Mission Tejas State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mission Tejas State Park clear sky chart from 2005-11-05 to 2017-09-21.

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
48%
15501
26%
46942
17%
15454
56%
15454
33%
27221

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
33%
900
26%
2327
10%
895
43%
895
29%
1493
January16th to endNight
28%
960
27%
2496
9%
960
39%
960
29%
1615
February1st to 15thNight
28%
821
24%
2227
8%
817
38%
817
28%
1412
February16th to endNight
24%
533
28%
1795
11%
533
40%
533
25%
1053
March1st to 15thNight
27%
540
26%
1980
13%
540
42%
540
22%
1185
March16th to endNight
33%
576
21%
2112
14%
576
43%
576
26%
1206
April1st to 15thNight
31%
539
24%
1921
13%
539
47%
539
28%
1055
April16th to endNight
34%
540
23%
1800
13%
540
48%
540
29%
1039
May1st to 15thNight
33%
539
20%
1674
14%
539
43%
539
29%
1017
May16th to endNight
54%
563
26%
1684
21%
561
65%
561
39%
939
June1st to 15thNight
73%
540
21%
1620
21%
540
78%
540
47%
823
June16th to endNight
74%
540
23%
1620
25%
540
78%
540
42%
874
July1st to 15thNight
75%
510
21%
1530
23%
510
79%
510
43%
835
July16th to endNight
82%
564
20%
1594
23%
531
84%
531
43%
867
August1st to 15thNight
86%
539
29%
1610
34%
536
86%
536
54%
764
August16th to endNight
72%
573
19%
1891
22%
573
73%
573
27%
1170
September1st to 15thNight
71%
540
20%
1962
24%
540
73%
540
31%
1080
September16th to endNight
71%
510
31%
1881
32%
510
74%
510
35%
981
October1st to 15thNight
65%
618
33%
1938
26%
618
70%
618
40%
1027
October16th to endNight
56%
704
36%
2112
23%
704
65%
704
46%
1079
November1st to 15thNight
49%
700
29%
2100
20%
700
57%
700
36%
1193
November16th to endNight
42%
792
32%
2232
18%
792
52%
792
35%
1316
December1st to 15thNight
36%
900
27%
2340
13%
900
44%
900
30%
1518
December16th to endNight
31%
960
23%
2496
10%
960
39%
960
26%
1680

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
12%5%25%5%35%45%7%42%
47915
Night
10%424323447%51%
47140
TransparencyDay
40%410%19%18%6%
47615
Night
33%411%21%19%9%
46945
SeeingDay
11%5%18%28%27%7%
5515
Night
14%7%25%31%18%2
15502

By Month

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
15%7%3432323448%
1611
16th to endDay
19%6%14312336%47%
1728
February1st to 15thDay
16%7%35%42222446%
1645
16th to endDay
18%6%3441333445%
1679
March1st to 15thDay
21%6%25%323245%40%
1980
16th to endDay
16%7%25%424345%42%
2110
April1st to 15thDay
12%6%35%33445%8%42%
2025
16th to endDay
12%5%34435%5%5%6%41%
2160
May1st to 15thDay
13%6%36%5%35%5%5%7%36%
2275
16th to endDay
8%5%35%6%46%6%6%9%38%
2430
June1st to 15thDay
4425%6%46%7%7%10%38%
2340
16th to endDay
6%426%6%47%6%7%11%34%
2340
July1st to 15thDay
8%435%7%47%6%6%10%35%
2340
16th to endDay
7%426%6%5%7%7%8%9%33%
2466
August1st to 15thDay
5%2135%45%5%7%9%49%
2340
16th to endDay
8%5%36%8%5%6%6%7%9%33%
2309
September1st to 15thDay
9%5%245%36%5%6%8%41%
1995
16th to endDay
8%3245%35%46%8%47%
1871
October1st to 15thDay
10%423424346%53%
1680
16th to endDay
12%31221223462%
1760
November1st to 15thDay
12%5%2332445%7%47%
1758
16th to endDay
15%5%2432333450%
1725
December1st to 15thDay
19%8%24423235%43%
1620
16th to endDay
18%9%35%423445%37%
1728
January1st to 15thNight
16%6%13313436%48%
2327
16th to endNight
17%6%2431333449%
2496
February1st to 15thNight
14%7%33313235%49%
2219
16th to endNight
17%424313345%49%
1795
March1st to 15thNight
17%6%34422335%45%
1980
16th to endNight
13%5%25%413336%49%
2112
April1st to 15thNight
7%42443445%6%51%
1921
16th to endNight
11%324424347%49%
1800
May1st to 15thNight
9%5%35%43346%9%45%
1673
16th to endNight
6%21342446%11%51%
1683
June1st to 15thNight
31133233410%61%
1620
16th to endNight
3213325%5%7%11%53%
1620
July1st to 15thNight
5%32332446%10%54%
1620
16th to endNight
3212325%6%6%13%50%
1702
August1st to 15thNight
3212125%7%12%60%
1620
16th to endNight
7%3246%35%6%8%12%39%
1891
September1st to 15thNight
8%42343446%8%50%
1962
16th to endNight
6%42432435%7%55%
1881
October1st to 15thNight
8%313313345%60%
1938
16th to endNight
12%2221223465%
2112
November1st to 15thNight
10%414313436%56%
2100
16th to endNight
14%5%1331333454%
2232
December1st to 15thNight
15%6%24313436%46%
2340
16th to endNight
16%8%25%423335%44%
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
41%25%15%25%10%
1612
16th to endDay
40%15%17%22%11%
1728
February1st to 15thDay
44%1416%21%10%
1646
16th to endDay
44%25%14%20%12%
1679
March1st to 15thDay
47%36%15%20%6%
1980
16th to endDay
44%37%14%24%4
2112
April1st to 15thDay
40%48%19%17%8%
2025
16th to endDay
42%410%15%20%6%
2160
May1st to 15thDay
46%5%11%15%15%6%
2275
16th to endDay
41%6%12%20%17%1
2434
June1st to 15thDay
37%6%12%24%16%1
2340
16th to endDay
41%8%13%22%12%2
2340
July1st to 15thDay
40%8%17%23%10%
2201
16th to endDay
41%8%18%21%9%
2311
August1st to 15thDay
28%6%17%31%13%
2326
16th to endDay
45%8%14%21%7%2
2309
September1st to 15thDay
39%5%13%20%13%7%
1995
16th to endDay
34%5%9%20%20%9%
1871
October1st to 15thDay
33%39%18%18%16%
1680
16th to endDay
26%2415%35%15%
1760
November1st to 15thDay
36%38%23%20%8%
1758
16th to endDay
38%2414%27%12%
1725
December1st to 15thDay
46%27%17%19%7%
1620
16th to endDay
49%36%16%17%6%
1728
January1st to 15thNight
39%25%16%22%13%
2327
16th to endNight
40%25%14%23%13%
2496
February1st to 15thNight
38%35%16%19%15%
2229
16th to endNight
38%37%16%18%14%
1795
March1st to 15thNight
43%27%16%20%9%
1980
16th to endNight
37%311%16%22%8%
2112
April1st to 15thNight
33%410%23%17%11%
1921
16th to endNight
35%311%19%18%10%
1800
May1st to 15thNight
36%5%13%17%18%7%
1674
16th to endNight
27%5%18%28%17%2
1685
June1st to 15thNight
20%5%15%32%22%1
1620
16th to endNight
24%6%18%29%19%2
1620
July1st to 15thNight
25%5%23%31%13%
1530
16th to endNight
23%7%28%29%10%
1594
August1st to 15thNight
15%5%23%34%18%1
1610
16th to endNight
35%9%20%24%7%2
1891
September1st to 15thNight
32%417%23%14%7%
1962
16th to endNight
29%410%21%23%10%
1881
October1st to 15thNight
26%48%22%19%18%
1938
16th to endNight
24%15%17%30%20%
2112
November1st to 15thNight
31%39%21%24%9%
2100
16th to endNight
33%26%14%26%16%
2232
December1st to 15thNight
39%39%20%18%8%
2340
16th to endNight
44%26%17%18%10%
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
23%13%37%20%5%
90
16th to endDay
20%21%36%10%9%1
96
February1st to 15thDay
13%26%37%17%4
90
16th to endDay
18%27%34%13%6%
81
March1st to 15thDay
26%21%36%12%3
90
16th to endDay
17%16%28%28%8%1
96
April1st to 15thDay
20%9%36%16%14%2
144
16th to endDay
17%8%32%30%10%1
270
May1st to 15thDay
16%9%35%26%9%1
412
16th to endDay
13%7%28%30%17%2
517
June1st to 15thDay
5%114%42%28%7%
495
16th to endDay
8%110%36%31%12%
495
July1st to 15thDay
6%12%34%36%9%
475
16th to endDay
46%26%46%15%
515
August1st to 15thDay
6%329%46%13%
493
16th to endDay
16%6%18%42%14%
349
September1st to 15thDay
7%29%39%22%
150
16th to endDay
38%28%40%19%
105
October1st to 15thDay
121%48%21%7%
90
16th to endDay
17%6%15%19%33%7%
96
November1st to 15thDay
21%237%24%14%
90
16th to endDay
23%12%27%25%6%4
90
December1st to 15thDay
26%10%25%23%10%4
90
16th to endDay
29%21%30%14%4
96
January1st to 15thNight
22%13%28%27%8%
900
16th to endNight
21%13%33%27%4
960
February1st to 15thNight
20%14%34%26%4
821
16th to endNight
22%11%39%23%3
533
March1st to 15thNight
21%11%36%23%6%
540
16th to endNight
14%11%37%28%7%
576
April1st to 15thNight
9%13%41%25%9%
539
16th to endNight
14%8%39%25%10%
540
May1st to 15thNight
11%9%41%28%7%1
540
16th to endNight
8%330%37%18%2
563
June1st to 15thNight
413%47%31%2
540
16th to endNight
411%46%30%6%
540
July1st to 15thNight
5%8%47%31%7%
510
16th to endNight
4434%47%6%
564
August1st to 15thNight
4440%43%6%
539
16th to endNight
9%6%36%39%7%
573
September1st to 15thNight
10%8%32%40%7%
540
16th to endNight
7%111%30%41%6%
510
October1st to 15thNight
9%316%36%28%5%
618
16th to endNight
13%5%22%32%23%2
704
November1st to 15thNight
13%5%27%33%19%1
700
16th to endNight
17%8%29%28%15%
792
December1st to 15thNight
21%8%29%30%9%
900
16th to endNight
24%11%28%27%7%
960
Page generated at 2017-09-22 06:35:29. Version ac04

Copyright 2017 A. Danko


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