Franklin Mountains State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Franklin Mountains 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
65%
15336
34%
47127
26%
15297
74%
15297
47%
23232

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
62%
716
33%
2327
28%
716
71%
716
45%
1134
January16th to endNight
60%
768
35%
2496
29%
768
71%
768
41%
1246
February1st to 15thNight
63%
702
37%
2153
27%
699
74%
699
53%
982
February16th to endNight
50%
632
39%
1894
25%
632
66%
632
51%
906
March1st to 15thNight
56%
720
38%
1980
22%
720
67%
720
50%
1014
March16th to endNight
57%
744
39%
2088
21%
744
71%
744
54%
1010
April1st to 15thNight
45%
539
37%
1798
21%
539
67%
539
47%
801
April16th to endNight
49%
540
42%
1800
27%
540
74%
540
57%
714
May1st to 15thNight
49%
539
32%
1799
23%
539
66%
539
50%
777
May16th to endNight
56%
561
32%
1806
24%
561
69%
561
51%
823
June1st to 15thNight
70%
540
29%
1620
24%
540
77%
540
54%
757
June16th to endNight
72%
540
23%
1620
20%
540
75%
540
44%
852
July1st to 15thNight
77%
510
22%
1530
19%
510
78%
510
38%
872
July16th to endNight
74%
564
23%
1593
20%
531
75%
531
34%
946
August1st to 15thNight
77%
539
20%
1778
23%
536
77%
536
30%
1070
August16th to endNight
80%
573
23%
1910
27%
573
80%
573
34%
1093
September1st to 15thNight
76%
540
26%
1800
29%
540
77%
540
32%
1037
September16th to endNight
75%
551
37%
1842
32%
551
81%
551
47%
879
October1st to 15thNight
74%
660
35%
1980
28%
660
78%
660
53%
954
October16th to endNight
77%
704
41%
2112
30%
704
83%
704
64%
922
November1st to 15thNight
71%
700
43%
2100
29%
700
80%
700
62%
920
November16th to endNight
66%
798
41%
2238
27%
798
73%
798
53%
1108
December1st to 15thNight
65%
888
38%
2367
26%
888
72%
888
54%
1224
December16th to endNight
61%
768
38%
2496
31%
768
71%
768
46%
1191

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
3212323347%64%
47731
Night
421332335%7%62%
47329
TransparencyDay
19%36%16%27%26%
47428
Night
20%36%16%26%26%
47134
SeeingDay
5%9%20%29%26%9%
5040
Night
4419%41%26%2
15345

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
3313324346%63%
1611
16th to endDay
7%313323445%61%
1728
February1st to 15thDay
312213345%69%
1704
16th to endDay
221131323472%
1580
March1st to 15thDay
2312312347%66%
1977
16th to endDay
2113212235%73%
2134
April1st to 15thDay
1212212236%72%
2150
16th to endDay
11111212381%
2160
May1st to 15thDay
111213346%73%
2151
16th to endDay
112235%78%
2303
June1st to 15thDay
11212235%77%
2340
16th to endDay
111132446%8%63%
2340
July1st to 15thDay
32245%36%6%7%10%46%
2340
16th to endDay
6%3245%45%6%8%10%41%
2467
August1st to 15thDay
5%213436%6%7%11%48%
2170
16th to endDay
4315%5%36%6%8%9%45%
2292
September1st to 15thDay
8%42443446%8%48%
2160
16th to endDay
423212346%67%
1927
October1st to 15thDay
5%212322235%68%
1650
16th to endDay
21211222478%
1760
November1st to 15thDay
212312236%71%
1759
16th to endDay
422212235%70%
1704
December1st to 15thDay
4312213348%64%
1596
16th to endDay
5%313422345%62%
1728
January1st to 15thNight
4414323235%63%
2327
16th to endNight
7%213323345%61%
2496
February1st to 15thNight
221231335%6%67%
2147
16th to endNight
421231223470%
1894
March1st to 15thNight
332321335%6%64%
1980
16th to endNight
221322323470%
2088
April1st to 15thNight
321222345%6%66%
1798
16th to endNight
11121123478%
1800
May1st to 15thNight
3112122345%71%
1799
16th to endNight
3112213346%68%
1806
June1st to 15thNight
21222446%9%63%
1620
16th to endNight
21135%35%5%8%11%52%
1620
July1st to 15thNight
3325%437%5%8%12%43%
1620
16th to endNight
4415%6%35%6%9%14%37%
1701
August1st to 15thNight
5%3147%47%8%10%13%34%
1788
16th to endNight
42145%36%7%8%12%43%
1910
September1st to 15thNight
6%315%435%5%7%9%46%
1800
16th to endNight
421332335%7%61%
1842
October1st to 15thNight
321232235%7%64%
1980
16th to endNight
211112235%76%
2112
November1st to 15thNight
221212335%75%
2100
16th to endNight
4313312235%68%
2238
December1st to 15thNight
5%21221335%6%64%
2367
16th to endNight
5%21422334465%
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
23%2320%31%17%
1612
16th to endDay
24%2317%34%17%
1728
February1st to 15thDay
16%25%16%30%29%
1705
16th to endDay
15%2215%35%28%
1580
March1st to 15thDay
17%2213%33%29%
1977
16th to endDay
15%1211%32%36%
2134
April1st to 15thDay
14%2210%33%36%
2150
16th to endDay
10%116%25%53%
2160
May1st to 15thDay
13%1310%25%45%
2151
16th to endDay
9%2410%25%46%
2306
June1st to 15thDay
10%2310%24%48%
2340
16th to endDay
16%47%13%23%35%
2340
July1st to 15thDay
27%7%12%21%18%13%
2201
16th to endDay
31%8%17%24%14%3
2312
August1st to 15thDay
25%8%14%25%20%4
2156
16th to endDay
29%7%14%20%19%8%
2292
September1st to 15thDay
31%410%21%19%12%
2160
16th to endDay
19%3419%33%20%
1927
October1st to 15thDay
19%25%14%28%29%
1650
16th to endDay
12%1218%32%32%
1760
November1st to 15thDay
15%2320%32%26%
1759
16th to endDay
17%1217%35%25%
1704
December1st to 15thDay
18%35%25%35%11%
1596
16th to endDay
22%36%25%32%8%
1728
January1st to 15thNight
23%25%17%31%19%
2327
16th to endNight
24%3216%33%19%
2496
February1st to 15thNight
17%2415%26%34%
2157
16th to endNight
19%1211%33%31%
1894
March1st to 15thNight
20%3214%28%30%
1980
16th to endNight
17%1210%29%37%
2088
April1st to 15thNight
17%338%31%34%
1798
16th to endNight
11%219%23%51%
1800
May1st to 15thNight
15%339%25%43%
1800
16th to endNight
17%35%11%21%39%
1808
June1st to 15thNight
16%45%12%15%45%
1620
16th to endNight
24%410%13%18%29%
1620
July1st to 15thNight
27%8%11%23%17%11%
1530
16th to endNight
32%6%21%22%13%4
1593
August1st to 15thNight
33%8%16%21%13%5%
1778
16th to endNight
29%8%15%21%15%8%
1910
September1st to 15thNight
30%8%12%19%17%12%
1800
16th to endNight
21%46%19%28%20%
1842
October1st to 15thNight
19%26%15%22%32%
1980
16th to endNight
13%2215%24%41%
2112
November1st to 15thNight
13%2216%34%30%
2100
16th to endNight
20%1311%32%30%
2238
December1st to 15thNight
19%25%22%31%19%
2367
16th to endNight
21%2423%36%11%
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%430%35%14%3
90
16th to endDay
6%12%25%38%8%9%
96
February1st to 15thDay
7%11%10%32%30%8%
90
16th to endDay
212%27%37%16%4
81
March1st to 15thDay
6%15%34%26%13%3
267
16th to endDay
421%30%27%11%5%
288
April1st to 15thDay
7%21%31%25%12%1
269
16th to endDay
323%38%23%9%1
270
May1st to 15thDay
223%36%26%12%
288
16th to endDay
13%33%37%13%
330
June1st to 15thDay
3419%37%26%7%
315
16th to endDay
216%32%38%9%
315
July1st to 15thDay
47%35%39%12%
305
16th to endDay
5%1424%39%25%
327
August1st to 15thDay
4420%43%26%
315
16th to endDay
5%5%28%38%21%
332
September1st to 15thDay
7%18%35%34%11%
315
16th to endDay
8%114%25%40%9%
195
October1st to 15thDay
12%213%18%37%15%
90
16th to endDay
4217%29%25%21%
96
November1st to 15thDay
6%7%22%26%24%12%
90
16th to endDay
11%16%28%22%18%2
90
December1st to 15thDay
8%6%21%31%26%5%
90
16th to endDay
8%16%20%39%14%
96
January1st to 15thNight
6%321%45%20%2
720
16th to endNight
7%5%19%45%18%2
768
February1st to 15thNight
46%23%41%22%1
704
16th to endNight
5%8%32%41%11%
632
March1st to 15thNight
6%8%24%42%16%1
720
16th to endNight
29%26%44%15%1
744
April1st to 15thNight
311%36%36%10%
539
16th to endNight
212%34%38%11%
540
May1st to 15thNight
310%35%42%8%
540
16th to endNight
36%30%43%15%
563
June1st to 15thNight
1220%49%24%1
540
16th to endNight
216%50%27%2
540
July1st to 15thNight
36%44%40%3
510
16th to endNight
416%28%54%5%
564
August1st to 15thNight
5%226%55%9%
539
16th to endNight
5%5%25%55%8%
573
September1st to 15thNight
6%6%38%43%3
540
16th to endNight
6%10%44%33%3
551
October1st to 15thNight
4213%48%28%2
660
16th to endNight
3214%41%32%5%
704
November1st to 15thNight
3220%39%32%3
700
16th to endNight
6%417%39%27%3
798
December1st to 15thNight
7%5%17%45%23%1
888
16th to endNight
5%5%21%47%17%2
768
Page generated at 2017-09-23 05:43:39. Version ac04

Copyright 2017 A. Danko


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