21%38%21%26%17%
46991
SeeingDay
6%421%34%25%6%
5492
Night
6%5%31%38%16%
15563

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
10%5%12312235%60%
1624
16th to endDay
7%413212335%62%
1920
February1st to 15thDay
5%312213345%65%
1750
16th to endDay
7%5%2221223465%
1580
March1st to 15thDay
8%423324445%56%
1818
16th to endDay
6%412222345%63%
2146
April1st to 15thDay
6%213323345%63%
2150
16th to endDay
4212312325%68%
2160
May1st to 15thDay
9%313324345%57%
2293
16th to endDay
7%213334446%56%
2430
June1st to 15thDay
2112224347%66%
2340
16th to endDay
4213325%35%8%57%
2340
July1st to 15thDay
7%312345%6%5%9%49%
2340
16th to endDay
2113425%5%6%9%54%
2401
August1st to 15thDay
211242445%9%61%
2160
16th to endDay
5%325%5%46%6%6%9%45%
2292
September1st to 15thDay
9%425%5%3345%9%46%
2064
16th to endDay
9%314434446%54%
1837
October1st to 15thDay
8%413313346%61%
1815
16th to endDay
431221222374%
1782
November1st to 15thDay
4413211235%69%
1583
16th to endDay
8%32221213467%
1620
December1st to 15thDay
9%5%13213336%58%
1620
16th to endDay
7%5%13322335%59%
1728
January1st to 15thNight
7%413312235%63%
2324
16th to endNight
6%313312225%66%
2304
February1st to 15thNight
7%31331332463%
2102
16th to endNight
6%213324346%62%
1894
March1st to 15thNight
7%42332345%6%56%
2142
16th to endNight
6%322223346%62%
2075
April1st to 15thNight
5%213213347%62%
1798
16th to endNight
4212212335%69%
1800
May1st to 15thNight
4213223447%62%
1655
16th to endNight
42124145%7%9%57%
1683
June1st to 15thNight
11132436%8%66%
1620
16th to endNight
1122145%6%10%63%
1620
July1st to 15thNight
4213325%45%10%55%
1620
16th to endNight
111122347%11%61%
1764
August1st to 15thNight
21123234410%62%
1800
16th to endNight
32133235%8%9%55%
1910
September1st to 15thNight
8%31343345%7%53%
1894
16th to endNight
8%313424447%54%
1848
October1st to 15thNight
6%211212348%64%
1815
16th to endNight
22221222474%
2073
November1st to 15thNight
322212346%68%
2275
16th to endNight
6%31221343466%
2340
December1st to 15thNight
9%312212246%61%
2340
16th to endNight
7%423323445%59%
2496

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
9%5%13322236%60%
1624
16th to endDay
7%423212335%62%
1920
February1st to 15thDay
5%222313335%65%
1750
16th to endDay
7%42321323464%
1580
March1st to 15thDay
7%5%14323446%56%
1818
16th to endDay
6%322213345%63%
2144
April1st to 15thDay
6%213313345%63%
2150
16th to endDay
4312213336%68%
2160
May1st to 15thDay
9%313324445%57%
2293
16th to endDay
7%21333445%6%56%
2430
June1st to 15thDay
2212314347%66%
2340
16th to endDay
4213325%45%8%57%
2340
July1st to 15thDay
6%313326%6%6%8%49%
2340
16th to endDay
2213435%6%6%9%55%
2401
August1st to 15thDay
211342445%9%61%
2160
16th to endDay
5%315%6%36%6%6%8%46%
2292
September1st to 15thDay
9%4245%3345%9%45%
2064
16th to endDay
9%324424445%54%
1837
October1st to 15thDay
8%413312336%60%
1815
16th to endDay
43221222373%
1782
November1st to 15thDay
4313212235%69%
1583
16th to endDay
8%31311223467%
1620
December1st to 15thDay
9%5%13123246%58%
1620
16th to endDay
7%5%13423335%59%
1728
January1st to 15thNight
7%41331323463%
2324
16th to endNight
6%313312235%66%
2304
February1st to 15thNight
7%323313325%63%
2102
16th to endNight
6%213323336%62%
1894
March1st to 15thNight
7%42332345%7%56%
2142
16th to endNight
5%312313346%62%
2075
April1st to 15thNight
5%223313346%63%
1798
16th to endNight
4212212335%69%
1800
May1st to 15thNight
5%312323346%63%
1655
16th to endNight
4112315%47%8%58%
1683
June1st to 15thNight
11232445%7%66%
1620
16th to endNight
1122145%6%11%61%
1620
July1st to 15thNight
431332445%11%54%
1620
16th to endNight
1123235%6%11%61%
1764
August1st to 15thNight
21123343410%62%
1800
16th to endNight
2233335%8%10%54%
1910
September1st to 15thNight
8%313425%35%8%53%
1894
16th to endNight
7%4233245%5%7%54%
1848
October1st to 15thNight
6%211212448%64%
1815
16th to endNight
221221222474%
2073
November1st to 15thNight
312312346%69%
2275
16th to endNight
7%31222343466%
2340
December1st to 15thNight
9%313212336%61%
2340
16th to endNight
6%413323446%58%
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
27%2422%29%14%
1625
16th to endDay
24%25%17%32%17%
1920
February1st to 15thDay
20%35%20%26%23%
1751
16th to endDay
24%2218%30%21%
1580
March1st to 15thDay
28%2416%29%17%
1818
16th to endDay
23%27%19%25%21%
2146
April1st to 15thDay
22%37%14%24%28%
2150
16th to endDay
19%26%16%27%26%
2160
May1st to 15thDay
28%38%15%23%20%
2293
16th to endDay
27%5%8%17%24%16%
2434
June1st to 15thDay
17%410%26%27%12%
2340
16th to endDay
23%6%10%25%20%13%
2340
July1st to 15thDay
30%6%14%27%17%4
2201
16th to endDay
20%5%17%34%19%2
2251
August1st to 15thDay
18%5%15%29%26%4
2147
16th to endDay
32%7%14%25%16%4
2292
September1st to 15thDay
34%5%11%23%20%5%
2064
16th to endDay
31%37%20%26%10%
1837
October1st to 15thDay
25%38%23%24%14%
1815
16th to endDay
17%1315%37%23%
1782
November1st to 15thDay
19%26%22%29%19%
1583
16th to endDay
22%1416%30%24%
1620
December1st to 15thDay
28%15%21%31%12%
1620
16th to endDay
28%2422%30%11%
1728
January1st to 15thNight
24%2417%30%19%
2324
16th to endNight
22%1416%28%25%
2304
February1st to 15thNight
24%26%15%24%26%
2112
16th to endNight
24%2414%27%26%
1894
March1st to 15thNight
27%26%16%24%22%
2142
16th to endNight
22%38%21%25%18%
2075
April1st to 15thNight
21%49%17%23%23%
1798
16th to endNight
17%39%18%26%23%
1800
May1st to 15thNight
21%412%18%22%20%
1656
16th to endNight
20%7%13%20%22%15%
1685
June1st to 15thNight
15%5%12%28%25%11%
1620
16th to endNight
14%5%16%28%22%12%
1620
July1st to 15thNight
24%5%14%31%20%4
1530
16th to endNight
15%5%17%31%27%3
1651
August1st to 15thNight
18%412%27%28%8%
1789
16th to endNight
21%6%15%28%22%5%
1910
September1st to 15thNight
28%412%25%20%8%
1894
16th to endNight
28%5%8%21%24%12%
1848
October1st to 15thNight
19%312%26%22%15%
1815
16th to endNight
15%2417%33%26%
2073
November1st to 15thNight
16%36%24%26%22%
2275
16th to endNight
22%3411%30%27%
2340
December1st to 15thNight
25%25%19%28%18%
2340
16th to endNight
26%35%19%29%16%
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
21%422%41%10%1
90
16th to endDay
7%8%35%31%14%3
96
February1st to 15thDay
4230%34%26%2
90
16th to endDay
38%41%32%13%
81
March1st to 15thDay
12%143%30%13%
90
16th to endDay
10%35%39%10%3
130
April1st to 15thDay
8%13%44%25%7%
269
16th to endDay
318%41%24%10%2
270
May1st to 15thDay
9%6%40%32%8%1
430
16th to endDay
9%435%35%14%1
517
June1st to 15thDay
3121%46%23%3
495
16th to endDay
3113%39%32%8%
495
July1st to 15thDay
6%6%40%38%6%
475
16th to endDay
2332%44%16%
450
August1st to 15thDay
3227%47%18%
315
16th to endDay
6%16%31%39%14%
332
September1st to 15thDay
5%331%41%16%
219
16th to endDay
10%16%22%40%18%
96
October1st to 15thDay
4213%40%34%5%
90
16th to endDay
11%216%35%27%7%
96
November1st to 15thDay
20%417%35%14%7%
90
16th to endDay
14%17%25%27%7%6%
90
December1st to 15thDay
18%5%25%30%20%
90
16th to endDay
7%14%38%33%6%
96
January1st to 15thNight
10%435%37%11%
897
16th to endNight
7%7%37%36%9%
768
February1st to 15thNight
9%7%37%36%9%
704
16th to endNight
8%9%50%25%4
632
March1st to 15thNight
9%9%40%34%4
702
16th to endNight
7%12%47%27%5%
576
April1st to 15thNight
6%9%54%25%3
539
16th to endNight
38%52%31%3
540
May1st to 15thNight
5%7%50%31%6%
540
16th to endNight
4438%39%12%
563
June1st to 15thNight
2134%50%11%
540
16th to endNight
222%55%18%
540
July1st to 15thNight
6%7%54%30%
510
16th to endNight
2353%37%2
564
August1st to 15thNight
2339%51%2
539
16th to endNight
35%39%46%3
573
September1st to 15thNight
8%6%43%37%2
540
16th to endNight
8%11%51%26%
501
October1st to 15thNight
7%127%42%20%
495
16th to endNight
36%28%41%19%2
665
November1st to 15thNight
4432%39%17%1
875
16th to endNight
8%5%33%36%15%1
900
December1st to 15thNight
12%5%33%35%11%
900
16th to endNight
9%8%35%36%9%
960
Page generated at 2017-09-19 06:32:29. Version ac04

Copyright 2017 A. Danko


Big Spring State Park Clear Sky Chart | Charts Home