Fiddletown
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fiddletown clear sky chart from 2005-11-05 to 2018-02-22.

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
70%
15893
28%
48905
27%
15858
72%
15858
41%
26120

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%
777
20%
2691
21%
776
64%
776
29%
1552
January16th to endNight
57%
832
24%
2704
23%
832
61%
832
28%
1652
February1st to 15thNight
58%
758
26%
2432
26%
757
62%
757
29%
1472
February16th to endNight
55%
660
26%
1979
24%
660
60%
660
29%
1242
March1st to 15thNight
54%
720
17%
2082
17%
720
56%
720
26%
1381
March16th to endNight
55%
768
20%
2042
16%
768
58%
768
29%
1353
April1st to 15thNight
57%
719
19%
1799
12%
719
59%
719
30%
1218
April16th to endNight
64%
720
24%
1800
13%
720
67%
720
43%
1085
May1st to 15thNight
72%
587
28%
1667
21%
587
74%
587
55%
817
May16th to endNight
78%
374
26%
1496
31%
374
80%
374
42%
666
June1st to 15thNight
80%
360
28%
1440
35%
360
84%
360
49%
586
June16th to endNight
89%
360
37%
1440
50%
360
91%
360
69%
465
July1st to 15thNight
96%
340
34%
1360
47%
340
96%
340
75%
420
July16th to endNight
91%
480
39%
1512
40%
450
92%
450
69%
574
August1st to 15thNight
90%
598
37%
1671
29%
595
90%
595
74%
711
August16th to endNight
93%
764
44%
1910
29%
764
93%
764
82%
860
September1st to 15thNight
92%
720
43%
1800
31%
720
92%
720
81%
811
September16th to endNight
85%
716
45%
1929
40%
716
88%
716
71%
880
October1st to 15thNight
75%
720
30%
2160
33%
720
78%
720
51%
1055
October16th to endNight
77%
768
38%
2304
40%
768
81%
768
53%
1129
November1st to 15thNight
71%
760
27%
2458
30%
760
74%
760
40%
1292
November16th to endNight
61%
780
26%
2587
27%
780
65%
780
33%
1459
December1st to 15thNight
60%
780
22%
2730
22%
780
64%
780
28%
1594
December16th to endNight
48%
832
22%
2912
21%
832
54%
832
22%
1846

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
10%312212335%62%
49347
Night
11%312212335%60%
49096
TransparencyDay
25%37%18%24%20%
49028
Night
27%38%18%23%18%
48915
SeeingDay
12%8%27%32%14%5%
6332
Night
13%29%32%33%9%
15904

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
18%5%12224346%47%
1575
16th to endDay
20%7%13323336%43%
1872
February1st to 15thDay
18%5%23323245%48%
1752
16th to endDay
22%8%34322435%39%
1641
March1st to 15thDay
20%7%25%323447%38%
1878
16th to endDay
18%7%15%324436%41%
2181
April1st to 15thDay
17%7%2432335%6%43%
2149
16th to endDay
14%312212346%57%
2160
May1st to 15thDay
6%312213336%65%
2281
16th to endDay
8%314323336%58%
2615
June1st to 15thDay
5%313212235%66%
2520
16th to endDay
11111113283%
2520
July1st to 15thDay
11112285%
2520
16th to endDay
1112112284%
2550
August1st to 15thDay
1111112285%
2280
16th to endDay
1111122384%
2292
September1st to 15thDay
1111122383%
2160
16th to endDay
3211222377%
2027
October1st to 15thDay
6%21221235%5%66%
1800
16th to endDay
7%212323335%61%
1920
November1st to 15thDay
11%413324346%53%
1730
16th to endDay
14%5%13333345%50%
1700
December1st to 15thDay
18%6%24322325%47%
1560
16th to endDay
22%6%24323447%39%
1664
January1st to 15thNight
18%42331335%7%46%
2691
16th to endNight
18%5%13423336%46%
2704
February1st to 15thNight
16%5%14423346%46%
2430
16th to endNight
20%6%2332334447%
1979
March1st to 15thNight
20%7%24323345%42%
2082
16th to endNight
20%5%23213336%46%
2042
April1st to 15thNight
15%5%24424445%44%
1799
16th to endNight
11%412212346%57%
1800
May1st to 15thNight
7%11121225%6%66%
1667
16th to endNight
7%313213337%63%
1496
June1st to 15thNight
422213335%70%
1440
16th to endNight
1121112284%
1440
July1st to 15thNight
11123284%
1440
16th to endNight
111111121283%
1616
August1st to 15thNight
1111123480%
1680
16th to endNight
1112484%
1910
September1st to 15thNight
111112385%
1800
16th to endNight
21111232379%
1929
October1st to 15thNight
6%212212335%68%
2160
16th to endNight
7%21212336%66%
2304
November1st to 15thNight
12%312213336%58%
2458
16th to endNight
14%323423346%52%
2587
December1st to 15thNight
18%5%13322346%48%
2730
16th to endNight
24%6%13313335%41%
2912

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
37%5%10%20%17%8%
1575
16th to endDay
42%49%15%16%11%
1872
February1st to 15thDay
38%39%20%20%6%
1752
16th to endDay
47%38%24%13%2
1641
March1st to 15thDay
44%5%11%16%16%5%
1878
16th to endDay
43%5%13%18%15%3
2181
April1st to 15thDay
41%411%22%14%4
2149
16th to endDay
28%413%25%23%5%
2160
May1st to 15thDay
19%39%29%30%7%
2281
16th to endDay
26%5%10%28%21%7%
2619
June1st to 15thDay
20%39%22%23%20%
2520
16th to endDay
8%1313%34%37%
2520
July1st to 15thDay
7%127%25%55%
2371
16th to endDay
8%1310%23%52%
2392
August1st to 15thDay
7%1210%30%48%
2264
16th to endDay
6%1210%37%40%
2292
September1st to 15thDay
7%2312%33%39%
2160
16th to endDay
12%25%22%34%22%
2027
October1st to 15thDay
17%46%22%26%22%
1800
16th to endDay
23%37%22%24%17%
1920
November1st to 15thDay
30%412%23%20%9%
1730
16th to endDay
35%48%20%25%5%
1700
December1st to 15thDay
40%28%18%20%9%
1560
16th to endDay
43%410%15%17%7%
1664
January1st to 15thNight
36%411%21%17%9%
2691
16th to endNight
40%39%14%18%14%
2704
February1st to 15thNight
37%47%19%20%10%
2441
16th to endNight
39%49%25%16%4
1979
March1st to 15thNight
43%410%16%17%6%
2082
16th to endNight
40%5%9%20%17%6%
2042
April1st to 15thNight
40%5%13%20%14%5%
1799
16th to endNight
27%6%11%26%21%7%
1800
May1st to 15thNight
18%312%24%28%12%
1668
16th to endNight
21%413%29%21%9%
1496
June1st to 15thNight
16%411%24%22%20%
1440
16th to endNight
9%315%33%37%
1440
July1st to 15thNight
6%136%24%57%
1360
16th to endNight
9%237%22%54%
1512
August1st to 15thNight
8%2214%25%46%
1671
16th to endNight
6%1211%33%44%
1910
September1st to 15thNight
6%1411%37%38%
1800
16th to endNight
10%2420%37%23%
1929
October1st to 15thNight
19%36%20%25%24%
2160
16th to endNight
19%36%22%27%21%
2304
November1st to 15thNight
27%312%22%21%12%
2458
16th to endNight
33%37%22%24%8%
2587
December1st to 15thNight
36%49%17%18%12%
2730
16th to endNight
45%38%14%18%8%
2912

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
36%221%20%15%4
113
16th to endDay
26%6%22%24%17%4
304
February1st to 15thDay
20%7%21%32%13%4
292
16th to endDay
26%14%21%25%12%
264
March1st to 15thDay
24%18%21%21%11%2
270
16th to endDay
25%13%30%19%11%
288
April1st to 15thDay
23%17%31%18%5%2
269
16th to endDay
16%19%28%23%10%1
270
May1st to 15thDay
9%12%38%26%8%4
288
16th to endDay
10%14%21%32%14%6%
330
June1st to 15thDay
9%13%31%33%8%5%
315
16th to endDay
2333%42%11%7%
315
July1st to 15thDay
23%53%11%10%
305
16th to endDay
129%47%13%7%
327
August1st to 15thDay
2134%43%11%6%
315
16th to endDay
226%46%15%9%
332
September1st to 15thDay
2230%41%18%4
315
16th to endDay
38%28%40%17%2
315
October1st to 15thDay
5%11%32%31%15%3
315
16th to endDay
10%8%24%26%25%5%
336
November1st to 15thDay
17%315%26%28%8%
146
16th to endDay
18%9%15%31%22%4
122
December1st to 15thDay
18%5%26%20%14%14%
90
16th to endDay
18%419%22%22%11%
96
January1st to 15thNight
18%310%32%25%9%
780
16th to endNight
21%210%30%24%9%
832
February1st to 15thNight
18%312%32%26%7%
764
16th to endNight
22%413%31%21%6%
660
March1st to 15thNight
21%5%10%30%25%6%
720
16th to endNight
21%414%29%26%5%
768
April1st to 15thNight
19%411%37%23%3
719
16th to endNight
12%313%35%26%8%
720
May1st to 15thNight
9%113%37%32%5%
588
16th to endNight
8%27%31%45%5%
375
June1st to 15thNight
5%9%33%44%6%
360
16th to endNight
1435%51%6%
360
July1st to 15thNight
29%63%5%
340
16th to endNight
21225%56%13%
480
August1st to 15thNight
2332%52%8%
598
16th to endNight
333%52%9%
764
September1st to 15thNight
1329%53%11%
720
16th to endNight
27%34%39%15%
716
October1st to 15thNight
7%29%36%31%11%
720
16th to endNight
8%19%27%34%17%
768
November1st to 15thNight
14%17%34%29%11%
760
16th to endNight
16%213%31%25%10%
780
December1st to 15thNight
21%39%33%23%8%
780
16th to endNight
28%213%27%21%6%
832
Page generated at 2018-02-23 08:21:33. Version ac04

Copyright 2018 A. Danko


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