Hampton Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hampton Mountain 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
46%
15507
23%
46936
14%
15464
54%
15464
27%
29269

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
24%
720
22%
2327
8%
716
41%
716
18%
1472
January16th to endNight
22%
768
24%
2465
9%
768
40%
768
20%
1564
February1st to 15thNight
27%
704
25%
2112
10%
701
43%
701
25%
1280
February16th to endNight
23%
631
24%
1893
8%
631
38%
631
23%
1193
March1st to 15thNight
29%
720
23%
2058
11%
720
40%
720
26%
1301
March16th to endNight
37%
768
21%
2112
11%
768
44%
768
29%
1336
April1st to 15thNight
40%
644
25%
1902
15%
644
51%
644
32%
1104
April16th to endNight
45%
540
25%
1689
16%
540
54%
540
30%
996
May1st to 15thNight
50%
540
20%
1620
11%
540
57%
540
27%
1038
May16th to endNight
59%
561
20%
1683
14%
561
64%
561
31%
1038
June1st to 15thNight
66%
540
15%
1620
13%
540
68%
540
28%
1040
June16th to endNight
73%
540
17%
1620
15%
540
74%
540
31%
998
July1st to 15thNight
68%
510
12%
1530
11%
510
68%
510
27%
1011
July16th to endNight
73%
564
16%
1595
14%
531
76%
531
28%
1039
August1st to 15thNight
69%
539
18%
1618
16%
536
70%
536
27%
1048
August16th to endNight
64%
573
18%
1910
19%
573
65%
573
22%
1285
September1st to 15thNight
60%
708
18%
1968
16%
708
62%
708
26%
1329
September16th to endNight
56%
665
23%
1837
17%
665
62%
665
29%
1197
October1st to 15thNight
52%
660
33%
1830
24%
660
60%
660
37%
1079
October16th to endNight
49%
704
33%
2112
24%
704
62%
704
36%
1176
November1st to 15thNight
48%
700
31%
2259
24%
700
60%
700
34%
1217
November16th to endNight
37%
720
27%
2340
17%
720
51%
720
26%
1371
December1st to 15thNight
32%
720
23%
2340
12%
720
45%
720
21%
1476
December16th to endNight
28%
768
20%
2496
12%
768
39%
768
17%
1681

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
14%5%245%35%5%5%7%40%
47831
Night
13%42442445%7%45%
47134
TransparencyDay
40%7%11%18%17%4
47532
Night
37%6%11%19%19%5%
46937
SeeingDay
17%6%19%22%21%12%
5382
Night
16%8%22%27%20%3
15509

By Month

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
19%6%25%323445%42%
1611
16th to endDay
18%5%24323345%44%
1758
February1st to 15thDay
18%424324346%43%
1750
16th to endDay
19%5%24323445%42%
1580
March1st to 15thDay
17%424424446%42%
1901
16th to endDay
16%5%25%424446%42%
2111
April1st to 15thDay
13%425%4345%6%6%43%
2055
16th to endDay
12%424434447%47%
2268
May1st to 15thDay
11%5%25%6%25%448%43%
2331
16th to endDay
11%426%5%35%6%6%8%39%
2431
June1st to 15thDay
9%5%25%6%47%7%8%10%33%
2340
16th to endDay
5%3135%47%7%9%12%39%
2340
July1st to 15thDay
11%425%6%5%7%8%8%10%29%
2340
16th to endDay
7%436%8%49%8%8%9%29%
2465
August1st to 15thDay
10%4246%47%7%8%10%32%
2328
16th to endDay
14%6%36%7%46%6%7%9%27%
2290
September1st to 15thDay
12%5%35%6%45%5%6%7%37%
1980
16th to endDay
18%5%14433447%41%
1829
October1st to 15thDay
14%31332334455%
1799
16th to endDay
12%42331333360%
1760
November1st to 15thDay
13%32331334455%
1596
16th to endDay
16%5%13323446%46%
1620
December1st to 15thDay
21%6%24324346%40%
1620
16th to endDay
25%7%24323345%36%
1728
January1st to 15thNight
19%425%313445%44%
2327
16th to endNight
17%6%34433345%43%
2465
February1st to 15thNight
15%5%24414346%48%
2103
16th to endNight
16%41442445%5%44%
1893
March1st to 15thNight
15%424415%446%45%
2058
16th to endNight
13%5%24424346%47%
2112
April1st to 15thNight
12%41322335%7%51%
1902
16th to endNight
9%5%25%5%2345%6%49%
1689
May1st to 15thNight
10%425%435%6%6%8%42%
1619
16th to endNight
8%425%4345%5%9%45%
1682
June1st to 15thNight
7%4246%45%5%8%11%39%
1620
16th to endNight
5%3145%46%5%7%11%43%
1620
July1st to 15thNight
8%325%6%46%6%7%10%36%
1620
16th to endNight
6%325%5%46%7%8%14%36%
1703
August1st to 15thNight
9%5%25%435%47%12%39%
1629
16th to endNight
12%5%25%6%35%6%6%9%35%
1910
September1st to 15thNight
11%5%26%5%35%6%6%8%39%
1968
16th to endNight
14%4144235%5%7%45%
1837
October1st to 15thNight
13%413213335%55%
1830
16th to endNight
10%31432332458%
2112
November1st to 15thNight
12%413213237%56%
2259
16th to endNight
15%5%23323345%50%
2340
December1st to 15thNight
17%6%25%333346%43%
2340
16th to endNight
23%6%35%423346%37%
2496

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
43%5%7%15%23%4
1612
16th to endDay
42%36%19%21%6%
1758
February1st to 15thDay
40%48%20%22%3
1752
16th to endDay
42%37%20%19%6%
1580
March1st to 15thDay
41%49%18%19%6%
1901
16th to endDay
42%411%21%16%3
2112
April1st to 15thDay
38%5%10%20%19%5%
2055
16th to endDay
35%6%10%20%21%5%
2268
May1st to 15thDay
38%6%12%19%18%3
2331
16th to endDay
38%10%13%20%14%2
2435
June1st to 15thDay
39%12%18%21%7%1
2340
16th to endDay
32%12%15%23%13%2
2340
July1st to 15thDay
43%12%18%16%6%1
2201
16th to endDay
43%13%16%16%7%1
2310
August1st to 15thDay
41%12%16%19%9%1
2315
16th to endDay
49%11%14%14%9%
2290
September1st to 15thDay
42%10%13%16%14%3
1980
16th to endDay
40%5%13%16%19%4
1829
October1st to 15thDay
31%5%9%17%27%9%
1799
16th to endDay
29%35%18%30%11%
1760
November1st to 15thDay
31%36%15%32%10%
1596
16th to endDay
38%47%15%26%7%
1620
December1st to 15thDay
44%5%8%18%16%7%
1620
16th to endDay
50%38%16%15%5%
1728
January1st to 15thNight
41%47%16%23%5%
2327
16th to endNight
43%36%18%22%6%
2465
February1st to 15thNight
38%28%20%21%8%
2112
16th to endNight
40%37%20%23%5%
1893
March1st to 15thNight
38%5%11%18%19%8%
2058
16th to endNight
37%5%10%24%19%3
2112
April1st to 15thNight
31%411%24%21%6%
1902
16th to endNight
33%6%9%22%20%7%
1689
May1st to 15thNight
36%8%13%20%18%2
1620
16th to endNight
33%8%14%26%13%3
1684
June1st to 15thNight
35%10%20%23%9%1
1620
16th to endNight
32%9%16%24%14%2
1620
July1st to 15thNight
38%9%22%19%8%1
1530
16th to endNight
34%12%20%21%9%2
1595
August1st to 15thNight
36%10%17%22%11%1
1618
16th to endNight
41%10%17%17%12%
1910
September1st to 15thNight
39%9%14%17%15%3
1968
16th to endNight
37%8%10%21%16%6%
1837
October1st to 15thNight
31%411%16%27%8%
1830
16th to endNight
30%25%18%30%12%
2112
November1st to 15thNight
29%35%17%30%12%
2259
16th to endNight
35%45%19%25%9%
2340
December1st to 15thNight
42%48%18%18%8%
2340
16th to endNight
48%48%15%17%5%
2496

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
25%14%37%16%5%
90
16th to endDay
22%25%38%11%2
96
February1st to 15thDay
21%28%35%14%
90
16th to endDay
32%18%35%11%2
81
March1st to 15thDay
20%16%31%21%7%1
191
16th to endDay
20%11%31%24%11%1
288
April1st to 15thDay
18%11%27%22%15%3
270
16th to endDay
17%6%24%25%21%4
270
May1st to 15thDay
16%7%30%18%13%13%
288
16th to endDay
15%6%14%27%21%14%
331
June1st to 15thDay
13%112%23%26%23%
315
16th to endDay
9%114%26%24%23%
315
July1st to 15thDay
10%110%24%30%21%
305
16th to endDay
6%11%19%37%25%
326
August1st to 15thDay
18%9%25%23%22%
313
16th to endDay
18%110%21%30%18%
332
September1st to 15thDay
15%411%23%28%16%
315
16th to endDay
22%115%26%23%11%
259
October1st to 15thDay
19%323%23%21%8%
255
16th to endDay
15%8%16%27%27%5%
272
November1st to 15thDay
28%13%22%14%18%2
104
16th to endDay
15%14%28%26%12%2
90
December1st to 15thDay
24%18%32%20%4
90
16th to endDay
37%14%28%16%21
96
January1st to 15thNight
26%17%26%22%6%
720
16th to endNight
22%17%34%23%2
768
February1st to 15thNight
20%16%31%26%4
704
16th to endNight
19%18%35%22%3
631
March1st to 15thNight
19%14%34%25%5%
720
16th to endNight
17%11%27%29%12%
768
April1st to 15thNight
16%12%28%26%15%
644
16th to endNight
13%7%26%32%18%1
540
May1st to 15thNight
14%6%24%30%22%2
540
16th to endNight
12%215%28%33%6%
563
June1st to 15thNight
9%113%32%32%10%
540
16th to endNight
6%10%34%36%11%
540
July1st to 15thNight
10%8%24%44%11%
510
16th to endNight
6%16%27%46%11%
564
August1st to 15thNight
13%17%26%39%10%
539
16th to endNight
14%18%25%40%9%
573
September1st to 15thNight
13%112%27%35%9%
708
16th to endNight
16%217%35%25%2
665
October1st to 15thNight
13%5%23%28%23%4
660
16th to endNight
12%8%24%29%22%3
704
November1st to 15thNight
15%8%23%29%21%2
700
16th to endNight
18%15%26%25%14%
720
December1st to 15thNight
20%14%27%25%10%1
720
16th to endNight
27%11%28%25%6%
768
Page generated at 2017-09-18 08:38:23. Version ac04

Copyright 2017 A. Danko


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