F.D.A.T. Veteran's Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the F.D.A.T. Veteran's Point clear sky chart from 2005-11-05 to 2017-09-20.

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
61%
16005
21%
46957
17%
15964
66%
15964
31%
29071

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
46%
718
21%
2327
15%
716
54%
716
26%
1424
January16th to endNight
45%
768
24%
2487
18%
768
55%
768
29%
1496
February1st to 15thNight
45%
701
25%
2103
17%
698
55%
698
34%
1227
February16th to endNight
48%
631
26%
1810
16%
631
58%
631
34%
1076
March1st to 15thNight
56%
720
30%
1980
20%
720
64%
720
46%
1084
March16th to endNight
57%
768
26%
2112
19%
768
62%
768
42%
1203
April1st to 15thNight
59%
718
24%
1976
18%
718
63%
718
43%
1107
April16th to endNight
64%
720
28%
1815
19%
720
66%
720
43%
1076
May1st to 15thNight
70%
599
26%
1679
19%
599
73%
599
44%
926
May16th to endNight
74%
561
22%
1682
18%
561
75%
561
33%
1019
June1st to 15thNight
69%
540
14%
1620
12%
540
69%
540
25%
1092
June16th to endNight
69%
540
9%
1620
8%
540
69%
540
24%
1125
July1st to 15thNight
72%
510
8%
1530
6%
510
72%
510
22%
1071
July16th to endNight
75%
564
9%
1595
9%
531
76%
531
23%
1092
August1st to 15thNight
82%
539
9%
1609
8%
536
82%
536
28%
1058
August16th to endNight
66%
739
10%
2006
9%
739
66%
739
24%
1405
September1st to 15thNight
68%
720
10%
1980
9%
720
68%
720
21%
1424
September16th to endNight
61%
677
13%
1870
13%
677
62%
677
20%
1375
October1st to 15thNight
69%
660
27%
1899
28%
660
71%
660
33%
1177
October16th to endNight
64%
704
27%
2112
28%
704
69%
704
35%
1248
November1st to 15thNight
63%
700
29%
2101
25%
700
69%
700
36%
1218
November16th to endNight
56%
720
29%
2208
24%
720
65%
720
34%
1282
December1st to 15thNight
55%
720
27%
2340
24%
720
62%
720
29%
1385
December16th to endNight
55%
768
23%
2496
21%
768
62%
768
29%
1481

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
8%5%36%7%46%6%6%8%35%
47861
Night
8%5%25%5%35%5%6%9%43%
47166
TransparencyDay
43%6%13%17%13%5%
47562
Night
35%6%16%21%14%6%
46969
SeeingDay
9%211%20%26%29%
5843
Night
9%314%31%32%9%
16013

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
10%6%35%6%45%45%8%39%
1611
16th to endDay
10%5%25%43445%7%45%
1735
February1st to 15thDay
10%6%25%6%35%446%44%
1750
16th to endDay
9%435%6%35%447%44%
1661
March1st to 15thDay
6%3245%36%45%9%48%
1980
16th to endDay
8%4246%35%5%47%47%
2111
April1st to 15thDay
7%315%5%45%5%6%9%45%
1972
16th to endDay
6%325%6%35%6%6%8%44%
2145
May1st to 15thDay
6%3245%26%6%6%7%47%
2280
16th to endDay
8%426%6%47%6%7%9%34%
2431
June1st to 15thDay
10%5%37%9%47%7%7%9%25%
2340
16th to endDay
9%6%37%7%6%8%7%8%9%24%
2340
July1st to 15thDay
9%6%47%8%5%9%7%7%9%21%
2340
16th to endDay
8%7%48%9%5%8%7%7%8%23%
2465
August1st to 15thDay
6%6%39%10%6%8%7%8%11%22%
2340
16th to endDay
10%7%39%9%48%6%7%8%22%
2177
September1st to 15thDay
9%6%37%10%6%7%8%7%8%23%
1980
16th to endDay
13%8%48%9%5%7%6%7%9%20%
1859
October1st to 15thDay
9%6%27%6%36%6%6%7%35%
1730
16th to endDay
10%425%5%36%45%7%43%
1760
November1st to 15thDay
6%425%5%36%5%7%9%44%
1757
16th to endDay
9%7%35%6%35%5%47%42%
1749
December1st to 15thDay
10%5%36%5%3446%8%39%
1620
16th to endDay
7%6%25%6%35%5%6%8%42%
1728
January1st to 15thNight
10%6%36%43446%8%41%
2327
16th to endNight
13%5%25%4245%5%6%44%
2487
February1st to 15thNight
11%5%24324445%51%
2103
16th to endNight
8%4245%35%35%7%50%
1810
March1st to 15thNight
6%31342345%8%55%
1980
16th to endNight
5%324423446%57%
2112
April1st to 15thNight
5%42342347%8%54%
1976
16th to endNight
6%32442446%8%53%
1815
May1st to 15thNight
5%21342445%8%56%
1679
16th to endNight
6%3245%25%6%7%9%44%
1682
June1st to 15thNight
7%5%26%6%36%6%8%10%33%
1620
16th to endNight
7%446%7%46%6%8%10%32%
1620
July1st to 15thNight
7%5%17%6%36%8%8%10%32%
1620
16th to endNight
5%5%35%8%47%6%8%10%33%
1703
August1st to 15thNight
3325%6%47%7%9%13%35%
1620
16th to endNight
9%7%27%6%35%6%7%11%31%
2006
September1st to 15thNight
7%5%25%6%5%8%7%7%10%31%
1980
16th to endNight
9%7%28%7%47%8%6%10%26%
1870
October1st to 15thNight
6%6%25%5%35%46%8%45%
1899
16th to endNight
9%5%245%24448%48%
2112
November1st to 15thNight
5%425%5%345%7%7%47%
2101
16th to endNight
8%42443446%8%47%
2208
December1st to 15thNight
10%4245%35%5%5%8%44%
2340
16th to endNight
8%434436%5%6%9%43%
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%28%20%16%7%
1612
16th to endDay
37%38%18%20%11%
1735
February1st to 15thDay
40%37%14%20%13%
1752
16th to endDay
38%310%16%20%10%
1661
March1st to 15thDay
33%310%27%17%8%
1980
16th to endDay
36%311%20%20%7%
2112
April1st to 15thDay
34%5%9%21%22%7%
1972
16th to endDay
35%49%21%19%8%
2145
May1st to 15thDay
33%411%23%19%7%
2280
16th to endDay
42%416%19%13%2
2435
June1st to 15thDay
50%6%17%20%4
2340
16th to endDay
51%8%22%14%3
2340
July1st to 15thDay
51%11%21%13%1
2201
16th to endDay
53%10%20%14%1
2310
August1st to 15thDay
50%10%26%11%1
2327
16th to endDay
54%10%20%12%1
2177
September1st to 15thDay
54%9%19%12%4
1980
16th to endDay
56%7%15%12%6%1
1859
October1st to 15thDay
45%5%9%16%16%7%
1730
16th to endDay
39%46%16%22%10%
1760
November1st to 15thDay
34%47%22%23%7%
1757
16th to endDay
42%37%18%18%10%
1749
December1st to 15thDay
41%411%21%15%5%
1620
16th to endDay
38%413%20%14%7%
1728
January1st to 15thNight
40%39%22%15%7%
2327
16th to endNight
38%38%19%20%9%
2487
February1st to 15thNight
34%29%18%18%15%
2112
16th to endNight
32%5%12%19%21%8%
1810
March1st to 15thNight
25%313%29%20%6%
1980
16th to endNight
27%413%24%20%9%
2112
April1st to 15thNight
26%414%25%19%8%
1976
16th to endNight
28%411%27%20%7%
1815
May1st to 15thNight
26%416%27%17%8%
1680
16th to endNight
32%7%16%25%16%1
1684
June1st to 15thNight
41%8%21%24%3
1620
16th to endNight
42%9%24%18%4
1620
July1st to 15thNight
41%12%28%14%2
1530
16th to endNight
38%13%28%16%2
1595
August1st to 15thNight
33%12%38%13%1
1609
16th to endNight
42%10%28%16%1
2006
September1st to 15thNight
42%14%22%16%5%
1980
16th to endNight
49%9%17%17%41
1870
October1st to 15thNight
35%5%10%21%19%6%
1899
16th to endNight
34%39%18%23%9%
2112
November1st to 15thNight
33%311%22%22%7%
2101
16th to endNight
33%49%22%18%11%
2208
December1st to 15thNight
37%311%27%13%6%
2340
16th to endNight
36%413%24%13%7%
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
16%6%30%28%8%8%
90
16th to endDay
13%13%33%21%13%4
96
February1st to 15thDay
6%13%26%27%18%6%
90
16th to endDay
11%8%30%29%18%1
162
March1st to 15thDay
5%7%28%32%22%3
270
16th to endDay
9%321%29%28%7%
288
April1st to 15thDay
5%422%29%26%11%
270
16th to endDay
7%214%25%28%21%
270
May1st to 15thDay
5%313%21%31%24%
288
16th to endDay
7%15%18%30%37%
331
June1st to 15thDay
13%15%17%25%36%
315
16th to endDay
7%213%23%52%
315
July1st to 15thDay
5%5%23%63%
305
16th to endDay
10%10%25%52%
326
August1st to 15thDay
6%311%22%56%
313
16th to endDay
14%16%22%53%
332
September1st to 15thDay
13%339%25%44%
315
16th to endDay
12%1112%30%41%
270
October1st to 15thDay
14%8%22%39%15%
255
16th to endDay
10%116%29%30%11%
272
November1st to 15thDay
7%211%31%36%10%
265
16th to endDay
10%122%36%22%5%
219
December1st to 15thDay
7%437%34%15%
90
16th to endDay
4318%41%26%6%
96
January1st to 15thNight
13%426%34%19%1
720
16th to endNight
15%5%26%37%14%
768
February1st to 15thNight
12%430%35%14%1
704
16th to endNight
9%431%44%10%
631
March1st to 15thNight
6%427%44%16%1
720
16th to endNight
6%423%41%22%1
768
April1st to 15thNight
6%223%41%24%1
718
16th to endNight
7%316%45%25%1
720
May1st to 15thNight
7%211%44%31%3
600
16th to endNight
9%429%44%11%
563
June1st to 15thNight
10%1323%47%14%
540
16th to endNight
8%213%48%25%
540
July1st to 15thNight
10%110%48%28%
510
16th to endNight
5%110%53%28%
564
August1st to 15thNight
411%52%30%
539
16th to endNight
11%3114%43%25%
739
September1st to 15thNight
10%1116%47%21%
720
16th to endNight
12%2119%47%16%
677
October1st to 15thNight
10%25%30%41%9%
660
16th to endNight
11%211%34%34%5%
704
November1st to 15thNight
6%215%39%32%3
700
16th to endNight
10%321%38%23%2
720
December1st to 15thNight
10%420%36%25%2
720
16th to endNight
10%421%35%26%1
768
Page generated at 2017-09-21 07:18:12. Version ac04

Copyright 2017 A. Danko


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