Martin Dies, Jr. State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Martin Dies, Jr. State Park clear sky chart from 2005-11-05 to 2017-09-17.

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
50%
15423
23%
46876
17%
15376
56%
15376
30%
28354

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
32%
900
23%
2327
10%
895
40%
895
26%
1558
January16th to endNight
30%
960
25%
2496
9%
960
39%
960
27%
1662
February1st to 15thNight
30%
862
24%
2270
8%
858
39%
858
27%
1481
February16th to endNight
25%
474
26%
1736
11%
474
41%
474
20%
1058
March1st to 15thNight
30%
540
24%
1980
14%
540
42%
540
21%
1218
March16th to endNight
39%
576
21%
2112
16%
576
47%
576
26%
1230
April1st to 15thNight
34%
539
22%
1884
13%
539
47%
539
25%
1104
April16th to endNight
39%
540
22%
1800
17%
540
49%
540
26%
1088
May1st to 15thNight
39%
539
18%
1770
13%
539
48%
539
26%
1094
May16th to endNight
58%
563
25%
1684
22%
561
65%
561
39%
953
June1st to 15thNight
76%
540
19%
1620
19%
540
81%
540
42%
883
June16th to endNight
72%
540
18%
1620
19%
540
75%
540
34%
972
July1st to 15thNight
79%
510
17%
1530
20%
510
80%
510
38%
894
July16th to endNight
81%
564
16%
1594
20%
531
81%
531
37%
932
August1st to 15thNight
87%
539
25%
1654
28%
536
88%
536
49%
830
August16th to endNight
70%
573
14%
1910
17%
573
70%
573
24%
1240
September1st to 15thNight
71%
540
18%
1882
19%
540
72%
540
29%
1092
September16th to endNight
69%
498
28%
1837
31%
498
71%
498
29%
1034
October1st to 15thNight
68%
652
31%
1972
25%
652
71%
652
40%
1064
October16th to endNight
58%
704
35%
2112
24%
704
65%
704
42%
1116
November1st to 15thNight
51%
700
28%
2100
20%
700
56%
700
34%
1219
November16th to endNight
44%
720
31%
2160
20%
720
53%
720
33%
1254
December1st to 15thNight
37%
890
24%
2330
12%
890
44%
890
24%
1623
December16th to endNight
31%
960
19%
2496
8%
960
37%
960
22%
1755

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
13%5%25%5%35%5%5%7%39%
47893
Night
12%5%2442345%7%47%
47072
TransparencyDay
43%6%10%17%16%6%
47593
Night
35%5%12%19%18%8%
46877
SeeingDay
12%417%25%27%12%
5462
Night
15%6%22%31%20%3
15424

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
20%6%23413235%44%
1611
16th to endDay
20%6%23323345%43%
1728
February1st to 15thDay
17%7%345%3423443%
1599
16th to endDay
19%7%35%414335%40%
1738
March1st to 15thDay
23%7%35%413235%38%
1980
16th to endDay
16%6%35%5%24445%41%
2110
April1st to 15thDay
14%6%35%5%345%5%5%40%
2064
16th to endDay
13%5%36%6%36%46%6%37%
2160
May1st to 15thDay
13%7%37%6%45%5%5%7%34%
2178
16th to endDay
9%435%6%47%6%7%9%35%
2430
June1st to 15thDay
6%426%7%48%6%7%10%33%
2340
16th to endDay
8%426%8%5%9%7%8%10%27%
2340
July1st to 15thDay
10%425%8%5%8%7%7%10%29%
2340
16th to endDay
7%5%37%7%48%8%7%8%29%
2466
August1st to 15thDay
4325%6%47%6%8%11%38%
2295
16th to endDay
10%5%27%7%5%8%7%6%8%31%
2292
September1st to 15thDay
12%425%6%46%6%5%7%38%
2074
16th to endDay
9%326%7%45%5%7%7%42%
1823
October1st to 15thDay
10%324434347%51%
1650
16th to endDay
12%313323335%58%
1760
November1st to 15thDay
9%5%27%5%24346%47%
1758
16th to endDay
14%5%25%42333450%
1800
December1st to 15thDay
18%9%35%42334439%
1629
16th to endDay
19%10%45%5%23335%35%
1728
January1st to 15thNight
18%8%25%313335%44%
2327
16th to endNight
21%8%23212235%45%
2496
February1st to 15thNight
16%7%23422336%46%
2260
16th to endNight
16%7%25%32433445%
1736
March1st to 15thNight
20%6%25%323336%44%
1980
16th to endNight
11%6%34423347%48%
2112
April1st to 15thNight
11%424325%45%8%45%
1884
16th to endNight
12%5%2443435%8%45%
1800
May1st to 15thNight
11%5%34425%46%9%42%
1769
16th to endNight
8%41332336%10%50%
1683
June1st to 15thNight
331332446%10%56%
1620
16th to endNight
5%313425%6%7%11%46%
1620
July1st to 15thNight
7%3124145%7%13%47%
1620
16th to endNight
32245%25%5%8%12%46%
1702
August1st to 15thNight
311221347%13%58%
1664
16th to endNight
8%5%25%5%35%5%7%11%37%
1910
September1st to 15thNight
9%425%42447%8%46%
1882
16th to endNight
8%5%3343445%7%50%
1837
October1st to 15thNight
6%2233245%5%6%58%
1972
16th to endNight
10%31232233461%
2112
November1st to 15thNight
9%42442435%6%51%
2100
16th to endNight
14%5%13322235%54%
2160
December1st to 15thNight
18%8%25%413345%40%
2330
16th to endNight
18%9%34424345%38%
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
43%3415%22%10%
1612
16th to endDay
43%35%14%20%11%
1728
February1st to 15thDay
45%25%15%20%10%
1600
16th to endDay
47%36%13%19%9%
1738
March1st to 15thDay
49%37%12%20%6%
1980
16th to endDay
43%47%14%22%5%
2112
April1st to 15thDay
45%46%16%17%8%
2064
16th to endDay
44%7%9%14%17%6%
2160
May1st to 15thDay
48%6%9%14%14%6%
2178
16th to endDay
42%7%13%20%13%1
2434
June1st to 15thDay
43%9%12%18%15%
2340
16th to endDay
47%9%16%17%8%
2340
July1st to 15thDay
44%10%17%19%8%
2201
16th to endDay
45%11%17%19%5%
2311
August1st to 15thDay
35%9%19%26%8%
2281
16th to endDay
47%11%16%16%6%1
2292
September1st to 15thDay
43%7%15%16%12%5%
2074
16th to endDay
39%7%9%18%17%7%
1823
October1st to 15thDay
33%48%19%17%15%
1650
16th to endDay
29%3414%32%15%
1760
November1st to 15thDay
37%48%18%21%9%
1758
16th to endDay
38%45%12%26%13%
1800
December1st to 15thDay
48%47%17%16%6%
1629
16th to endDay
50%36%17%16%6%
1728
January1st to 15thNight
43%25%15%20%12%
2327
16th to endNight
43%3415%20%12%
2496
February1st to 15thNight
41%26%16%20%12%
2270
16th to endNight
42%45%15%19%12%
1736
March1st to 15thNight
43%38%14%19%10%
1980
16th to endNight
36%5%12%15%22%7%
2112
April1st to 15thNight
36%5%10%20%15%11%
1884
16th to endNight
36%6%10%19%17%9%
1800
May1st to 15thNight
37%7%13%16%16%8%
1770
16th to endNight
28%5%17%27%17%2
1685
June1st to 15thNight
23%7%15%32%18%1
1620
16th to endNight
28%11%20%26%12%
1620
July1st to 15thNight
25%10%29%25%9%
1530
16th to endNight
26%10%31%24%6%
1594
August1st to 15thNight
16%9%28%33%12%
1654
16th to endNight
38%10%24%17%6%2
1910
September1st to 15thNight
33%7%20%19%12%5%
1882
16th to endNight
33%5%11%19%19%9%
1837
October1st to 15thNight
25%5%9%22%19%16%
1972
16th to endNight
27%25%14%30%19%
2112
November1st to 15thNight
32%411%19%23%8%
2100
16th to endNight
34%37%11%27%15%
2160
December1st to 15thNight
45%46%19%15%8%
2330
16th to endNight
47%46%14%18%8%
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
31%7%37%15%7%
90
16th to endDay
19%22%36%15%5%
96
February1st to 15thDay
8%20%41%27%2
90
16th to endDay
20%22%34%19%2
81
March1st to 15thDay
30%16%38%5%8%
90
16th to endDay
19%11%31%26%10%1
96
April1st to 15thDay
15%10%34%23%13%1
183
16th to endDay
23%7%24%28%12%3
270
May1st to 15thDay
20%5%28%29%13%2
315
16th to endDay
10%426%33%20%4
517
June1st to 15thDay
8%13%35%32%9%
495
16th to endDay
9%111%29%33%15%
495
July1st to 15thDay
8%18%28%36%18%
475
16th to endDay
6%5%20%43%25%
515
August1st to 15thDay
8%216%48%23%
448
16th to endDay
15%1315%35%27%
332
September1st to 15thDay
46%24%40%23%
229
16th to endDay
7%26%26%44%12%
93
October1st to 15thDay
22%47%16%13%
90
16th to endDay
19%318%16%31%10%
96
November1st to 15thDay
10%5%41%27%14%1
90
16th to endDay
24%7%34%23%5%4
90
December1st to 15thDay
26%7%31%22%5%6%
90
16th to endDay
29%20%28%19%11
96
January1st to 15thNight
23%12%26%28%8%
900
16th to endNight
25%11%30%28%4
960
February1st to 15thNight
22%12%31%28%5%
862
16th to endNight
20%13%38%25%2
474
March1st to 15thNight
26%8%31%27%5%
540
16th to endNight
14%8%34%30%10%
576
April1st to 15thNight
14%8%39%28%9%
539
16th to endNight
15%6%33%32%11%
540
May1st to 15thNight
16%435%32%10%1
540
16th to endNight
9%224%39%21%2
563
June1st to 15thNight
410%45%33%5%
540
16th to endNight
5%12%35%38%7%
540
July1st to 15thNight
5%440%39%10%
510
16th to endNight
3328%54%8%
564
August1st to 15thNight
3335%47%10%
539
16th to endNight
10%1428%43%11%
573
September1st to 15thNight
10%17%29%40%11%
540
16th to endNight
12%19%29%38%9%
498
October1st to 15thNight
7%214%36%33%4
652
16th to endNight
12%421%33%25%2
704
November1st to 15thNight
10%7%26%33%20%1
700
16th to endNight
17%7%27%32%13%
720
December1st to 15thNight
24%7%25%29%11%
890
16th to endNight
24%11%29%28%6%
960
Page generated at 2017-09-18 07:38:25. Version ac04

Copyright 2017 A. Danko


Martin Dies, Jr. State Park Clear Sky Chart | Charts Home