Butter Pot Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Butter Pot Park clear sky chart from 2005-11-05 to 2017-09-17.

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
19%
14874
8%
46784
3%
14829
24%
14829
10%
37756

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
9%
750
7%
2637
1%
746
15%
746
5%
2221
January16th to endNight
11%
800
9%
2688
2%
800
18%
800
7%
2179
February1st to 15thNight
11%
734
6%
2311
1%
731
16%
731
7%
1912
February16th to endNight
9%
640
8%
1949
1%
640
15%
640
7%
1645
March1st to 15thNight
16%
645
9%
2085
4%
645
22%
645
9%
1675
March16th to endNight
13%
576
7%
2112
3%
576
19%
576
6%
1777
April1st to 15thNight
19%
539
9%
1727
5%
539
26%
539
9%
1397
April16th to endNight
16%
540
9%
1620
4%
540
23%
540
10%
1316
May1st to 15thNight
25%
540
6%
1607
2%
540
27%
540
10%
1336
May16th to endNight
22%
561
7%
1317
1%
560
25%
560
12%
1112
June1st to 15thNight
22%
540
3%
1260
1%
540
24%
540
9%
1094
June16th to endNight
25%
540
6%
1260
2%
540
27%
540
17%
1013
July1st to 15thNight
32%
510
7%
1190
2%
510
34%
510
20%
926
July16th to endNight
30%
565
6%
1366
2%
532
31%
532
13%
1121
August1st to 15thNight
30%
539
7%
1585
3%
535
33%
535
13%
1247
August16th to endNight
34%
573
10%
1719
7%
573
39%
573
17%
1271
September1st to 15thNight
31%
540
9%
1863
7%
540
36%
540
14%
1363
September16th to endNight
31%
499
14%
1835
10%
499
39%
499
16%
1276
October1st to 15thNight
24%
516
13%
1930
6%
516
33%
516
12%
1428
October16th to endNight
16%
697
9%
2249
3%
697
22%
697
7%
1864
November1st to 15thNight
21%
730
7%
2356
2%
730
25%
730
11%
1873
November16th to endNight
15%
750
9%
2538
2%
750
22%
750
9%
2052
December1st to 15thNight
13%
750
7%
2700
2%
750
19%
750
6%
2193
December16th to endNight
13%
800
5%
2880
2%
800
17%
800
5%
2465

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
20%13%5%8%6%35%446%20%
47998
Night
20%13%5%8%6%35%45%6%19%
46946
TransparencyDay
65%6%9%12%5%
47678
Night
64%6%9%12%5%
46784
SeeingDay
28%12%29%20%8%1
8227
Night
27%13%32%20%6%
14874

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
18%16%8%11%7%5%7%5%45%11%
1298
16th to endDay
18%17%7%11%7%4445%7%11%
1536
February1st to 15thDay
18%14%6%12%9%45%5%45%12%
1548
16th to endDay
18%16%9%11%7%35%5%3412%
1524
March1st to 15thDay
15%14%7%10%9%5%5%445%16%
1864
16th to endDay
22%18%8%9%7%2434412%
2112
April1st to 15thDay
16%16%7%9%8%35%34418%
2217
16th to endDay
25%16%5%6%5%23435%20%
2340
May1st to 15thDay
23%16%5%7%5%34446%19%
2345
16th to endDay
21%13%47%6%45%45%7%18%
2795
June1st to 15thDay
26%14%47%6%34435%17%
2700
16th to endDay
22%10%36%6%3446%7%24%
2700
July1st to 15thDay
15%7%36%6%35%6%6%7%30%
2700
16th to endDay
18%8%36%7%47%5%6%7%23%
2704
August1st to 15thDay
25%9%36%5%45%5%47%21%
2362
16th to endDay
18%9%38%7%445%5%8%23%
2483
September1st to 15thDay
21%8%46%5%2445%7%29%
2094
16th to endDay
15%8%37%5%3436%8%33%
1831
October1st to 15thDay
24%9%37%6%345%46%25%
1700
16th to endDay
25%17%36%6%445%45%16%
1622
November1st to 15thDay
16%14%5%6%7%45%448%21%
1500
16th to endDay
20%18%6%8%6%25%45%5%15%
1419
December1st to 15thDay
18%15%6%9%6%35%446%18%
1260
16th to endDay
20%19%7%10%8%3444412%
1344
January1st to 15thNight
19%16%8%11%7%35%445%12%
2637
16th to endNight
17%13%8%10%9%45%5%46%15%
2688
February1st to 15thNight
18%11%6%11%9%45%5%5%6%15%
2311
16th to endNight
17%15%9%12%7%45%34415%
1949
March1st to 15thNight
14%12%7%11%8%5%6%5%5%6%17%
2073
16th to endNight
23%15%7%10%6%35%5%3413%
2112
April1st to 15thNight
21%13%6%8%6%44445%18%
1727
16th to endNight
24%17%5%8%5%2333420%
1620
May1st to 15thNight
26%14%46%5%26%446%17%
1607
16th to endNight
25%11%45%6%35%45%7%19%
1315
June1st to 15thNight
26%12%36%6%36%45%6%18%
1260
16th to endNight
22%10%37%5%3446%9%22%
1260
July1st to 15thNight
16%7%25%7%45%6%7%10%25%
1260
16th to endNight
21%8%36%6%46%7%5%8%21%
1461
August1st to 15thNight
24%9%35%6%3445%8%22%
1596
16th to endNight
20%7%25%5%25%5%6%9%28%
1719
September1st to 15thNight
21%7%35%5%45%5%5%6%28%
1863
16th to endNight
17%8%46%5%2435%9%31%
1835
October1st to 15thNight
22%10%37%6%35%446%25%
1930
16th to endNight
26%15%37%6%35%44416%
2249
November1st to 15thNight
19%12%5%8%6%25%5%47%21%
2356
16th to endNight
18%15%5%9%6%35%5%5%6%17%
2538
December1st to 15thNight
18%13%6%10%7%35%45%5%18%
2700
16th to endNight
21%19%8%9%7%35%44312%
2880

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
72%6%7%8%4
1299
16th to endDay
71%38%8%7%
1536
February1st to 15thDay
70%7%8%8%5%
1552
16th to endDay
73%49%5%5%
1524
March1st to 15thDay
69%6%7%11%4
1875
16th to endDay
76%36%8%3
2112
April1st to 15thDay
69%5%7%11%5%
2217
16th to endDay
68%47%9%9%
2340
May1st to 15thDay
66%6%8%12%4
2345
16th to endDay
64%6%10%12%6%
2799
June1st to 15thDay
71%5%8%10%3
2700
16th to endDay
61%6%9%15%6%
2700
July1st to 15thDay
50%9%12%19%8%
2542
16th to endDay
59%8%12%15%4
2536
August1st to 15thDay
62%6%10%14%5%
2348
16th to endDay
58%7%12%16%3
2483
September1st to 15thDay
54%5%10%20%8%
2094
16th to endDay
50%5%12%20%10%
1831
October1st to 15thDay
60%6%11%13%6%
1700
16th to endDay
70%5%7%10%6%
1622
November1st to 15thDay
62%6%13%13%3
1500
16th to endDay
72%5%8%9%3
1419
December1st to 15thDay
66%7%8%11%6%
1260
16th to endDay
73%5%7%8%4
1344
January1st to 15thNight
71%6%8%7%5%
2637
16th to endNight
66%6%10%8%7%
2688
February1st to 15thNight
66%8%10%10%4
2311
16th to endNight
69%6%8%11%3
1949
March1st to 15thNight
62%8%10%11%6%
2085
16th to endNight
73%47%7%6%
2112
April1st to 15thNight
65%6%8%12%6%
1727
16th to endNight
68%36%10%9%1
1620
May1st to 15thNight
68%6%7%13%3
1607
16th to endNight
65%6%8%12%5%
1317
June1st to 15thNight
69%7%8%9%4
1260
16th to endNight
60%5%12%14%6%
1260
July1st to 15thNight
52%8%13%17%7%
1190
16th to endNight
61%9%11%15%2
1366
August1st to 15thNight
60%7%12%14%5%
1585
16th to endNight
51%8%14%19%5%
1719
September1st to 15thNight
55%6%11%18%7%
1863
16th to endNight
51%5%11%20%10%
1835
October1st to 15thNight
58%5%12%16%6%
1930
16th to endNight
69%5%7%11%5%
2249
November1st to 15thNight
62%6%13%10%5%
2356
16th to endNight
66%5%11%10%5%
2538
December1st to 15thNight
67%6%7%12%6%
2700
16th to endNight
73%5%7%8%4
2880

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
23%23%35%13%2
240
16th to endDay
25%17%37%14%21
256
February1st to 15thDay
26%19%30%19%4
236
16th to endDay
24%23%32%16%3
212
March1st to 15thDay
24%19%35%14%5%1
240
16th to endDay
29%21%30%11%5%1
256
April1st to 15thDay
23%19%28%16%9%1
352
16th to endDay
34%12%27%18%6%1
450
May1st to 15thDay
31%8%26%19%11%2
468
16th to endDay
30%10%32%19%6%1
519
June1st to 15thDay
37%7%27%19%7%1
495
16th to endDay
30%7%31%20%7%2
495
July1st to 15thDay
21%7%35%25%9%1
475
16th to endDay
26%6%25%27%13%1
514
August1st to 15thDay
30%426%27%8%2
493
16th to endDay
26%5%24%28%13%1
523
September1st to 15thDay
28%6%31%22%10%2
339
16th to endDay
22%7%31%27%9%1
228
October1st to 15thDay
28%10%29%20%8%2
225
16th to endDay
29%19%28%16%5%1
240
November1st to 15thDay
24%17%30%16%10%1
235
16th to endDay
28%17%32%16%4
240
December1st to 15thDay
25%22%29%15%7%
240
16th to endDay
32%23%25%14%3
256
January1st to 15thNight
28%18%33%15%2
750
16th to endNight
24%22%34%15%3
800
February1st to 15thNight
23%20%35%17%2
734
16th to endNight
26%17%36%15%5%
640
March1st to 15thNight
22%18%33%19%6%
645
16th to endNight
28%16%33%18%2
576
April1st to 15thNight
28%15%28%19%6%
539
16th to endNight
31%12%32%15%6%
540
May1st to 15thNight
33%5%27%22%9%
540
16th to endNight
29%11%30%22%5%1
561
June1st to 15thNight
32%7%29%20%8%
540
16th to endNight
27%7%32%22%8%
540
July1st to 15thNight
20%6%36%27%8%
510
16th to endNight
26%434%26%8%
565
August1st to 15thNight
30%329%27%8%1
539
16th to endNight
23%5%30%30%10%
573
September1st to 15thNight
22%7%34%26%7%1
540
16th to endNight
24%6%32%28%8%
499
October1st to 15thNight
27%12%29%21%7%1
516
16th to endNight
34%13%29%17%4
697
November1st to 15thNight
25%14%33%18%7%
730
16th to endNight
25%18%33%18%3
750
December1st to 15thNight
26%21%32%13%5%
750
16th to endNight
29%18%31%16%3
800
Page generated at 2017-09-18 10:08:21. Version ac04

Copyright 2017 A. Danko


Butter Pot Park Clear Sky Chart | Charts Home