Minto-Brown Island Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Minto-Brown Island Park clear sky chart from 2005-11-05 to 2018-01-20.

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
46%
15197
13%
48530
12%
15170
49%
15170
19%
34428

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
31%
777
7%
2716
6%
776
33%
776
8%
2252
January16th to endNight
38%
788
11%
2632
11%
788
40%
788
12%
2029
February1st to 15thNight
36%
698
7%
2288
6%
698
37%
698
10%
1867
February16th to endNight
33%
632
10%
2011
8%
632
36%
632
12%
1581
March1st to 15thNight
33%
720
5%
2026
4%
720
34%
720
11%
1684
March16th to endNight
33%
768
6%
2091
4%
768
34%
768
11%
1758
April1st to 15thNight
37%
719
7%
1799
4%
719
38%
719
15%
1460
April16th to endNight
46%
598
11%
1678
7%
598
48%
598
19%
1242
May1st to 15thNight
47%
407
13%
1487
12%
407
53%
407
22%
940
May16th to endNight
48%
375
9%
1496
12%
374
51%
374
14%
1036
June1st to 15thNight
50%
360
9%
1440
12%
360
54%
360
17%
943
June16th to endNight
55%
360
13%
1440
18%
360
60%
360
24%
831
July1st to 15thNight
71%
340
19%
1360
26%
340
78%
340
46%
567
July16th to endNight
77%
387
28%
1427
34%
365
87%
365
62%
507
August1st to 15thNight
82%
538
26%
1611
24%
535
85%
535
58%
741
August16th to endNight
75%
654
34%
1800
23%
654
78%
654
56%
906
September1st to 15thNight
75%
720
29%
1800
18%
720
77%
720
59%
949
September16th to endNight
65%
716
25%
1980
21%
716
67%
716
36%
1200
October1st to 15thNight
54%
720
17%
2160
17%
720
56%
720
27%
1400
October16th to endNight
44%
768
14%
2313
14%
768
47%
768
19%
1673
November1st to 15thNight
35%
760
8%
2603
9%
760
36%
760
10%
2114
November16th to endNight
38%
780
6%
2730
6%
780
39%
780
11%
2139
December1st to 15thNight
38%
780
10%
2730
10%
780
39%
780
12%
2094
December16th to endNight
27%
832
5%
2912
5%
832
28%
832
6%
2515

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
17%8%47%6%34446%33%
49014
Night
18%8%36%5%34445%36%
48699
Cloud CoverDay
19%8%37%5%34445%33%
49014
Night
19%7%36%5%24445%35%
48703
TransparencyDay
52%6%11%16%10%2
48687
Night
50%6%11%17%10%2
48531
SeeingDay
22%8%20%25%17%4
6015
Night
22%5%16%31%20%1
15207

By Month

Percentage Cloud Cover NW (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
30%13%6%11%6%3432313%
1552
16th to endDay
25%10%49%7%45%5%36%18%
1692
February1st to 15thDay
29%11%5%9%7%35%44414%
1576
16th to endDay
25%12%6%9%7%35%33416%
1463
March1st to 15thDay
29%11%6%8%7%45%45%412%
1932
16th to endDay
26%12%5%9%7%45%345%14%
2133
April1st to 15thDay
21%13%5%8%7%45%45%6%16%
2149
16th to endDay
19%10%47%6%46%46%6%22%
2280
May1st to 15thDay
16%9%36%5%24347%34%
2463
16th to endDay
18%8%46%7%35%5%5%7%27%
2615
June1st to 15thDay
18%9%47%6%35%446%29%
2520
16th to endDay
10%7%36%5%35%45%6%41%
2520
July1st to 15thDay
4314323346%63%
2520
16th to endDay
6%213212235%68%
2644
August1st to 15thDay
231332335%7%61%
2340
16th to endDay
4314313347%61%
2402
September1st to 15thDay
4423212346%62%
2160
16th to endDay
13%7%35%6%2445%5%40%
1976
October1st to 15thDay
17%9%36%6%35%45%5%32%
1800
16th to endDay
20%11%5%9%6%34446%23%
1911
November1st to 15thDay
28%12%6%9%8%25%445%12%
1582
16th to endDay
25%11%5%10%7%45%44416%
1560
December1st to 15thDay
23%12%6%9%7%34335%17%
1560
16th to endDay
32%13%5%10%7%25%43410%
1664
January1st to 15thNight
28%11%5%8%5%35%435%17%
2716
16th to endNight
23%9%47%6%2445%6%24%
2632
February1st to 15thNight
23%11%48%7%45%445%20%
2276
16th to endNight
22%10%48%6%3444426%
2011
March1st to 15thNight
24%10%48%7%34445%20%
2026
16th to endNight
23%11%48%7%35%46%5%19%
2087
April1st to 15thNight
21%10%37%7%4345%7%25%
1799
16th to endNight
15%7%36%425%448%34%
1678
May1st to 15thNight
10%5%36%5%35%45%7%42%
1487
16th to endNight
14%8%26%5%245%6%8%34%
1496
June1st to 15thNight
15%6%35%5%3435%6%41%
1440
16th to endNight
7%6%35%423346%51%
1440
July1st to 15thNight
33221233472%
1440
16th to endNight
311123480%
1523
August1st to 15thNight
2211212347%71%
1620
16th to endNight
421221223471%
1800
September1st to 15thNight
3112222235%71%
1800
16th to endNight
9%41442435%7%52%
1980
October1st to 15thNight
13%5%25%5%24445%46%
2160
16th to endNight
19%8%36%5%2445%5%34%
2313
November1st to 15thNight
26%8%37%6%35%5%6%5%20%
2603
16th to endNight
24%9%37%6%35%445%25%
2730
December1st to 15thNight
24%10%47%6%34345%25%
2730
16th to endNight
27%13%5%9%8%3444315%
2912

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
32%12%6%11%6%3432313%
1552
16th to endDay
26%10%49%7%34445%18%
1692
February1st to 15thDay
30%11%5%9%8%34345%13%
1576
16th to endDay
26%11%5%9%7%44435%16%
1463
March1st to 15thDay
30%11%5%8%7%35%45%412%
1932
16th to endDay
28%11%5%8%6%45%5%4414%
2133
April1st to 15thDay
24%10%5%9%7%45%45%6%16%
2149
16th to endDay
21%8%47%6%35%5%5%7%23%
2280
May1st to 15thDay
19%7%36%5%34346%35%
2463
16th to endDay
19%7%46%5%35%5%5%6%28%
2615
June1st to 15thDay
19%8%47%5%245%46%30%
2520
16th to endDay
11%6%25%5%35%5%46%41%
2520
July1st to 15thDay
4313323346%63%
2520
16th to endDay
6%31221223468%
2644
August1st to 15thDay
3312423447%61%
2340
16th to endDay
5%413323347%61%
2402
September1st to 15thDay
5%413313246%62%
2160
16th to endDay
16%5%36%5%24445%40%
1976
October1st to 15thDay
18%8%46%6%34446%32%
1800
16th to endDay
21%11%49%7%24345%24%
1911
November1st to 15thDay
30%12%5%10%6%3344412%
1582
16th to endDay
26%11%412%7%3344416%
1560
December1st to 15thDay
26%10%6%10%7%33345%18%
1560
16th to endDay
34%12%49%7%35%4349%
1664
January1st to 15thNight
31%10%47%5%2444417%
2716
16th to endNight
26%8%47%5%24446%24%
2632
February1st to 15thNight
25%11%5%7%5%35%346%20%
2276
16th to endNight
24%10%37%6%35%445%25%
2011
March1st to 15thNight
26%11%47%5%35%445%20%
2026
16th to endNight
26%10%48%6%345%5%6%19%
2091
April1st to 15thNight
24%9%47%6%3445%6%24%
1799
16th to endNight
19%7%26%435%45%7%33%
1678
May1st to 15thNight
12%5%35%5%245%46%42%
1487
16th to endNight
18%7%345%245%7%8%32%
1496
June1st to 15thNight
16%5%46%425%336%40%
1440
16th to endNight
9%7%25%5%23436%49%
1440
July1st to 15thNight
3311312226%70%
1440
16th to endNight
3211235%78%
1523
August1st to 15thNight
132113246%70%
1620
16th to endNight
5%212211335%70%
1800
September1st to 15thNight
4312212235%71%
1800
16th to endNight
10%31442335%7%52%
1980
October1st to 15thNight
14%6%25%423446%44%
2160
16th to endNight
20%8%27%5%33445%34%
2313
November1st to 15thNight
30%7%36%5%345%5%6%19%
2603
16th to endNight
26%10%36%6%25%345%24%
2730
December1st to 15thNight
27%9%37%6%3434425%
2730
16th to endNight
29%13%5%9%6%3444415%
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
75%5%5%7%4
1552
16th to endDay
66%6%8%9%5%2
1692
February1st to 15thDay
73%6%7%7%3
1576
16th to endDay
70%7%6%8%6%
1463
March1st to 15thDay
74%5%9%7%3
1932
16th to endDay
72%7%10%7%2
2133
April1st to 15thDay
68%8%11%9%2
2149
16th to endDay
61%8%13%10%5%1
2280
May1st to 15thDay
50%5%13%19%10%
2463
16th to endDay
55%10%14%15%4
2619
June1st to 15thDay
55%7%15%16%4
2520
16th to endDay
41%8%17%22%7%2
2520
July1st to 15thDay
22%413%28%23%7%
2371
16th to endDay
19%310%27%31%7%
2478
August1st to 15thDay
20%6%16%31%19%5%
2324
16th to endDay
23%5%12%30%23%4
2402
September1st to 15thDay
22%313%25%23%11%
2160
16th to endDay
44%6%12%19%12%3
1976
October1st to 15thDay
52%5%11%16%10%3
1800
16th to endDay
62%6%9%10%10%1
1911
November1st to 15thDay
73%6%9%8%1
1582
16th to endDay
70%7%6%6%8%
1560
December1st to 15thDay
68%48%10%7%
1560
16th to endDay
77%6%8%43
1664
January1st to 15thNight
70%5%8%8%5%1
2716
16th to endNight
60%6%8%11%9%3
2632
February1st to 15thNight
65%6%10%11%4
2288
16th to endNight
62%6%11%10%7%1
2011
March1st to 15thNight
65%7%9%12%4
2026
16th to endNight
65%9%11%10%3
2091
April1st to 15thNight
60%8%15%10%5%
1799
16th to endNight
51%8%15%17%5%1
1678
May1st to 15thNight
42%6%15%23%8%3
1488
16th to endNight
48%10%16%18%5%1
1496
June1st to 15thNight
45%8%16%22%6%
1440
16th to endNight
36%7%17%27%8%2
1440
July1st to 15thNight
18%413%30%25%8%
1360
16th to endNight
10%212%30%33%10%
1427
August1st to 15thNight
14%415%38%19%6%
1611
16th to endNight
17%411%37%21%7%
1800
September1st to 15thNight
17%413%27%23%13%
1800
16th to endNight
31%6%15%23%15%7%
1980
October1st to 15thNight
40%6%10%23%15%4
2160
16th to endNight
50%7%11%13%14%1
2313
November1st to 15thNight
64%8%9%12%5%
2603
16th to endNight
62%6%9%8%10%1
2730
December1st to 15thNight
61%5%10%13%9%
2730
16th to endNight
73%6%7%8%3
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
40%215%25%13%3
90
16th to endDay
31%8%17%19%17%4
195
February1st to 15thDay
40%9%16%19%12%2
236
16th to endDay
33%11%24%19%8%2
219
March1st to 15thDay
43%15%19%16%31
270
16th to endDay
36%12%26%16%6%1
288
April1st to 15thDay
26%15%24%18%9%6%
269
16th to endDay
28%16%25%14%11%4
270
May1st to 15thDay
25%13%24%22%12%2
288
16th to endDay
20%9%15%24%23%7%
330
June1st to 15thDay
20%8%23%26%18%2
315
16th to endDay
10%8%26%33%20%1
315
July1st to 15thDay
5%5%17%39%23%7%
305
16th to endDay
5%220%40%25%4
327
August1st to 15thDay
5%316%36%27%9%
315
16th to endDay
36%17%30%33%8%
332
September1st to 15thDay
8%5%21%30%27%6%
315
16th to endDay
17%8%20%30%20%3
315
October1st to 15thDay
24%8%22%26%15%2
315
16th to endDay
31%6%19%21%15%5%
327
November1st to 15thDay
38%14%23%17%31
103
16th to endDay
40%11%22%12%12%2
90
December1st to 15thDay
36%10%20%16%11%5%
90
16th to endDay
40%6%16%16%17%2
96
January1st to 15thNight
36%5%14%23%17%2
780
16th to endNight
28%6%15%24%21%3
788
February1st to 15thNight
29%7%16%25%19%1
704
16th to endNight
27%9%22%23%16%
632
March1st to 15thNight
30%10%19%25%12%
720
16th to endNight
28%8%20%27%13%1
768
April1st to 15thNight
27%8%18%26%18%
719
16th to endNight
21%5%19%32%20%1
598
May1st to 15thNight
13%5%24%37%18%
408
16th to endNight
22%414%33%22%1
375
June1st to 15thNight
18%318%40%18%1
360
16th to endNight
12%321%47%14%
360
July1st to 15thNight
4216%51%24%
340
16th to endNight
3115%55%23%
387
August1st to 15thNight
47%43%39%5%
538
16th to endNight
5%112%43%33%1
654
September1st to 15thNight
6%113%42%31%5%
720
16th to endNight
12%312%37%31%3
716
October1st to 15thNight
17%318%35%22%2
720
16th to endNight
25%5%15%27%22%3
768
November1st to 15thNight
32%6%16%30%12%
760
16th to endNight
30%7%16%26%16%2
780
December1st to 15thNight
30%7%14%27%18%1
780
16th to endNight
35%9%17%22%14%1
832
Page generated at 2018-01-21 09:19:30. Version ac04

Copyright 2018 A. Danko


Minto-Brown Island Park Clear Sky Chart |Charts Home