Sassafras Ridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sassafras Ridge clear sky chart from 2005-11-05 to 2018-02-14.

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
40%
16089
20%
48802
13%
16046
47%
16046
21%
31880

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
22%
780
18%
2522
10%
776
33%
776
15%
1742
January16th to endNight
23%
832
20%
2697
11%
832
34%
832
16%
1849
February1st to 15thNight
23%
760
19%
2280
9%
757
33%
757
17%
1552
February16th to endNight
18%
631
19%
1893
7%
631
29%
631
14%
1324
March1st to 15thNight
23%
720
19%
2063
10%
720
31%
720
17%
1421
March16th to endNight
26%
768
16%
2112
9%
768
31%
768
20%
1449
April1st to 15thNight
32%
632
22%
1890
12%
632
42%
632
23%
1139
April16th to endNight
37%
540
21%
1676
12%
540
47%
540
23%
1031
May1st to 15thNight
37%
540
15%
1620
7%
540
44%
540
20%
1079
May16th to endNight
47%
561
16%
1683
8%
561
52%
561
22%
1089
June1st to 15thNight
57%
540
14%
1620
10%
540
61%
540
25%
1034
June16th to endNight
60%
540
16%
1620
10%
540
64%
540
26%
1019
July1st to 15thNight
60%
510
11%
1530
9%
510
61%
510
24%
1028
July16th to endNight
62%
564
14%
1595
12%
531
67%
531
25%
1013
August1st to 15thNight
65%
539
16%
1609
15%
536
66%
536
25%
1065
August16th to endNight
62%
573
17%
1893
18%
573
63%
573
23%
1229
September1st to 15thNight
55%
702
16%
1962
14%
702
56%
702
23%
1332
September16th to endNight
59%
717
25%
1980
20%
717
63%
717
28%
1253
October1st to 15thNight
51%
720
30%
2006
25%
720
57%
720
31%
1208
October16th to endNight
43%
768
31%
2306
23%
768
54%
768
30%
1342
November1st to 15thNight
44%
760
27%
2471
23%
760
53%
760
26%
1437
November16th to endNight
36%
780
25%
2535
17%
780
47%
780
22%
1537
December1st to 15thNight
28%
780
18%
2535
12%
780
38%
780
14%
1756
December16th to endNight
24%
832
17%
2704
9%
832
34%
832
12%
1952

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%8%36%6%35%5%5%6%33%
49272
Night
12%7%36%5%3445%6%38%
49000
TransparencyDay
46%6%10%17%14%3
48973
Night
41%6%12%19%16%3
48803
SeeingDay
19%14%17%19%17%11%
5854
Night
15%21%15%23%19%4
16091

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
17%9%48%5%35%5%3432%
1746
16th to endDay
15%8%47%5%23346%37%
1879
February1st to 15thDay
17%10%5%8%6%2443432%
1883
16th to endDay
17%9%38%6%23345%34%
1580
March1st to 15thDay
16%11%36%5%3445%5%32%
1896
16th to endDay
15%12%46%5%24446%34%
2111
April1st to 15thDay
12%7%25%5%25%45%7%39%
2067
16th to endDay
16%7%35%6%3445%5%38%
2283
May1st to 15thDay
15%8%36%6%36%45%5%33%
2331
16th to endDay
13%7%37%7%46%6%6%7%29%
2431
June1st to 15thDay
10%6%47%6%47%7%7%9%27%
2340
16th to endDay
8%6%36%7%46%6%7%10%32%
2340
July1st to 15thDay
13%7%38%7%5%8%7%7%7%22%
2340
16th to endDay
12%7%28%9%5%8%6%7%8%22%
2465
August1st to 15thDay
9%7%38%8%5%8%6%9%10%23%
2340
16th to endDay
15%7%48%8%5%7%6%7%7%22%
2306
September1st to 15thDay
15%8%48%7%46%5%6%6%25%
1986
16th to endDay
15%6%26%6%35%45%7%36%
1980
October1st to 15thDay
12%5%25%435%44448%
1953
16th to endDay
13%6%2442322452%
1916
November1st to 15thDay
13%7%25%42344448%
1717
16th to endDay
12%9%25%42344445%
1755
December1st to 15thDay
16%10%47%5%35%5%35%32%
1755
16th to endDay
20%9%46%5%25%435%32%
1872
January1st to 15thNight
15%8%49%6%35%43435%
2522
16th to endNight
16%10%5%8%5%3443434%
2697
February1st to 15thNight
13%11%5%7%6%3443436%
2271
16th to endNight
16%11%5%9%43434433%
1893
March1st to 15thNight
15%9%47%5%33345%36%
2063
16th to endNight
13%10%46%5%245%45%36%
2112
April1st to 15thNight
12%8%35%5%33446%44%
1890
16th to endNight
12%7%35%5%23447%42%
1676
May1st to 15thNight
14%6%27%5%35%5%5%8%36%
1619
16th to endNight
8%6%35%6%35%5%6%10%38%
1682
June1st to 15thNight
7%4345%35%7%9%11%36%
1620
16th to endNight
5%425%5%46%6%7%10%40%
1620
July1st to 15thNight
8%5%35%6%36%6%9%11%32%
1620
16th to endNight
7%326%5%47%7%9%12%33%
1703
August1st to 15thNight
7%5%25%5%46%7%8%10%37%
1620
16th to endNight
10%5%25%7%36%6%7%9%33%
1893
September1st to 15thNight
11%6%36%7%345%7%7%36%
1962
16th to endNight
10%6%25%435%45%6%46%
1980
October1st to 15thNight
11%6%24313445%51%
2006
16th to endNight
11%5%345%2233452%
2306
November1st to 15thNight
11%7%24323345%48%
2471
16th to endNight
12%9%25%42343445%
2535
December1st to 15thNight
15%10%5%8%5%24445%32%
2535
16th to endNight
17%11%48%6%35%445%28%
2704

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
51%46%16%16%4
1747
16th to endDay
44%48%20%17%4
1879
February1st to 15thDay
52%47%17%17%1
1885
16th to endDay
49%38%16%17%3
1580
March1st to 15thDay
49%49%16%15%4
1896
16th to endDay
48%5%13%19%11%2
2112
April1st to 15thDay
41%5%11%20%17%2
2067
16th to endDay
44%5%9%20%16%3
2283
May1st to 15thDay
48%6%10%21%11%2
2331
16th to endDay
47%8%13%16%11%1
2435
June1st to 15thDay
45%10%16%20%6%
2340
16th to endDay
40%10%15%18%12%2
2340
July1st to 15thDay
51%10%15%13%7%1
2201
16th to endDay
49%11%14%15%7%1
2310
August1st to 15thDay
47%11%15%15%8%1
2327
16th to endDay
53%9%12%14%8%1
2306
September1st to 15thDay
52%8%9%14%12%2
1986
16th to endDay
43%5%10%17%19%2
1980
October1st to 15thDay
35%5%7%20%24%6%
1953
16th to endDay
35%35%20%25%8%
1916
November1st to 15thDay
37%45%17%27%8%
1717
16th to endDay
40%35%18%25%6%
1755
December1st to 15thDay
51%46%16%14%5%
1755
16th to endDay
53%311%14%14%2
1872
January1st to 15thNight
50%47%14%18%4
2522
16th to endNight
49%47%16%17%4
2697
February1st to 15thNight
48%39%18%17%3
2280
16th to endNight
50%48%18%15%2
1893
March1st to 15thNight
47%410%16%16%4
2063
16th to endNight
45%413%21%12%1
2112
April1st to 15thNight
36%312%24%18%3
1890
16th to endNight
37%5%13%23%17%3
1676
May1st to 15thNight
41%8%16%20%12%
1620
16th to endNight
36%9%18%22%10%2
1684
June1st to 15thNight
34%10%22%25%6%
1620
16th to endNight
31%12%19%22%11%3
1620
July1st to 15thNight
39%10%20%19%9%1
1530
16th to endNight
33%12%24%19%9%1
1595
August1st to 15thNight
36%11%17%22%10%1
1609
16th to endNight
39%8%20%19%9%1
1893
September1st to 15thNight
41%9%16%16%13%2
1962
16th to endNight
35%7%11%21%21%2
1980
October1st to 15thNight
32%5%9%21%24%5%
2006
16th to endNight
34%3422%26%8%
2306
November1st to 15thNight
35%36%19%25%9%
2471
16th to endNight
40%36%20%22%6%
2535
December1st to 15thNight
50%49%15%14%5%
2535
16th to endNight
55%48%15%13%2
2704

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
28%20%33%9%7%
135
16th to endDay
22%37%23%9%6%
144
February1st to 15thDay
33%22%37%6%
130
16th to endDay
34%16%39%9%
81
March1st to 15thDay
25%24%27%17%41
186
16th to endDay
18%25%25%19%9%1
288
April1st to 15thDay
17%21%21%22%13%4
270
16th to endDay
18%17%18%21%18%6%
270
May1st to 15thDay
19%23%23%14%11%7%
288
16th to endDay
17%16%16%25%13%11%
331
June1st to 15thDay
15%12%9%22%22%17%
315
16th to endDay
12%11%18%20%17%19%
315
July1st to 15thDay
17%9%13%18%22%19%
305
16th to endDay
12%10%6%18%23%28%
326
August1st to 15thDay
17%6%9%19%24%22%
313
16th to endDay
21%6%5%18%22%24%
332
September1st to 15thDay
15%9%6%18%33%16%
315
16th to endDay
16%6%10%23%28%13%
314
October1st to 15thDay
18%10%13%26%23%7%
315
16th to endDay
17%13%15%23%24%6%
332
November1st to 15thDay
23%7%28%31%7%1
135
16th to endDay
17%11%34%21%14%
135
December1st to 15thDay
27%20%31%16%5%
135
16th to endDay
34%16%37%9%2
144
January1st to 15thNight
21%27%23%21%5%
780
16th to endNight
17%30%23%25%3
832
February1st to 15thNight
21%27%24%23%3
760
16th to endNight
22%32%23%19%3
631
March1st to 15thNight
18%30%24%20%6%
720
16th to endNight
17%27%23%20%10%1
768
April1st to 15thNight
15%28%20%24%9%1
632
16th to endNight
15%23%16%26%15%1
540
May1st to 15thNight
13%22%20%23%17%2
540
16th to endNight
12%19%9%26%25%5%
563
June1st to 15thNight
9%17%6%24%34%8%
540
16th to endNight
8%17%6%22%35%9%
540
July1st to 15thNight
11%12%323%40%9%
510
16th to endNight
7%17%214%42%16%
564
August1st to 15thNight
10%10%323%42%9%
539
16th to endNight
13%9%419%41%11%
573
September1st to 15thNight
13%10%421%38%10%
702
16th to endNight
13%10%7%28%35%5%
717
October1st to 15thNight
15%15%13%23%26%6%
720
16th to endNight
13%17%18%25%21%3
768
November1st to 15thNight
13%21%14%25%20%4
760
16th to endNight
17%23%16%26%14%
780
December1st to 15thNight
19%26%18%25%8%1
780
16th to endNight
23%24%21%25%4
832
Page generated at 2018-02-15 10:58:38. Version ac04

Copyright 2018 A. Danko


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