Monahans Sandhills State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Monahans Sandhills 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
57%
15511
33%
47013
22%
15468
67%
15468
48%
23519

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
53%
800
35%
2231
20%
799
64%
799
47%
1176
January16th to endNight
52%
768
40%
2304
25%
768
65%
768
48%
1138
February1st to 15thNight
50%
702
34%
2107
20%
698
64%
698
50%
1031
February16th to endNight
39%
632
34%
1894
16%
632
55%
632
46%
956
March1st to 15thNight
44%
720
32%
2160
17%
720
58%
720
43%
1114
March16th to endNight
37%
606
36%
2012
18%
606
57%
606
48%
926
April1st to 15thNight
33%
539
33%
1798
16%
539
54%
539
42%
882
April16th to endNight
36%
540
36%
1800
20%
540
60%
540
51%
794
May1st to 15thNight
40%
540
28%
1748
21%
539
56%
539
47%
831
May16th to endNight
47%
562
25%
1684
19%
561
59%
561
40%
930
June1st to 15thNight
56%
540
26%
1620
19%
540
66%
540
56%
751
June16th to endNight
67%
540
27%
1620
23%
540
73%
540
53%
777
July1st to 15thNight
81%
510
24%
1530
25%
510
83%
510
49%
775
July16th to endNight
84%
564
28%
1771
33%
531
87%
531
47%
848
August1st to 15thNight
86%
539
30%
1789
38%
536
87%
536
49%
841
August16th to endNight
83%
573
27%
1910
33%
573
84%
573
43%
978
September1st to 15thNight
76%
540
23%
1848
26%
540
78%
540
35%
1015
September16th to endNight
72%
501
31%
1848
32%
501
76%
501
35%
960
October1st to 15thNight
60%
495
36%
1815
33%
495
66%
495
43%
827
October16th to endNight
67%
668
39%
2076
26%
668
75%
668
59%
918
November1st to 15thNight
61%
872
37%
2272
18%
872
70%
872
59%
1148
November16th to endNight
58%
900
37%
2340
18%
900
67%
900
53%
1247
December1st to 15thNight
55%
900
37%
2340
19%
900
65%
900
49%
1281
December16th to endNight
50%
960
35%
2496
19%
960
59%
960
49%
1375

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
5%313323346%62%
47758
Night
4212323347%62%
47228
Cloud CoverDay
5%313323346%62%
47756
Night
5%212323347%63%
47228
TransparencyDay
21%48%18%26%19%
47469
Night
20%49%19%25%21%
47020
SeeingDay
5%318%36%27%8%
5412
Night
5%329%43%16%
15518

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
7%424422237%59%
1717
16th to endDay
7%313323345%63%
1920
February1st to 15thDay
221331235%6%66%
1750
16th to endDay
5%41321234465%
1580
March1st to 15thDay
6%313324447%57%
1800
16th to endDay
5%312213246%66%
2206
April1st to 15thDay
4212223437%66%
2150
16th to endDay
2112112335%74%
2160
May1st to 15thDay
5%213312247%64%
2199
16th to endDay
5%21221335%6%64%
2430
June1st to 15thDay
111111335%6%71%
2340
16th to endDay
421332445%7%60%
2340
July1st to 15thDay
5%21443446%9%53%
2337
16th to endDay
4213335%5%6%8%55%
2277
August1st to 15thDay
211232437%10%59%
2160
16th to endDay
43145%35%5%7%9%48%
2292
September1st to 15thDay
9%3145%245%5%8%48%
2112
16th to endDay
7%41342445%6%54%
1837
October1st to 15thDay
6%323213245%65%
1815
16th to endDay
321221222374%
1785
November1st to 15thDay
4311112245%70%
1583
16th to endDay
6%31221223468%
1620
December1st to 15thDay
5%5%2332335%6%57%
1620
16th to endDay
5%5%12314436%60%
1728
January1st to 15thNight
5%313413337%61%
2231
16th to endNight
7%212212336%64%
2304
February1st to 15thNight
5%213213336%65%
2102
16th to endNight
5%212323345%64%
1894
March1st to 15thNight
5%412313346%61%
2160
16th to endNight
3312213246%67%
2012
April1st to 15thNight
4312314347%62%
1798
16th to endNight
2212213235%71%
1800
May1st to 15thNight
5%212222347%64%
1748
16th to endNight
5%3133245%5%7%57%
1683
June1st to 15thNight
211131336%8%66%
1620
16th to endNight
1122235%7%11%61%
1620
July1st to 15thNight
22134145%6%10%58%
1620
16th to endNight
32232446%11%58%
1891
August1st to 15thNight
311242347%11%58%
1800
16th to endNight
31134246%8%12%51%
1910
September1st to 15thNight
6%3134346%6%10%48%
1848
16th to endNight
6%3144145%6%9%51%
1848
October1st to 15thNight
6%212222346%65%
1815
16th to endNight
32122223475%
2076
November1st to 15thNight
422212235%71%
2272
16th to endNight
5%21321333467%
2340
December1st to 15thNight
6%312223445%62%
2340
16th to endNight
6%313213445%61%
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
8%324413236%59%
1717
16th to endDay
7%31331333464%
1920
February1st to 15thDay
231321235%7%66%
1750
16th to endDay
5%413212336%64%
1580
March1st to 15thDay
6%21332445%6%58%
1800
16th to endDay
5%312223236%66%
2204
April1st to 15thDay
4212213346%66%
2150
16th to endDay
212112245%74%
2160
May1st to 15thDay
6%213312246%64%
2199
16th to endDay
5%21222335%6%64%
2430
June1st to 15thDay
111213347%71%
2340
16th to endDay
4212324447%60%
2340
July1st to 15thDay
5%223335%46%9%53%
2337
16th to endDay
42133245%6%8%56%
2277
August1st to 15thDay
21123245%6%10%58%
2160
16th to endDay
5%3245%36%5%7%8%48%
2292
September1st to 15thDay
9%42442445%7%48%
2112
16th to endDay
8%41342345%7%54%
1837
October1st to 15thDay
7%312313335%65%
1815
16th to endDay
32221222375%
1785
November1st to 15thDay
4212212235%70%
1583
16th to endDay
6%31221222468%
1620
December1st to 15thDay
6%5%1322335%6%57%
1620
16th to endDay
6%412314446%60%
1728
January1st to 15thNight
5%313422336%62%
2231
16th to endNight
7%212213336%64%
2304
February1st to 15thNight
5%212213436%65%
2102
16th to endNight
6%212323335%65%
1894
March1st to 15thNight
6%223223346%61%
2160
16th to endNight
4212213235%68%
2012
April1st to 15thNight
5%313224346%63%
1798
16th to endNight
3212213335%72%
1800
May1st to 15thNight
6%21231235%6%64%
1748
16th to endNight
5%2233245%5%6%58%
1683
June1st to 15thNight
21122345%9%66%
1620
16th to endNight
11232446%11%61%
1620
July1st to 15thNight
221233445%11%57%
1620
16th to endNight
41232445%11%58%
1891
August1st to 15thNight
3124335%7%10%58%
1800
16th to endNight
22134246%8%12%51%
1910
September1st to 15thNight
7%3143345%7%10%49%
1848
16th to endNight
6%3134245%6%9%52%
1848
October1st to 15thNight
6%212223245%65%
1815
16th to endNight
32221123375%
2076
November1st to 15thNight
323212235%71%
2272
16th to endNight
5%21322233468%
2340
December1st to 15thNight
7%312313345%62%
2340
16th to endNight
6%313222445%62%
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
28%1422%27%16%
1718
16th to endDay
24%2415%33%19%
1920
February1st to 15thDay
17%37%16%24%29%
1751
16th to endDay
21%2414%29%28%
1580
March1st to 15thDay
25%35%13%29%23%
1800
16th to endDay
19%25%16%24%30%
2206
April1st to 15thDay
19%36%10%25%34%
2150
16th to endDay
13%26%13%28%35%
2160
May1st to 15thDay
21%36%14%24%30%
2199
16th to endDay
19%48%17%23%26%
2434
June1st to 15thDay
12%5%9%19%31%22%
2340
16th to endDay
22%5%11%21%22%17%
2340
July1st to 15thDay
25%5%14%28%19%6%
2198
16th to endDay
21%7%14%29%21%4
2134
August1st to 15thDay
17%7%13%29%25%6%
2147
16th to endDay
29%9%16%21%18%4
2292
September1st to 15thDay
31%7%14%21%20%6%
2112
16th to endDay
29%5%8%19%28%9%
1837
October1st to 15thDay
22%39%22%22%19%
1815
16th to endDay
16%2413%34%28%
1785
November1st to 15thDay
16%37%19%30%22%
1583
16th to endDay
22%15%13%29%27%
1620
December1st to 15thDay
27%36%18%29%14%
1620
16th to endDay
24%46%19%33%12%
1728
January1st to 15thNight
24%25%15%31%20%
2231
16th to endNight
21%2415%28%27%
2304
February1st to 15thNight
20%37%13%24%31%
2112
16th to endNight
22%25%10%28%30%
1894
March1st to 15thNight
24%36%15%23%26%
2160
16th to endNight
19%36%20%22%28%
2012
April1st to 15thNight
22%48%13%21%29%
1798
16th to endNight
15%47%18%22%32%
1800
May1st to 15thNight
20%49%17%22%26%
1749
16th to endNight
24%8%11%17%18%19%
1685
June1st to 15thNight
14%5%12%23%29%14%
1620
16th to endNight
15%6%15%24%22%15%
1620
July1st to 15thNight
18%6%16%31%20%5%
1530
16th to endNight
17%7%16%29%24%4
1771
August1st to 15thNight
18%5%12%29%26%7%
1789
16th to endNight
20%8%17%27%19%6%
1910
September1st to 15thNight
27%7%15%24%18%6%
1848
16th to endNight
27%5%9%21%22%13%
1848
October1st to 15thNight
21%410%22%21%20%
1815
16th to endNight
14%26%13%30%32%
2076
November1st to 15thNight
16%35%21%28%25%
2272
16th to endNight
21%2410%26%33%
2340
December1st to 15thNight
23%35%19%27%21%
2340
16th to endNight
23%36%17%30%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
12%325%27%24%6%
90
16th to endDay
11%8%27%31%15%6%
96
February1st to 15thDay
4317%35%31%7%
90
16th to endDay
11%7%23%38%17%2
81
March1st to 15thDay
6%223%44%21%2
90
16th to endDay
39%27%39%16%4
222
April1st to 15thDay
7%10%36%33%12%
269
16th to endDay
211%40%31%13%
270
May1st to 15thDay
49%40%33%11%
336
16th to endDay
7%329%43%14%1
517
June1st to 15thDay
116%49%26%5%
495
16th to endDay
313%41%32%9%
495
July1st to 15thDay
6%439%40%9%
472
16th to endDay
2336%40%17%
327
August1st to 15thDay
3126%46%21%
315
16th to endDay
6%15%33%37%16%
332
September1st to 15thDay
6%432%43%12%
267
16th to endDay
9%8%26%45%10%
96
October1st to 15thDay
15%114%11%45%12%
90
16th to endDay
36%9%26%33%21%
96
November1st to 15thDay
16%314%31%25%8%
90
16th to endDay
20%7%18%30%15%7%
90
December1st to 15thDay
10%5%20%36%24%3
90
16th to endDay
7%5%33%43%9%1
96
January1st to 15thNight
7%330%44%13%
804
16th to endNight
7%431%43%12%
768
February1st to 15thNight
6%5%35%39%12%
704
16th to endNight
6%7%43%37%4
632
March1st to 15thNight
8%7%37%39%7%
720
16th to endNight
38%48%31%6%
606
April1st to 15thNight
5%9%50%30%3
539
16th to endNight
36%51%34%3
540
May1st to 15thNight
6%6%45%37%5%
540
16th to endNight
6%338%44%6%
563
June1st to 15thNight
2138%49%8%
540
16th to endNight
2125%53%15%1
540
July1st to 15thNight
39%59%26%1
510
16th to endNight
26%59%30%1
564
August1st to 15thNight
2346%44%1
539
16th to endNight
36%43%43%2
573
September1st to 15thNight
7%8%48%32%2
540
16th to endNight
7%14%51%25%
501
October1st to 15thNight
7%226%46%15%
495
16th to endNight
4223%47%19%2
668
November1st to 15thNight
5%227%42%21%
872
16th to endNight
7%327%40%20%
900
December1st to 15thNight
8%329%44%13%
900
16th to endNight
8%5%33%39%13%1
960
Page generated at 2017-09-19 06:32:31. Version ac04

Copyright 2017 A. Danko


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