Fanthorp Inn State Historic Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fanthorp Inn State Historic Site 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
50%
15443
25%
46964
17%
15394
57%
15394
32%
27703

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
33%
900
24%
2327
10%
895
42%
895
27%
1551
January16th to endNight
30%
960
28%
2496
10%
960
41%
960
30%
1609
February1st to 15thNight
31%
758
25%
2159
10%
752
41%
752
26%
1360
February16th to endNight
22%
555
26%
1817
9%
555
37%
555
25%
1099
March1st to 15thNight
28%
540
25%
1980
13%
540
42%
540
22%
1206
March16th to endNight
33%
576
23%
2112
15%
576
45%
576
27%
1209
April1st to 15thNight
34%
539
22%
1962
13%
539
48%
539
26%
1124
April16th to endNight
35%
540
23%
1800
16%
540
47%
540
27%
1068
May1st to 15thNight
35%
539
20%
1649
14%
539
44%
539
29%
1005
May16th to endNight
53%
563
25%
1685
22%
561
63%
561
38%
962
June1st to 15thNight
75%
540
20%
1620
23%
540
79%
540
48%
827
June16th to endNight
77%
540
20%
1620
23%
540
79%
540
38%
934
July1st to 15thNight
79%
510
21%
1530
24%
510
81%
510
41%
842
July16th to endNight
82%
564
19%
1594
23%
531
83%
531
40%
888
August1st to 15thNight
89%
539
29%
1610
33%
536
89%
536
56%
755
August16th to endNight
77%
573
17%
1934
21%
573
78%
573
28%
1161
September1st to 15thNight
75%
540
16%
1980
19%
540
77%
540
29%
1141
September16th to endNight
72%
513
28%
1891
32%
513
73%
513
32%
1027
October1st to 15thNight
69%
586
34%
1906
29%
586
72%
586
41%
962
October16th to endNight
57%
704
35%
2112
23%
704
65%
704
45%
1096
November1st to 15thNight
50%
700
28%
2100
19%
700
56%
700
34%
1231
November16th to endNight
45%
804
31%
2244
17%
804
53%
804
35%
1344
December1st to 15thNight
36%
900
25%
2340
12%
900
43%
900
27%
1579
December16th to endNight
35%
960
21%
2496
9%
960
41%
960
26%
1723

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
11%5%25%5%35%5%5%7%42%
47904
Night
10%42432345%8%50%
47167
TransparencyDay
39%7%11%17%16%7%
47604
Night
32%6%12%20%17%9%
46972
SeeingDay
9%5%17%27%29%10%
5439
Night
12%6%25%34%18%2
15444

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
18%42443244445%
1611
16th to endDay
17%6%2432424446%
1728
February1st to 15thDay
16%7%34313435%45%
1707
16th to endDay
18%6%35%423335%44%
1655
March1st to 15thDay
21%7%25%423345%39%
1980
16th to endDay
14%6%35%424345%45%
2110
April1st to 15thDay
12%7%36%434446%41%
1986
16th to endDay
11%6%25%6%3435%7%41%
2160
May1st to 15thDay
10%6%37%6%346%6%7%35%
2298
16th to endDay
8%436%6%46%6%6%8%37%
2430
June1st to 15thDay
5%2246%46%6%7%9%43%
2340
16th to endDay
6%426%8%5%8%7%8%9%32%
2340
July1st to 15thDay
8%425%6%37%7%8%10%35%
2340
16th to endDay
5%336%7%49%8%8%12%31%
2466
August1st to 15thDay
32136%46%5%7%11%48%
2340
16th to endDay
6%426%7%47%7%7%9%35%
2261
September1st to 15thDay
8%5%26%6%46%5%6%7%40%
1980
16th to endDay
7%435%6%35%6%6%7%42%
1881
October1st to 15thDay
8%4146%34445%52%
1712
16th to endDay
10%312213335%61%
1760
November1st to 15thDay
7%6%35%5%25%35%7%47%
1758
16th to endDay
14%5%2442344450%
1713
December1st to 15thDay
18%8%35%433245%40%
1620
16th to endDay
18%8%35%6%23446%37%
1728
January1st to 15thNight
16%7%24324335%46%
2327
16th to endNight
18%424313336%48%
2496
February1st to 15thNight
13%7%25%323235%48%
2156
16th to endNight
15%5%23433445%48%
1817
March1st to 15thNight
17%6%25%322346%44%
1980
16th to endNight
10%5%34323447%49%
2112
April1st to 15thNight
8%424425%45%8%47%
1962
16th to endNight
11%6%15%324448%47%
1800
May1st to 15thNight
7%5%25%5%3446%9%44%
1649
16th to endNight
42243346%5%10%52%
1683
June1st to 15thNight
22132235%7%11%57%
1620
16th to endNight
2213425%6%7%11%50%
1620
July1st to 15thNight
332332445%12%53%
1620
16th to endNight
3112425%6%7%13%49%
1702
August1st to 15thNight
21221246%12%63%
1620
16th to endNight
5%315%436%5%7%12%44%
1934
September1st to 15thNight
6%4244345%6%10%46%
1980
16th to endNight
7%31342445%9%51%
1891
October1st to 15thNight
5%323323347%61%
1906
16th to endNight
8%31322222465%
2112
November1st to 15thNight
9%42433335%5%53%
2100
16th to endNight
12%424312435%54%
2244
December1st to 15thNight
16%7%25%42335%6%42%
2340
16th to endNight
15%8%25%423435%43%
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
41%47%13%22%10%
1612
16th to endDay
41%26%14%21%13%
1728
February1st to 15thDay
40%5%5%16%19%12%
1708
16th to endDay
44%36%15%18%11%
1655
March1st to 15thDay
47%5%6%12%20%7%
1980
16th to endDay
41%5%8%16%22%5%
2112
April1st to 15thDay
43%5%7%17%16%10%
1986
16th to endDay
40%6%10%16%17%7%
2160
May1st to 15thDay
45%7%11%14%13%7%
2298
16th to endDay
40%9%12%19%14%2
2434
June1st to 15thDay
34%9%15%22%15%2
2340
16th to endDay
44%10%14%19%10%1
2340
July1st to 15thDay
39%10%18%21%9%
2201
16th to endDay
38%14%18%20%7%
2311
August1st to 15thDay
27%10%18%29%12%
2326
16th to endDay
41%11%18%19%6%1
2261
September1st to 15thDay
39%10%13%19%12%4
1980
16th to endDay
37%9%11%17%16%8%
1881
October1st to 15thDay
33%5%9%17%17%16%
1712
16th to endDay
26%35%14%31%18%
1760
November1st to 15thDay
35%6%10%18%19%9%
1758
16th to endDay
36%47%11%23%16%
1713
December1st to 15thDay
47%47%16%16%7%
1620
16th to endDay
48%48%15%15%8%
1728
January1st to 15thNight
41%35%14%20%13%
2327
16th to endNight
38%45%14%22%14%
2496
February1st to 15thNight
39%35%13%21%15%
2166
16th to endNight
38%5%7%16%17%15%
1817
March1st to 15thNight
41%47%15%19%11%
1980
16th to endNight
35%5%11%17%20%9%
2112
April1st to 15thNight
34%6%10%18%17%12%
1962
16th to endNight
35%6%11%19%16%10%
1800
May1st to 15thNight
36%6%13%19%16%8%
1650
16th to endNight
26%8%16%28%17%3
1685
June1st to 15thNight
18%7%19%29%23%2
1620
16th to endNight
25%10%19%29%13%1
1620
July1st to 15thNight
23%9%23%33%10%
1530
16th to endNight
21%11%29%29%7%
1594
August1st to 15thNight
13%6%25%40%13%
1610
16th to endNight
29%12%24%24%6%1
1934
September1st to 15thNight
31%9%21%20%11%5%
1980
16th to endNight
28%8%13%20%18%9%
1891
October1st to 15thNight
23%5%11%24%18%16%
1906
16th to endNight
24%35%16%29%21%
2112
November1st to 15thNight
32%5%10%21%20%9%
2100
16th to endNight
32%47%13%22%18%
2244
December1st to 15thNight
42%5%9%17%17%8%
2340
16th to endNight
44%5%6%14%17%10%
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
22%10%35%24%6%1
90
16th to endDay
17%17%43%12%7%1
96
February1st to 15thDay
8%23%36%24%6%
90
16th to endDay
14%24%30%25%3
81
March1st to 15thDay
22%23%34%12%7%
90
16th to endDay
9%12%35%27%15%
96
April1st to 15thDay
10%16%36%21%13%1
105
16th to endDay
17%9%31%25%14%1
270
May1st to 15thDay
13%10%37%28%8%1
435
16th to endDay
9%6%29%33%18%3
517
June1st to 15thDay
5%113%36%35%7%
495
16th to endDay
8%110%33%33%13%
495
July1st to 15thDay
6%7%31%38%15%
475
16th to endDay
3226%45%20%
515
August1st to 15thDay
6%221%52%16%
493
16th to endDay
12%6%14%44%21%
301
September1st to 15thDay
36%18%47%23%
135
16th to endDay
4225%33%34%
108
October1st to 15thDay
16%45%40%6%
90
16th to endDay
18%316%17%35%8%
96
November1st to 15thDay
15%6%24%33%18%1
90
16th to endDay
20%10%28%27%6%6%
90
December1st to 15thDay
28%420%30%7%8%
90
16th to endDay
21%22%32%19%3
96
January1st to 15thNight
20%12%29%29%8%
900
16th to endNight
20%12%33%27%6%
960
February1st to 15thNight
16%13%34%29%5%
758
16th to endNight
19%12%42%23%2
555
March1st to 15thNight
19%10%38%25%5%
540
16th to endNight
12%8%42%28%7%
576
April1st to 15thNight
9%11%41%32%4
539
16th to endNight
15%7%39%27%10%
540
May1st to 15thNight
9%9%41%31%7%
540
16th to endNight
5%232%38%19%1
563
June1st to 15thNight
315%51%26%2
540
16th to endNight
211%51%29%4
540
July1st to 15thNight
47%49%33%5%
510
16th to endNight
2448%39%5%
564
August1st to 15thNight
3247%42%3
539
16th to endNight
6%6%35%44%5%
573
September1st to 15thNight
7%16%33%44%6%
540
16th to endNight
11%8%31%40%7%
513
October1st to 15thNight
6%315%40%29%4
586
16th to endNight
9%325%33%24%2
704
November1st to 15thNight
11%5%30%32%19%1
700
16th to endNight
15%8%28%30%16%
804
December1st to 15thNight
20%9%29%29%10%
900
16th to endNight
21%10%30%28%8%
960
Page generated at 2017-09-23 05:43:38. Version ac04

Copyright 2017 A. Danko


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