Guadalupe River State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Guadalupe River State Park clear sky chart from 2005-11-05 to 2017-09-22.

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
49%
15420
26%
47015
18%
15374
57%
15374
33%
27329

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
38%
898
26%
2327
11%
895
47%
895
32%
1477
January16th to endNight
36%
861
30%
2397
13%
861
48%
861
31%
1469
February1st to 15thNight
35%
704
28%
2106
13%
698
47%
698
29%
1233
February16th to endNight
24%
632
28%
1894
8%
632
41%
632
29%
1093
March1st to 15thNight
32%
570
28%
2010
13%
570
48%
570
26%
1168
March16th to endNight
30%
576
23%
2112
15%
576
42%
576
25%
1223
April1st to 15thNight
27%
539
23%
1977
12%
539
44%
539
25%
1138
April16th to endNight
27%
540
25%
1764
14%
540
44%
540
25%
1114
May1st to 15thNight
31%
539
22%
1620
15%
539
42%
539
29%
998
May16th to endNight
43%
562
24%
1684
18%
561
54%
561
30%
1027
June1st to 15thNight
62%
540
23%
1620
21%
540
69%
540
48%
828
June16th to endNight
63%
540
21%
1620
21%
540
68%
540
37%
927
July1st to 15thNight
75%
510
20%
1530
21%
510
78%
510
40%
859
July16th to endNight
80%
564
23%
1594
25%
531
83%
531
42%
864
August1st to 15thNight
86%
539
28%
1704
34%
536
86%
536
50%
818
August16th to endNight
76%
573
20%
1961
24%
573
76%
573
32%
1130
September1st to 15thNight
75%
540
20%
1980
24%
540
76%
540
31%
1096
September16th to endNight
66%
513
25%
1891
26%
513
69%
513
29%
1089
October1st to 15thNight
68%
495
34%
1815
33%
495
72%
495
38%
915
October16th to endNight
59%
695
36%
2103
23%
695
67%
695
46%
1073
November1st to 15thNight
50%
730
28%
2130
17%
730
56%
730
34%
1251
November16th to endNight
46%
900
30%
2340
14%
900
53%
900
38%
1397
December1st to 15thNight
40%
900
29%
2340
15%
900
47%
900
31%
1503
December16th to endNight
39%
960
24%
2496
12%
960
45%
960
29%
1639

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%24424447%45%
47858
Night
12%423323347%52%
47217
Cloud CoverDay
13%5%24424447%45%
47856
Night
12%413323347%52%
47217
TransparencyDay
39%49%19%17%9%
47556
Night
33%411%20%18%11%
47022
SeeingDay
14%5%18%31%23%5%
5373
Night
15%6%24%35%16%1
15424

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
16%424323226%49%
1611
16th to endDay
16%5%23222335%52%
1838
February1st to 15thDay
15%5%24323336%49%
1750
16th to endDay
17%6%23212435%50%
1580
March1st to 15thDay
20%5%23323235%46%
1947
16th to endDay
17%6%24323345%47%
2112
April1st to 15thDay
15%5%25%424346%46%
1971
16th to endDay
15%6%25%434335%43%
2193
May1st to 15thDay
17%7%36%5%25%45%6%36%
2331
16th to endDay
18%7%25%425%5%5%7%34%
2430
June1st to 15thDay
5%5%25%5%46%6%6%8%44%
2340
16th to endDay
11%6%36%6%36%5%6%8%34%
2340
July1st to 15thDay
10%5%26%5%35%5%6%9%39%
2340
16th to endDay
8%325%437%5%5%11%41%
2466
August1st to 15thDay
321332445%10%58%
2242
16th to endDay
8%5%35%6%45%5%7%8%39%
2241
September1st to 15thDay
10%6%35%7%35%45%6%40%
1980
16th to endDay
10%5%25%5%345%6%7%43%
1881
October1st to 15thDay
11%5%24424346%51%
1812
16th to endDay
8%313213346%61%
1760
November1st to 15thDay
13%6%36%5%2435%5%44%
1725
16th to endDay
14%5%2442223354%
1620
December1st to 15thDay
20%6%24312336%44%
1620
16th to endDay
15%8%2432343446%
1728
January1st to 15thNight
17%5%13323246%49%
2327
16th to endNight
16%5%23223335%51%
2397
February1st to 15thNight
15%6%1321323454%
2102
16th to endNight
15%413323335%51%
1894
March1st to 15thNight
16%6%24312236%50%
2010
16th to endNight
16%6%23222346%47%
2112
April1st to 15thNight
14%5%24323347%48%
1977
16th to endNight
18%5%24323335%46%
1764
May1st to 15thNight
14%5%243245%46%46%
1619
16th to endNight
11%5%2442345%10%45%
1683
June1st to 15thNight
4212323349%61%
1620
16th to endNight
7%32332446%8%53%
1620
July1st to 15thNight
6%2133245%6%11%51%
1620
16th to endNight
6%21232346%10%54%
1702
August1st to 15thNight
21231435%11%63%
1714
16th to endNight
7%4134345%6%10%47%
1961
September1st to 15thNight
8%5%2332445%8%50%
1980
16th to endNight
8%5%25%43345%8%48%
1891
October1st to 15thNight
10%313323336%59%
1815
16th to endNight
9%312213225%64%
2103
November1st to 15thNight
11%424423346%53%
2130
16th to endNight
15%5%13212225%57%
2340
December1st to 15thNight
17%5%24313236%49%
2340
16th to endNight
16%7%2432333447%
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
16%424323335%50%
1611
16th to endDay
15%5%13322325%52%
1838
February1st to 15thDay
15%6%23323236%50%
1750
16th to endDay
16%6%23312445%50%
1580
March1st to 15thDay
20%5%23323236%46%
1947
16th to endDay
17%6%24322345%47%
2110
April1st to 15thDay
15%5%24423346%45%
1971
16th to endDay
16%6%35%434335%43%
2193
May1st to 15thDay
17%6%36%43445%6%36%
2331
16th to endDay
18%7%35%425%45%7%35%
2430
June1st to 15thDay
5%5%35%5%46%5%6%8%44%
2340
16th to endDay
11%6%36%6%46%5%6%8%35%
2340
July1st to 15thDay
11%425%5%36%6%6%9%38%
2340
16th to endDay
8%3245%36%5%6%11%41%
2466
August1st to 15thDay
321333445%10%58%
2242
16th to endDay
9%5%35%6%45%6%6%8%38%
2241
September1st to 15thDay
11%6%35%6%35%5%5%6%40%
1980
16th to endDay
10%5%25%5%3446%7%43%
1881
October1st to 15thDay
12%424323346%51%
1812
16th to endDay
8%313312345%61%
1760
November1st to 15thDay
13%7%35%5%2435%5%43%
1725
16th to endDay
14%5%2431223453%
1620
December1st to 15thDay
20%6%24312336%45%
1620
16th to endDay
16%7%2441343447%
1728
January1st to 15thNight
17%5%13323336%49%
2327
16th to endNight
16%5%23223335%52%
2397
February1st to 15thNight
15%6%2231223455%
2102
16th to endNight
15%413323335%51%
1894
March1st to 15thNight
16%7%13313236%50%
2010
16th to endNight
17%5%23222345%48%
2112
April1st to 15thNight
15%5%24322346%49%
1977
16th to endNight
18%5%24323335%46%
1764
May1st to 15thNight
14%5%23333447%46%
1619
16th to endNight
12%6%1442345%9%46%
1683
June1st to 15thNight
5%21332235%8%62%
1620
16th to endNight
8%32332346%8%53%
1620
July1st to 15thNight
6%313325%5%7%11%50%
1620
16th to endNight
6%31232337%10%54%
1702
August1st to 15thNight
21232335%10%63%
1714
16th to endNight
7%4234245%6%10%47%
1961
September1st to 15thNight
9%4243245%5%9%49%
1980
16th to endNight
9%5%25%433448%48%
1891
October1st to 15thNight
10%33312336%59%
1815
16th to endNight
9%312212225%65%
2103
November1st to 15thNight
11%424422335%54%
2130
16th to endNight
14%5%13212125%58%
2340
December1st to 15thNight
17%5%23312236%49%
2340
16th to endNight
16%7%2432333447%
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
38%3318%20%14%
1612
16th to endDay
35%36%14%24%14%
1838
February1st to 15thDay
37%25%15%21%17%
1751
16th to endDay
37%35%18%21%14%
1580
March1st to 15thDay
42%37%13%19%13%
1947
16th to endDay
40%37%17%19%11%
2112
April1st to 15thDay
41%37%16%18%13%
1971
16th to endDay
44%35%18%15%11%
2193
May1st to 15thDay
47%5%8%14%17%6%
2331
16th to endDay
48%5%8%17%16%3
2434
June1st to 15thDay
35%6%9%21%21%5%
2340
16th to endDay
44%7%10%20%14%2
2340
July1st to 15thDay
38%7%14%25%12%1
2201
16th to endDay
34%7%19%28%10%
2311
August1st to 15thDay
21%5%17%38%16%1
2228
16th to endDay
41%7%15%23%9%2
2241
September1st to 15thDay
43%6%11%18%16%4
1980
16th to endDay
37%7%9%19%17%8%
1881
October1st to 15thDay
34%49%18%20%12%
1812
16th to endDay
24%45%18%26%20%
1760
November1st to 15thDay
41%36%20%16%10%
1725
16th to endDay
36%25%12%21%21%
1620
December1st to 15thDay
43%35%18%18%10%
1620
16th to endDay
41%47%15%21%10%
1728
January1st to 15thNight
37%25%16%18%18%
2327
16th to endNight
36%2416%22%17%
2397
February1st to 15thNight
34%2414%22%21%
2112
16th to endNight
35%26%16%22%16%
1894
March1st to 15thNight
38%27%15%19%15%
2010
16th to endNight
37%49%15%20%12%
2112
April1st to 15thNight
38%37%17%17%16%
1977
16th to endNight
42%48%17%15%12%
1764
May1st to 15thNight
37%412%18%16%9%
1620
16th to endNight
36%5%13%25%14%4
1685
June1st to 15thNight
21%413%30%25%4
1620
16th to endNight
29%6%17%28%15%2
1620
July1st to 15thNight
23%9%22%30%12%1
1530
16th to endNight
21%9%26%31%9%1
1594
August1st to 15thNight
16%6%20%39%14%
1704
16th to endNight
31%7%22%26%8%2
1961
September1st to 15thNight
31%5%17%23%16%5%
1980
16th to endNight
33%7%13%19%17%8%
1891
October1st to 15thNight
26%412%24%18%13%
1815
16th to endNight
24%25%17%28%21%
2103
November1st to 15thNight
33%48%21%19%13%
2130
16th to endNight
31%37%14%20%22%
2340
December1st to 15thNight
38%36%18%21%11%
2340
16th to endNight
41%25%14%22%13%
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
14%11%36%30%7%
90
16th to endDay
18%11%35%23%10%
96
February1st to 15thDay
12%25%30%22%8%1
90
16th to endDay
18%18%38%22%2
81
March1st to 15thDay
25%10%35%20%8%
90
16th to endDay
13%439%35%6%1
96
April1st to 15thDay
17%12%41%24%4
90
16th to endDay
16%12%39%25%5%
303
May1st to 15thDay
21%10%36%25%5%
468
16th to endDay
26%5%25%32%9%1
517
June1st to 15thDay
9%112%45%26%3
495
16th to endDay
11%310%36%29%7%
495
July1st to 15thDay
10%111%38%31%6%
475
16th to endDay
7%1428%48%9%
515
August1st to 15thDay
5%1431%43%13%
396
16th to endDay
14%17%37%26%12%
281
September1st to 15thDay
5%25%20%49%16%
135
16th to endDay
31220%54%16%
108
October1st to 15thDay
4441%40%10%
90
16th to endDay
18%214%32%29%3
96
November1st to 15thDay
28%6%26%23%10%4
90
16th to endDay
26%12%28%17%11%3
90
December1st to 15thDay
25%5%22%23%15%7%
90
16th to endDay
26%10%38%20%31
96
January1st to 15thNight
20%10%27%32%8%
900
16th to endNight
20%10%29%31%8%
861
February1st to 15thNight
20%13%28%30%6%
704
16th to endNight
21%12%40%23%2
632
March1st to 15thNight
19%9%35%29%5%
570
16th to endNight
19%10%36%28%4
576
April1st to 15thNight
16%10%42%26%3
539
16th to endNight
21%6%41%24%5%
540
May1st to 15thNight
15%8%41%29%4
540
16th to endNight
15%433%34%12%
563
June1st to 15thNight
5%26%46%19%1
540
16th to endNight
7%119%47%21%2
540
July1st to 15thNight
6%10%49%29%2
510
16th to endNight
7%450%32%3
564
August1st to 15thNight
25%48%39%4
539
16th to endNight
10%1444%35%4
573
September1st to 15thNight
11%5%39%36%6%
540
16th to endNight
11%19%32%38%5%
513
October1st to 15thNight
11%213%42%25%4
495
16th to endNight
10%5%21%34%24%3
695
November1st to 15thNight
13%6%24%35%18%2
730
16th to endNight
18%9%22%33%14%1
900
December1st to 15thNight
21%10%24%31%11%1
900
16th to endNight
21%9%25%33%9%
960
Page generated at 2017-09-23 05:43:41. Version ac04

Copyright 2017 A. Danko


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