Stone Tavern Farm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stone Tavern Farm clear sky chart from 2005-11-05 to 2017-09-19.

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
26%
14903
13%
46873
7%
14872
33%
14872
14%
34138

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
12%
720
10%
2506
5%
716
19%
716
7%
1965
January16th to endNight
12%
768
10%
2610
3%
768
21%
768
7%
2030
February1st to 15thNight
5%
704
8%
2269
0%
701
13%
701
5%
1872
February16th to endNight
12%
631
13%
1893
5%
631
23%
631
8%
1476
March1st to 15thNight
13%
720
11%
2133
4%
720
21%
720
10%
1648
March16th to endNight
21%
768
17%
2007
7%
768
29%
768
14%
1492
April1st to 15thNight
17%
718
12%
1796
2%
718
23%
718
13%
1391
April16th to endNight
25%
701
15%
1781
4%
701
32%
701
20%
1288
May1st to 15thNight
30%
436
16%
1516
11%
436
38%
436
16%
1051
May16th to endNight
36%
374
13%
1497
11%
374
44%
374
15%
985
June1st to 15thNight
35%
360
11%
1440
11%
360
43%
360
12%
977
June16th to endNight
50%
360
10%
1440
11%
360
56%
360
23%
851
July1st to 15thNight
49%
340
11%
1360
14%
340
54%
340
20%
834
July16th to endNight
56%
376
14%
1418
16%
354
60%
354
23%
843
August1st to 15thNight
48%
498
14%
1569
9%
496
52%
496
24%
1010
August16th to endNight
54%
764
18%
1910
10%
764
56%
764
31%
1276
September1st to 15thNight
42%
720
17%
1800
8%
720
46%
720
28%
1233
September16th to endNight
46%
673
23%
1831
16%
673
50%
673
29%
1179
October1st to 15thNight
33%
660
18%
1961
11%
660
41%
660
18%
1381
October16th to endNight
21%
704
10%
2197
4%
704
29%
704
11%
1651
November1st to 15thNight
23%
700
15%
2277
8%
700
33%
700
13%
1627
November16th to endNight
21%
720
13%
2454
9%
720
28%
720
11%
1803
December1st to 15thNight
14%
720
7%
2520
3%
720
19%
720
6%
2045
December16th to endNight
11%
768
7%
2688
2%
768
16%
768
4%
2230

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
16%10%47%6%35%45%6%28%
47950
Night
14%10%5%8%6%34446%31%
47043
Cloud CoverDay
15%10%48%6%35%45%6%28%
47959
Night
13%10%5%8%6%34446%31%
47049
TransparencyDay
54%6%10%16%9%1
47638
Night
53%6%11%17%9%1
46873
SeeingDay
23%17%25%18%9%4
5685
Night
24%19%24%21%8%1
14904

By Month

Percentage Cloud Cover NE (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%11%8%12%10%36%5%45%21%
1432
16th to endDay
9%12%7%13%10%5%5%45%321%
1614
February1st to 15thDay
12%14%8%10%11%45%44418%
1592
16th to endDay
13%13%5%11%9%3445%423%
1580
March1st to 15thDay
14%14%6%9%6%34446%25%
1814
16th to endDay
15%11%7%8%5%2335%6%31%
2217
April1st to 15thDay
16%14%5%7%5%24335%31%
2152
16th to endDay
16%11%26%5%34346%35%
2178
May1st to 15thDay
21%11%37%434445%29%
2445
16th to endDay
15%8%35%7%35%5%5%7%31%
2618
June1st to 15thDay
23%6%36%5%35%45%9%27%
2520
16th to endDay
18%7%36%6%45%5%7%7%26%
2520
July1st to 15thDay
15%5%36%6%5%6%5%6%8%28%
2520
16th to endDay
14%6%35%6%46%5%7%8%31%
2654
August1st to 15thDay
17%7%36%7%45%6%6%7%27%
2364
16th to endDay
15%436%6%35%5%6%9%32%
2292
September1st to 15thDay
17%6%37%5%3435%7%35%
2160
16th to endDay
15%5%25%424446%43%
1875
October1st to 15thDay
20%10%25%5%34445%33%
1667
16th to endDay
21%16%46%433445%24%
1673
November1st to 15thDay
15%14%47%5%34345%31%
1581
16th to endDay
15%14%47%6%45%446%27%
1506
December1st to 15thDay
14%17%8%12%6%34335%19%
1440
16th to endDay
14%16%12%13%7%35%44415%
1536
January1st to 15thNight
12%12%6%13%8%45%5%46%21%
2506
16th to endNight
10%12%8%11%8%46%446%22%
2610
February1st to 15thNight
11%13%8%12%9%5%6%5%4418%
2268
16th to endNight
12%10%6%10%8%46%445%24%
1893
March1st to 15thNight
14%11%6%10%9%4434426%
2120
16th to endNight
15%10%6%8%6%23336%32%
2007
April1st to 15thNight
15%14%5%7%5%34446%29%
1796
16th to endNight
17%12%34433335%39%
1781
May1st to 15thNight
18%10%46%314446%35%
1516
16th to endNight
13%6%36%5%345%5%8%36%
1495
June1st to 15thNight
21%7%35%42435%6%33%
1440
16th to endNight
12%413435%46%10%41%
1440
July1st to 15thNight
11%5%25%5%35%5%6%8%40%
1440
16th to endNight
11%4245%35%45%8%43%
1514
August1st to 15thNight
11%6%26%5%25%5%5%7%42%
1579
16th to endNight
13%5%25%5%2435%7%44%
1910
September1st to 15thNight
16%5%25%5%34445%43%
1800
16th to endNight
14%5%24424346%46%
1831
October1st to 15thNight
19%8%35%5%23445%36%
1961
16th to endNight
20%12%37%5%3345%6%27%
2197
November1st to 15thNight
13%16%46%424345%33%
2277
16th to endNight
14%11%6%7%5%35%5%46%28%
2454
December1st to 15thNight
16%15%7%11%7%34445%18%
2520
16th to endNight
15%14%9%13%8%35%445%16%
2688

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
9%11%6%13%11%46%445%21%
1432
16th to endDay
8%12%8%13%10%5%6%34421%
1614
February1st to 15thDay
11%13%8%10%11%45%5%5%418%
1592
16th to endDay
12%11%6%12%9%35%45%5%24%
1580
March1st to 15thDay
14%14%5%9%6%35%446%25%
1824
16th to endDay
15%10%7%8%5%2335%5%31%
2216
April1st to 15thDay
15%14%5%7%5%23345%30%
2152
16th to endDay
15%12%36%424436%34%
2178
May1st to 15thDay
19%12%46%5%35%45%6%28%
2445
16th to endDay
15%8%36%7%35%5%6%7%30%
2618
June1st to 15thDay
21%8%36%5%345%5%9%26%
2520
16th to endDay
17%8%36%7%36%5%6%8%25%
2520
July1st to 15thDay
13%6%37%7%47%6%6%8%28%
2520
16th to endDay
13%5%36%6%46%6%6%9%30%
2654
August1st to 15thDay
14%9%47%7%46%6%6%7%27%
2364
16th to endDay
14%5%36%7%35%6%6%8%32%
2292
September1st to 15thDay
15%7%37%5%3445%8%34%
2160
16th to endDay
14%6%35%424446%43%
1875
October1st to 15thDay
18%10%45%6%33445%32%
1667
16th to endDay
19%16%46%6%2445%5%24%
1673
November1st to 15thDay
13%15%5%6%5%3345%431%
1581
16th to endDay
14%13%5%7%6%44446%27%
1506
December1st to 15thDay
14%16%8%12%7%35%335%20%
1440
16th to endDay
12%16%10%13%8%35%445%14%
1536
January1st to 15thNight
11%12%6%12%9%45%5%46%21%
2506
16th to endNight
10%12%7%12%9%45%45%6%22%
2610
February1st to 15thNight
10%13%8%12%9%46%6%4419%
2261
16th to endNight
11%11%6%10%9%46%445%24%
1893
March1st to 15thNight
14%10%6%11%9%3343426%
2133
16th to endNight
14%10%6%8%6%23336%33%
2007
April1st to 15thNight
13%14%5%8%5%34446%29%
1796
16th to endNight
16%11%445%24345%38%
1781
May1st to 15thNight
17%10%46%424447%34%
1516
16th to endNight
12%6%36%5%445%6%8%36%
1495
June1st to 15thNight
20%7%35%42435%7%33%
1440
16th to endNight
11%5%235%25%47%9%42%
1440
July1st to 15thNight
10%5%35%5%35%5%6%7%40%
1440
16th to endNight
11%4246%35%45%9%42%
1514
August1st to 15thNight
10%7%26%5%35%5%5%8%41%
1579
16th to endNight
11%5%36%5%3435%7%44%
1910
September1st to 15thNight
14%6%245%34445%44%
1800
16th to endNight
13%5%24424446%46%
1831
October1st to 15thNight
18%9%36%5%33445%36%
1961
16th to endNight
18%12%38%5%3445%6%26%
2197
November1st to 15thNight
12%15%47%424345%33%
2277
16th to endNight
14%11%6%7%6%45%5%5%5%28%
2454
December1st to 15thNight
15%14%7%12%8%34445%19%
2520
16th to endNight
14%14%7%14%9%44445%16%
2688

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
63%6%8%14%5%
1433
16th to endDay
65%6%9%12%5%
1614
February1st to 15thDay
68%5%7%11%6%
1595
16th to endDay
61%5%9%15%7%
1580
March1st to 15thDay
59%5%11%15%7%
1824
16th to endDay
53%5%8%15%13%2
2217
April1st to 15thDay
56%47%19%10%1
2152
16th to endDay
50%5%8%19%14%2
2178
May1st to 15thDay
55%7%6%19%9%1
2445
16th to endDay
51%8%13%17%9%
2622
June1st to 15thDay
54%7%13%15%8%
2520
16th to endDay
54%8%13%14%8%
2520
July1st to 15thDay
50%9%11%18%8%1
2371
16th to endDay
47%9%15%17%9%
2487
August1st to 15thDay
53%8%11%18%7%
2350
16th to endDay
45%8%11%22%11%
2292
September1st to 15thDay
47%5%12%20%12%1
2160
16th to endDay
41%5%9%23%18%1
1875
October1st to 15thDay
52%6%7%18%12%1
1667
16th to endDay
60%6%11%13%6%
1673
November1st to 15thDay
54%412%15%10%2
1581
16th to endDay
56%6%11%15%8%1
1506
December1st to 15thDay
67%5%10%11%4
1440
16th to endDay
71%5%9%9%4
1536
January1st to 15thNight
62%6%10%11%6%1
2506
16th to endNight
61%7%10%12%7%
2610
February1st to 15thNight
66%8%8%10%6%
2269
16th to endNight
61%5%9%14%8%1
1893
March1st to 15thNight
60%410%14%7%
2133
16th to endNight
53%410%16%12%2
2007
April1st to 15thNight
56%6%9%17%9%
1796
16th to endNight
47%6%9%20%14%1
1781
May1st to 15thNight
49%6%10%18%13%1
1516
16th to endNight
44%9%15%19%10%
1497
June1st to 15thNight
50%6%11%21%8%
1440
16th to endNight
35%8%19%25%9%
1440
July1st to 15thNight
38%9%15%24%10%1
1360
16th to endNight
37%7%16%25%11%1
1418
August1st to 15thNight
39%8%17%23%10%
1569
16th to endNight
38%6%13%28%12%
1910
September1st to 15thNight
41%6%13%24%13%
1800
16th to endNight
38%5%9%25%20%
1831
October1st to 15thNight
49%5%10%18%14%1
1961
16th to endNight
56%6%13%15%7%
2197
November1st to 15thNight
52%6%9%16%11%2
2277
16th to endNight
55%6%12%15%8%1
2454
December1st to 15thNight
67%6%11%10%4
2520
16th to endNight
69%6%9%10%4
2688

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
26%35%20%11%5%1
60
16th to endDay
32%32%24%9%1
77
February1st to 15thDay
33%37%23%3
109
16th to endDay
28%30%25%13%2
239
March1st to 15thDay
30%25%27%13%3
270
16th to endDay
26%25%24%12%8%2
288
April1st to 15thDay
30%25%22%12%7%1
270
16th to endDay
22%19%30%15%5%6%
270
May1st to 15thDay
33%15%22%14%7%5%
288
16th to endDay
17%15%34%18%10%3
331
June1st to 15thDay
26%15%28%18%9%1
315
16th to endDay
23%18%26%22%6%2
315
July1st to 15thDay
15%10%33%25%12%2
305
16th to endDay
16%7%32%27%13%3
326
August1st to 15thDay
15%12%24%21%17%8%
313
16th to endDay
15%7%22%23%16%12%
332
September1st to 15thDay
19%12%19%22%17%9%
315
16th to endDay
16%12%19%21%12%17%
266
October1st to 15thDay
26%11%21%20%15%5%
255
16th to endDay
30%21%25%17%5%
256
November1st to 15thDay
28%12%25%20%10%1
235
16th to endDay
30%25%22%12%7%1
126
December1st to 15thDay
35%28%18%11%6%
60
16th to endDay
34%32%31%1
64
January1st to 15thNight
28%25%28%13%3
720
16th to endNight
26%31%25%14%1
768
February1st to 15thNight
27%28%33%9%
704
16th to endNight
28%27%26%14%2
631
March1st to 15thNight
28%29%26%13%1
720
16th to endNight
26%26%21%18%6%
768
April1st to 15thNight
27%26%26%17%2
718
16th to endNight
28%18%24%17%10%
701
May1st to 15thNight
25%12%28%23%8%
436
16th to endNight
16%9%31%27%13%1
375
June1st to 15thNight
25%11%20%31%11%
360
16th to endNight
14%5%26%38%14%
360
July1st to 15thNight
13%7%24%36%17%
340
16th to endNight
11%222%43%18%1
376
August1st to 15thNight
13%5%25%33%19%2
498
16th to endNight
15%5%17%32%25%3
764
September1st to 15thNight
18%9%24%27%17%2
720
16th to endNight
17%9%21%23%20%6%
673
October1st to 15thNight
25%16%19%23%13%1
660
16th to endNight
29%21%22%22%3
704
November1st to 15thNight
24%21%26%19%6%1
700
16th to endNight
25%24%25%16%6%1
720
December1st to 15thNight
31%26%23%14%4
720
16th to endNight
32%29%22%12%2
768
Page generated at 2017-09-20 04:49:56. Version ac04

Copyright 2017 A. Danko


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