Milton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Milton clear sky chart from 2005-11-05 to 2017-09-22.

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
41%
15252
20%
46919
12%
15216
50%
15216
25%
29721

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
27%
719
21%
2497
9%
716
43%
716
20%
1535
January16th to endNight
22%
768
22%
2496
7%
768
40%
768
22%
1563
February1st to 15thNight
24%
703
20%
2240
8%
701
40%
701
22%
1409
February16th to endNight
23%
631
27%
1893
10%
631
45%
631
24%
1169
March1st to 15thNight
29%
720
20%
2088
10%
720
41%
720
25%
1332
March16th to endNight
30%
768
20%
2031
9%
768
39%
768
24%
1382
April1st to 15thNight
34%
718
19%
1796
6%
718
41%
718
31%
1191
April16th to endNight
45%
720
18%
1800
9%
720
47%
720
30%
1224
May1st to 15thNight
42%
577
16%
1657
9%
577
47%
577
23%
1145
May16th to endNight
56%
374
15%
1497
15%
374
60%
374
19%
940
June1st to 15thNight
58%
360
16%
1440
17%
360
63%
360
22%
873
June16th to endNight
63%
360
14%
1440
18%
360
64%
360
22%
858
July1st to 15thNight
66%
340
13%
1360
17%
340
67%
340
20%
842
July16th to endNight
68%
448
15%
1484
16%
420
71%
420
25%
894
August1st to 15thNight
69%
605
16%
1675
12%
602
69%
602
32%
1053
August16th to endNight
66%
764
18%
1910
11%
764
67%
764
34%
1259
September1st to 15thNight
59%
720
23%
1800
15%
720
61%
720
33%
1190
September16th to endNight
54%
685
19%
1849
16%
685
56%
685
28%
1235
October1st to 15thNight
49%
660
24%
1974
22%
660
55%
660
27%
1253
October16th to endNight
38%
704
26%
2128
16%
704
51%
704
29%
1285
November1st to 15thNight
35%
700
22%
2277
13%
700
49%
700
25%
1396
November16th to endNight
34%
720
22%
2379
13%
720
47%
720
22%
1468
December1st to 15thNight
28%
720
19%
2520
9%
720
41%
720
19%
1582
December16th to endNight
24%
768
22%
2688
9%
768
42%
768
21%
1643

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
13%5%2442445%7%43%
47956
Night
14%5%25%42445%7%44%
47096
Cloud CoverDay
13%5%2442445%7%43%
47965
Night
14%5%2442445%7%44%
47102
TransparencyDay
38%6%12%23%15%2
47651
Night
39%5%11%22%16%2
46919
SeeingDay
16%5%22%29%20%5%
5830
Night
17%7%26%30%15%1
15255

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
14%7%2442435%6%44%
1438
16th to endDay
17%6%23414446%44%
1728
February1st to 15thDay
14%7%2442445%6%42%
1621
16th to endDay
13%7%35%334446%43%
1580
March1st to 15thDay
16%5%2442345%6%44%
1859
16th to endDay
16%6%24425%336%43%
2192
April1st to 15thDay
13%6%2432345%7%47%
2152
16th to endDay
14%5%145%2445%6%45%
2160
May1st to 15thDay
14%5%25%42446%8%41%
2303
16th to endDay
12%5%144345%6%8%42%
2618
June1st to 15thDay
13%424435%5%6%9%41%
2520
16th to endDay
9%414425%6%7%11%41%
2520
July1st to 15thDay
9%425%435%5%7%10%41%
2520
16th to endDay
7%4245%47%6%8%12%36%
2579
August1st to 15thDay
10%5%25%5%345%7%9%39%
2260
16th to endDay
9%4245%45%6%6%8%43%
2292
September1st to 15thDay
12%4245%3446%7%43%
2160
16th to endDay
15%6%25%435%5%46%39%
1923
October1st to 15thDay
17%424433346%44%
1653
16th to endDay
15%5%14313346%49%
1743
November1st to 15thDay
17%5%2322335%6%46%
1581
16th to endDay
14%5%14424447%47%
1578
December1st to 15thDay
13%5%36%4245%5%6%43%
1440
16th to endDay
18%7%24423346%42%
1536
January1st to 15thNight
15%5%3442445%6%43%
2497
16th to endNight
15%7%34423445%44%
2496
February1st to 15thNight
15%6%25%433345%44%
2239
16th to endNight
15%5%24323346%47%
1893
March1st to 15thNight
16%5%24323346%45%
2075
16th to endNight
18%7%34423346%42%
2031
April1st to 15thNight
15%5%26%32435%6%45%
1796
16th to endNight
17%425%424346%43%
1800
May1st to 15thNight
15%8%25%4335%5%6%38%
1657
16th to endNight
11%6%35%6%35%448%40%
1495
June1st to 15thNight
12%5%235%25%45%8%44%
1440
16th to endNight
8%336%5%46%5%5%10%40%
1440
July1st to 15thNight
7%425%6%35%6%7%9%39%
1440
16th to endNight
5%3347%36%6%6%10%40%
1586
August1st to 15thNight
6%416%5%35%5%6%9%43%
1686
16th to endNight
9%5%245%3446%10%43%
1910
September1st to 15thNight
14%5%2442445%7%45%
1800
16th to endNight
16%5%144236%5%7%41%
1849
October1st to 15thNight
16%5%24423446%45%
1974
16th to endNight
15%424323346%49%
2128
November1st to 15thNight
15%6%24313335%49%
2277
16th to endNight
14%5%25%42445%6%44%
2379
December1st to 15thNight
17%6%3442445%6%41%
2520
16th to endNight
17%5%25%32335%6%44%
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
14%7%24325%446%44%
1438
16th to endDay
17%6%245%24346%43%
1728
February1st to 15thDay
15%6%35%42346%6%42%
1621
16th to endDay
13%6%35%4245%45%43%
1580
March1st to 15thDay
16%425%42345%6%44%
1869
16th to endDay
16%6%24425%335%44%
2191
April1st to 15thDay
14%5%2332335%6%47%
2152
16th to endDay
14%5%245%14346%45%
2160
May1st to 15thDay
16%42443445%8%41%
2303
16th to endDay
13%5%244345%5%7%43%
2618
June1st to 15thDay
14%424326%5%6%9%40%
2520
16th to endDay
10%424435%5%7%10%42%
2520
July1st to 15thDay
9%425%4345%6%10%42%
2520
16th to endDay
7%325%5%47%7%8%12%36%
2579
August1st to 15thDay
10%5%35%5%446%6%8%39%
2260
16th to endDay
9%3245%35%6%6%7%43%
2292
September1st to 15thDay
12%425%43445%8%44%
2160
16th to endDay
15%6%26%5%345%46%38%
1923
October1st to 15thDay
16%5%24434445%44%
1653
16th to endDay
15%424413246%50%
1743
November1st to 15thDay
17%5%1331335%6%46%
1581
16th to endDay
14%324324448%46%
1578
December1st to 15thDay
13%6%35%42436%7%42%
1440
16th to endDay
18%6%44423246%42%
1536
January1st to 15thNight
15%5%3443345%6%43%
2497
16th to endNight
16%6%24423445%44%
2496
February1st to 15thNight
15%6%25%423345%45%
2232
16th to endNight
15%5%23323446%47%
1893
March1st to 15thNight
16%6%24323346%45%
2088
16th to endNight
18%8%35%324345%42%
2031
April1st to 15thNight
15%425%42335%7%44%
1796
16th to endNight
17%425%335%347%42%
1800
May1st to 15thNight
16%7%445%25%45%6%38%
1657
16th to endNight
12%6%345%36%447%42%
1495
June1st to 15thNight
12%6%244245%48%44%
1440
16th to endNight
8%336%5%45%6%6%9%40%
1440
July1st to 15thNight
7%5%26%6%35%6%5%10%40%
1440
16th to endNight
6%3347%37%6%6%11%40%
1586
August1st to 15thNight
6%425%5%445%6%9%43%
1686
16th to endNight
9%5%25%425%5%5%9%44%
1910
September1st to 15thNight
13%5%25%42335%6%45%
1800
16th to endNight
16%5%144245%5%8%40%
1849
October1st to 15thNight
16%5%24423435%46%
1974
16th to endNight
16%424312446%48%
2128
November1st to 15thNight
15%5%24323335%49%
2277
16th to endNight
14%5%25%42445%6%44%
2379
December1st to 15thNight
16%7%25%42445%6%41%
2520
16th to endNight
18%5%25%42335%5%44%
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
39%6%13%21%15%3
1439
16th to endDay
42%410%25%15%2
1728
February1st to 15thDay
41%412%24%14%2
1624
16th to endDay
41%5%11%25%15%2
1580
March1st to 15thDay
39%5%12%23%16%2
1869
16th to endDay
42%6%7%23%16%2
2192
April1st to 15thDay
36%5%11%24%17%4
2152
16th to endDay
38%5%11%17%20%6%
2160
May1st to 15thDay
39%7%15%21%14%1
2303
16th to endDay
36%7%14%25%12%1
2622
June1st to 15thDay
37%9%13%24%13%1
2520
16th to endDay
33%10%15%21%17%1
2520
July1st to 15thDay
35%8%14%23%15%2
2371
16th to endDay
33%10%16%23%13%1
2418
August1st to 15thDay
38%7%13%24%14%1
2247
16th to endDay
34%9%12%21%17%3
2292
September1st to 15thDay
36%7%12%22%18%2
2160
16th to endDay
44%6%8%17%20%1
1923
October1st to 15thDay
40%6%10%24%14%3
1653
16th to endDay
35%48%27%21%2
1743
November1st to 15thDay
38%5%12%23%17%2
1581
16th to endDay
36%5%11%26%17%2
1578
December1st to 15thDay
40%5%15%22%12%3
1440
16th to endDay
44%312%25%13%1
1536
January1st to 15thNight
41%411%21%18%2
2497
16th to endNight
41%410%26%14%2
2496
February1st to 15thNight
41%39%26%15%2
2240
16th to endNight
37%49%25%20%2
1893
March1st to 15thNight
40%411%25%15%2
2088
16th to endNight
44%49%19%18%3
2031
April1st to 15thNight
39%5%10%21%19%4
1796
16th to endNight
41%5%10%17%19%5%
1800
May1st to 15thNight
45%6%10%20%14%2
1657
16th to endNight
41%8%14%18%14%1
1497
June1st to 15thNight
37%9%12%22%17%1
1440
16th to endNight
37%8%14%21%15%2
1440
July1st to 15thNight
39%10%15%19%13%2
1360
16th to endNight
34%10%16%24%12%1
1484
August1st to 15thNight
34%7%17%20%18%
1675
16th to endNight
34%8%13%20%20%2
1910
September1st to 15thNight
38%5%12%22%17%3
1800
16th to endNight
40%7%11%19%18%2
1849
October1st to 15thNight
40%5%9%23%17%2
1974
16th to endNight
36%410%25%19%3
2128
November1st to 15thNight
39%410%21%18%6%
2277
16th to endNight
40%410%23%16%3
2379
December1st to 15thNight
43%5%12%23%12%2
2520
16th to endNight
41%414%22%14%2
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
16%13%37%26%41
61
16th to endDay
22%12%41%16%6%
96
February1st to 15thDay
24%18%33%19%3
137
16th to endDay
15%13%39%27%4
239
March1st to 15thDay
21%11%29%31%6%
270
16th to endDay
18%8%38%26%43
288
April1st to 15thDay
17%9%28%32%10%2
270
16th to endDay
20%7%19%34%15%2
270
May1st to 15thDay
25%7%28%23%12%2
288
16th to endDay
16%20%26%27%8%
331
June1st to 15thDay
20%118%26%26%7%
315
16th to endDay
14%115%40%23%4
315
July1st to 15thDay
11%10%37%32%6%
305
16th to endDay
7%17%35%35%12%
326
August1st to 15thDay
12%10%31%33%10%
313
16th to endDay
7%9%30%39%12%
332
September1st to 15thDay
13%20%27%22%14%
315
16th to endDay
26%211%27%21%10%
278
October1st to 15thDay
19%318%30%20%7%
255
16th to endDay
14%7%32%23%20%1
269
November1st to 15thDay
17%8%27%24%18%2
235
16th to endDay
12%16%32%21%16%1
198
December1st to 15thDay
15%16%23%33%11%
60
16th to endDay
32%9%35%17%4
64
January1st to 15thNight
17%14%36%25%5%
720
16th to endNight
20%13%39%23%2
768
February1st to 15thNight
19%13%37%28%1
704
16th to endNight
18%16%37%24%3
631
March1st to 15thNight
19%11%35%26%7%
720
16th to endNight
22%8%33%24%8%2
768
April1st to 15thNight
18%5%36%31%7%
718
16th to endNight
20%424%37%11%1
720
May1st to 15thNight
20%5%26%34%12%1
577
16th to endNight
16%216%38%23%2
375
June1st to 15thNight
13%118%39%25%1
360
16th to endNight
10%112%45%27%2
360
July1st to 15thNight
8%113%43%30%2
340
16th to endNight
5%210%36%40%4
448
August1st to 15thNight
10%7%44%34%2
605
16th to endNight
11%110%36%34%5%
764
September1st to 15thNight
17%113%31%32%4
720
16th to endNight
18%216%29%27%4
685
October1st to 15thNight
19%5%17%34%20%2
660
16th to endNight
18%8%30%25%15%
704
November1st to 15thNight
18%9%30%25%14%2
700
16th to endNight
15%14%30%28%10%1
720
December1st to 15thNight
21%10%35%19%10%1
720
16th to endNight
20%11%39%25%3
768
Page generated at 2017-09-23 06:43:44. Version ac04

Copyright 2017 A. Danko


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