Sandy Pond Day Use Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sandy Pond Day Use Area clear sky chart from 2005-11-05 to 2017-10-16.

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%
15035
9%
47128
3%
14990
25%
14990
12%
36367

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
10%
750
10%
2643
1%
746
19%
746
8%
2058
January16th to endNight
12%
800
14%
2688
2%
800
24%
800
10%
2004
February1st to 15thNight
13%
734
10%
2366
2%
731
22%
731
13%
1757
February16th to endNight
12%
638
10%
1934
1%
638
20%
638
10%
1528
March1st to 15thNight
19%
672
12%
2112
4%
672
27%
672
11%
1608
March16th to endNight
15%
576
9%
2091
4%
576
22%
576
8%
1665
April1st to 15thNight
17%
539
12%
1724
6%
539
26%
539
11%
1332
April16th to endNight
17%
540
10%
1620
5%
540
23%
540
11%
1302
May1st to 15thNight
23%
540
6%
1551
2%
540
26%
540
10%
1264
May16th to endNight
19%
561
6%
1309
2%
560
21%
560
12%
1109
June1st to 15thNight
22%
540
3%
1260
1%
540
24%
540
13%
1057
June16th to endNight
21%
540
4%
1260
2%
540
23%
540
16%
1018
July1st to 15thNight
30%
510
6%
1190
4%
510
31%
510
23%
897
July16th to endNight
26%
565
6%
1363
2%
532
30%
532
16%
1072
August1st to 15thNight
28%
539
7%
1531
2%
535
33%
535
17%
1173
August16th to endNight
36%
573
11%
1719
8%
573
42%
573
19%
1228
September1st to 15thNight
28%
540
10%
1859
6%
540
35%
540
17%
1290
September16th to endNight
24%
538
13%
1980
9%
538
32%
538
15%
1375
October1st to 15thNight
21%
569
13%
2090
6%
569
32%
569
12%
1519
October16th to endNight
17%
741
9%
2299
3%
741
23%
741
11%
1834
November1st to 15thNight
18%
730
10%
2350
3%
730
23%
730
11%
1833
November16th to endNight
13%
750
10%
2609
2%
750
21%
750
9%
2056
December1st to 15thNight
12%
750
9%
2700
3%
750
20%
750
8%
2094
December16th to endNight
12%
800
7%
2880
1%
800
20%
800
7%
2294

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
24%13%47%5%34445%22%
48308
Night
23%12%46%5%34446%24%
47289
TransparencyDay
63%5%10%14%6%
47987
Night
60%5%11%15%6%
47128
SeeingDay
30%11%28%19%7%1
8292
Night
29%13%31%19%5%
15035

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
20%14%8%6%5%34345%21%
1295
16th to endDay
18%16%5%9%6%34345%21%
1536
February1st to 15thDay
19%13%47%6%25%45%5%23%
1493
16th to endDay
18%16%6%11%6%3443418%
1539
March1st to 15thDay
19%13%5%8%7%4434424%
1838
16th to endDay
24%21%5%8%6%2333415%
2130
April1st to 15thDay
21%17%5%5%6%35%446%20%
2222
16th to endDay
27%18%46%42223322%
2340
May1st to 15thDay
26%18%46%423346%19%
2400
16th to endDay
30%13%35%5%34346%20%
2805
June1st to 15thDay
32%13%47%5%24435%16%
2700
16th to endDay
27%10%46%5%24445%25%
2700
July1st to 15thDay
20%8%35%5%35%5%5%7%30%
2700
16th to endDay
24%8%48%6%35%5%5%6%20%
2707
August1st to 15thDay
26%9%37%6%3445%7%20%
2418
16th to endDay
24%8%37%6%345%5%8%23%
2483
September1st to 15thDay
26%9%36%5%24446%27%
2100
16th to endDay
19%9%46%434446%32%
1980
October1st to 15thDay
25%10%26%5%23335%29%
1869
16th to endDay
29%15%36%5%35%425%18%
1593
November1st to 15thDay
26%11%35%5%24436%26%
1506
16th to endDay
24%16%5%6%5%2423423%
1350
December1st to 15thDay
22%16%36%6%34445%21%
1260
16th to endDay
22%15%7%8%434435%20%
1344
January1st to 15thNight
21%15%47%5%35%5%35%22%
2643
16th to endNight
18%12%48%5%3445%6%26%
2688
February1st to 15thNight
19%12%5%7%6%24445%28%
2366
16th to endNight
19%15%6%9%5%34445%22%
1934
March1st to 15thNight
18%12%6%7%4345%45%25%
2099
16th to endNight
24%17%5%7%6%3333420%
2091
April1st to 15thNight
25%13%5%6%5%3433424%
1724
16th to endNight
28%17%25%5%2224323%
1620
May1st to 15thNight
28%13%46%5%2445%5%19%
1551
16th to endNight
31%13%25%5%34445%19%
1307
June1st to 15thNight
30%11%47%425%446%19%
1260
16th to endNight
27%10%47%5%24346%24%
1260
July1st to 15thNight
19%7%26%5%3445%9%31%
1260
16th to endNight
23%9%35%6%35%5%6%6%25%
1458
August1st to 15thNight
25%8%36%5%3445%6%26%
1542
16th to endNight
19%7%36%5%3445%7%32%
1719
September1st to 15thNight
23%7%26%5%23336%33%
1859
16th to endNight
19%8%26%5%345%47%32%
1980
October1st to 15thNight
23%9%46%435%346%28%
2090
16th to endNight
30%12%345%25%435%22%
2299
November1st to 15thNight
25%11%36%434446%24%
2350
16th to endNight
22%15%5%6%434446%20%
2609
December1st to 15thNight
24%14%47%5%34335%24%
2700
16th to endNight
24%14%6%7%6%24345%20%
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
64%5%10%11%6%
1296
16th to endDay
64%48%11%9%
1536
February1st to 15thDay
61%5%10%14%8%
1497
16th to endDay
70%38%11%5%
1539
March1st to 15thDay
63%48%14%8%
1848
16th to endDay
74%36%9%4
2130
April1st to 15thDay
65%5%9%13%5%
2222
16th to endDay
67%36%13%7%
2340
May1st to 15thDay
67%5%10%11%4
2400
16th to endDay
65%5%10%13%5%
2809
June1st to 15thDay
70%5%9%10%2
2700
16th to endDay
61%6%8%15%7%
2700
July1st to 15thDay
51%8%14%18%7%
2542
16th to endDay
62%7%12%12%4
2539
August1st to 15thDay
61%6%13%14%4
2404
16th to endDay
57%6%15%17%3
2483
September1st to 15thDay
55%6%11%19%6%
2100
16th to endDay
50%5%17%19%7%
1980
October1st to 15thDay
58%412%16%8%
1869
16th to endDay
69%5%5%12%6%
1593
November1st to 15thDay
60%5%13%13%5%
1506
16th to endDay
65%410%12%7%
1350
December1st to 15thDay
62%6%9%13%6%
1260
16th to endDay
67%29%13%5%
1344
January1st to 15thNight
64%49%14%6%1
2643
16th to endNight
58%5%10%15%9%
2688
February1st to 15thNight
58%412%17%6%
2366
16th to endNight
64%310%15%4
1934
March1st to 15thNight
59%6%10%15%8%
2112
16th to endNight
67%37%12%7%1
2091
April1st to 15thNight
63%38%15%8%
1724
16th to endNight
66%36%12%9%1
1620
May1st to 15thNight
66%5%10%12%4
1551
16th to endNight
66%6%10%9%5%
1309
June1st to 15thNight
66%5%12%10%5%
1260
16th to endNight
61%5%9%15%6%
1260
July1st to 15thNight
49%7%14%22%6%
1190
16th to endNight
57%7%14%16%3
1363
August1st to 15thNight
55%7%15%15%5%
1531
16th to endNight
49%7%16%21%5%
1719
September1st to 15thNight
51%5%15%20%7%
1859
16th to endNight
51%6%14%18%8%
1980
October1st to 15thNight
56%5%12%16%7%1
2090
16th to endNight
64%411%13%6%
2299
November1st to 15thNight
61%6%12%14%5%
2350
16th to endNight
64%5%10%12%6%
2609
December1st to 15thNight
63%49%15%6%
2700
16th to endNight
67%410%12%5%
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
25%20%38%12%2
240
16th to endDay
23%21%32%18%3
256
February1st to 15thDay
27%18%30%17%5%
236
16th to endDay
24%22%34%14%3
212
March1st to 15thDay
25%19%31%16%7%
240
16th to endDay
30%20%28%13%5%1
260
April1st to 15thDay
30%12%33%15%5%
339
16th to endDay
40%9%25%17%41
450
May1st to 15thDay
35%8%23%20%8%2
468
16th to endDay
35%10%27%18%6%1
519
June1st to 15thDay
41%8%20%21%8%1
495
16th to endDay
33%7%31%17%6%3
495
July1st to 15thDay
24%6%32%23%10%2
475
16th to endDay
28%6%25%28%10%
514
August1st to 15thDay
29%5%28%24%10%2
493
16th to endDay
28%326%26%12%2
523
September1st to 15thDay
34%9%24%23%7%
324
16th to endDay
21%14%29%27%5%1
269
October1st to 15thDay
28%12%32%16%8%1
270
16th to endDay
33%16%26%14%8%
243
November1st to 15thDay
29%14%29%15%9%
235
16th to endDay
32%17%33%14%1
240
December1st to 15thDay
29%18%34%13%4
240
16th to endDay
26%25%28%13%5%
256
January1st to 15thNight
29%18%33%14%2
750
16th to endNight
24%21%35%14%3
800
February1st to 15thNight
26%19%34%16%3
734
16th to endNight
27%16%36%14%41
638
March1st to 15thNight
23%19%30%19%6%
672
16th to endNight
32%15%28%19%3
576
April1st to 15thNight
28%14%32%19%4
539
16th to endNight
37%9%29%18%31
540
May1st to 15thNight
35%6%25%23%8%
540
16th to endNight
38%10%25%19%5%
561
June1st to 15thNight
36%6%25%24%6%
540
16th to endNight
33%7%30%21%7%
540
July1st to 15thNight
20%8%36%23%10%
510
16th to endNight
24%7%35%25%6%
565
August1st to 15thNight
29%5%31%22%9%
539
16th to endNight
23%6%27%33%8%1
573
September1st to 15thNight
27%8%32%24%7%
540
16th to endNight
25%9%35%25%4
538
October1st to 15thNight
29%10%32%19%6%
569
16th to endNight
36%13%28%18%3
741
November1st to 15thNight
29%15%30%17%5%
730
16th to endNight
31%17%32%15%2
750
December1st to 15thNight
30%18%34%12%4
750
16th to endNight
31%18%28%17%31
800
Page generated at 2017-10-17 18:05:23. Version ac04

Copyright 2017 A. Danko


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