Peyton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Peyton clear sky chart from 2005-11-05 to 2017-09-19.

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
53%
15916
27%
46881
18%
15873
61%
15873
41%
25726

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
51%
899
29%
2506
20%
895
59%
895
48%
1325
January16th to endNight
50%
813
34%
2541
23%
813
62%
813
46%
1264
February1st to 15thNight
43%
702
24%
2208
16%
700
54%
700
39%
1199
February16th to endNight
38%
632
33%
1894
15%
632
55%
632
43%
991
March1st to 15thNight
47%
720
28%
2141
16%
720
57%
720
44%
1134
March16th to endNight
43%
660
27%
2004
14%
660
55%
660
41%
1072
April1st to 15thNight
35%
539
23%
1798
12%
539
51%
539
36%
950
April16th to endNight
41%
540
21%
1800
17%
540
51%
540
29%
1071
May1st to 15thNight
45%
540
19%
1648
15%
540
52%
540
29%
1024
May16th to endNight
46%
562
17%
1498
10%
561
53%
561
34%
937
June1st to 15thNight
58%
540
20%
1440
13%
540
63%
540
45%
802
June16th to endNight
65%
540
23%
1440
17%
540
69%
540
44%
813
July1st to 15thNight
66%
510
17%
1360
14%
510
67%
510
33%
851
July16th to endNight
72%
564
21%
1433
19%
531
72%
531
35%
879
August1st to 15thNight
67%
539
15%
1707
16%
536
69%
536
28%
1057
August16th to endNight
72%
573
23%
1910
26%
573
74%
573
35%
1055
September1st to 15thNight
65%
540
25%
1800
25%
540
70%
540
34%
1013
September16th to endNight
68%
504
33%
1829
33%
504
74%
504
45%
833
October1st to 15thNight
49%
619
29%
1939
18%
619
58%
619
39%
1034
October16th to endNight
63%
745
35%
2153
22%
745
71%
745
54%
1064
November1st to 15thNight
59%
875
35%
2275
19%
875
66%
875
55%
1186
November16th to endNight
55%
900
36%
2349
21%
900
63%
900
54%
1243
December1st to 15thNight
46%
900
25%
2520
14%
900
55%
900
42%
1406
December16th to endNight
44%
960
28%
2688
15%
960
55%
960
40%
1523

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
5%42442446%8%52%
47945
Night
442442445%7%55%
47055
Cloud CoverDay
5%42442446%8%52%
47943
Night
442442445%7%55%
47055
TransparencyDay
27%5%12%24%21%8%
47621
Night
25%5%13%25%21%7%
46881
SeeingDay
9%8%30%27%17%6%
5840
Night
6%430%39%16%2
15920

By Month

Percentage Cloud Cover SW (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
241421345%8%61%
1432
16th to endDay
3422312247%64%
1692
February1st to 15thDay
26%35%423347%56%
1652
16th to endDay
1435%4225%47%57%
1580
March1st to 15thDay
35%234235%5%7%56%
1818
16th to endDay
5%7%1442437%8%50%
2218
April1st to 15thDay
6%5%2332435%8%52%
2150
16th to endDay
9%7%25%4245%5%7%45%
2160
May1st to 15thDay
10%7%36%5%346%5%8%38%
2298
16th to endDay
7%5%144345%7%9%44%
2616
June1st to 15thDay
6%413425%46%9%50%
2520
16th to endDay
2213325%5%8%10%53%
2520
July1st to 15thDay
6%3245%35%6%8%10%43%
2520
16th to endDay
5%3236%37%6%7%9%43%
2635
August1st to 15thDay
5%425%5%45%6%8%10%41%
2242
16th to endDay
5%315%4346%6%9%49%
2292
September1st to 15thDay
5%31442446%9%51%
2160
16th to endDay
3312323346%65%
1875
October1st to 15thDay
6%413212337%62%
1690
16th to endDay
5%213212245%67%
1708
November1st to 15thDay
2323223448%61%
1583
16th to endDay
1313212347%67%
1608
December1st to 15thDay
24235%25%447%57%
1440
16th to endDay
36%35%42335%6%55%
1536
January1st to 15thNight
1423313447%62%
2506
16th to endNight
2423423435%64%
2541
February1st to 15thNight
25%245%2445%8%54%
2198
16th to endNight
15%34423445%60%
1894
March1st to 15thNight
2424425%45%7%56%
2141
16th to endNight
45%2331445%7%56%
2004
April1st to 15thNight
5%5%2442346%6%55%
1798
16th to endNight
9%8%24324347%47%
1800
May1st to 15thNight
10%5%245%25%5%6%8%43%
1647
16th to endNight
8%5%23325%45%10%47%
1497
June1st to 15thNight
32133245%6%11%54%
1440
16th to endNight
42133245%7%9%55%
1440
July1st to 15thNight
5%4246%36%7%7%9%43%
1440
16th to endNight
5%3235%45%6%7%10%44%
1530
August1st to 15thNight
5%5%25%6%35%7%6%9%42%
1716
16th to endNight
6%3134345%7%9%49%
1910
September1st to 15thNight
7%425%4245%5%8%49%
1800
16th to endNight
3312323446%63%
1829
October1st to 15thNight
6%423324446%57%
1939
16th to endNight
4312223437%65%
2153
November1st to 15thNight
2223313347%65%
2275
16th to endNight
2313312346%65%
2349
December1st to 15thNight
1425%42345%7%56%
2520
16th to endNight
25%24434446%55%
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
241321435%7%61%
1432
16th to endDay
3413213347%64%
1692
February1st to 15thDay
26%34424347%55%
1652
16th to endDay
1425%4225%48%56%
1580
March1st to 15thDay
35%234235%5%7%55%
1818
16th to endDay
5%6%2442437%7%50%
2216
April1st to 15thDay
6%5%2442435%8%52%
2150
16th to endDay
9%8%25%43446%7%44%
2160
May1st to 15thDay
10%7%36%5%345%6%8%38%
2298
16th to endDay
7%5%245%35%5%7%9%44%
2616
June1st to 15thDay
5%413425%5%6%9%50%
2520
16th to endDay
2213425%5%8%10%53%
2520
July1st to 15thDay
6%3245%35%6%8%10%43%
2520
16th to endDay
5%3246%36%7%8%10%42%
2635
August1st to 15thDay
5%325%5%35%6%7%10%41%
2242
16th to endDay
5%3244346%5%9%49%
2292
September1st to 15thDay
5%31442447%9%52%
2160
16th to endDay
321242335%6%64%
1875
October1st to 15thDay
6%313212347%62%
1690
16th to endDay
5%213312245%67%
1708
November1st to 15thDay
232322445%7%61%
1583
16th to endDay
1313212347%67%
1608
December1st to 15thDay
24245%2445%7%56%
1440
16th to endDay
36%35%42445%6%54%
1536
January1st to 15thNight
1423313447%62%
2506
16th to endNight
2423423435%64%
2541
February1st to 15thNight
26%245%2345%8%54%
2198
16th to endNight
15%34424445%60%
1894
March1st to 15thNight
242442445%7%56%
2141
16th to endNight
442431445%7%57%
2004
April1st to 15thNight
5%5%2433345%7%54%
1798
16th to endNight
9%8%2433335%7%47%
1800
May1st to 15thNight
10%5%25%5%245%7%8%43%
1647
16th to endNight
8%5%24325%46%10%47%
1497
June1st to 15thNight
32133345%6%11%54%
1440
16th to endNight
32133146%7%9%55%
1440
July1st to 15thNight
5%4246%36%6%8%8%43%
1440
16th to endNight
6%3245%45%5%8%11%43%
1530
August1st to 15thNight
45%26%5%45%7%6%9%42%
1716
16th to endNight
6%3144345%7%9%49%
1910
September1st to 15thNight
6%425%4345%6%8%48%
1800
16th to endNight
3312323447%63%
1829
October1st to 15thNight
6%423414446%57%
1939
16th to endNight
4312213437%65%
2153
November1st to 15thNight
2213313347%64%
2275
16th to endNight
2323323246%65%
2349
December1st to 15thNight
1425%42335%8%56%
2520
16th to endNight
25%24435%446%55%
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
20%312%30%27%5%
1433
16th to endDay
21%310%30%24%9%
1692
February1st to 15thDay
27%412%33%15%5%
1653
16th to endDay
26%39%27%25%7%
1580
March1st to 15thDay
25%5%11%25%24%8%
1818
16th to endDay
30%5%13%24%20%6%
2218
April1st to 15thDay
28%6%12%24%20%7%
2150
16th to endDay
36%5%12%23%16%5%
2160
May1st to 15thDay
40%7%13%20%16%2
2298
16th to endDay
32%9%15%22%13%6%
2620
June1st to 15thDay
26%6%15%21%19%10%
2520
16th to endDay
20%7%12%22%25%12%
2520
July1st to 15thDay
31%8%13%20%15%10%
2371
16th to endDay
30%9%15%23%16%4
2469
August1st to 15thDay
32%8%16%19%14%8%
2227
16th to endDay
28%6%12%23%23%5%
2292
September1st to 15thDay
25%6%13%20%21%11%
2160
16th to endDay
18%49%23%35%9%
1875
October1st to 15thDay
23%411%21%31%7%
1690
16th to endDay
19%28%27%31%11%
1708
November1st to 15thDay
20%310%23%26%14%
1583
16th to endDay
17%28%26%32%13%
1608
December1st to 15thDay
26%413%28%21%4
1440
16th to endDay
29%414%26%17%7%
1536
January1st to 15thNight
21%5%12%29%25%6%
2506
16th to endNight
21%410%29%24%9%
2541
February1st to 15thNight
27%5%13%31%17%4
2208
16th to endNight
23%49%30%22%9%
1894
March1st to 15thNight
25%311%26%27%6%
2141
16th to endNight
24%5%15%23%26%5%
2004
April1st to 15thNight
27%5%13%26%19%7%
1798
16th to endNight
34%6%13%25%15%5%
1800
May1st to 15thNight
35%7%15%22%14%3
1648
16th to endNight
31%9%18%21%11%7%
1498
June1st to 15thNight
22%7%20%22%13%12%
1440
16th to endNight
22%8%12%23%21%11%
1440
July1st to 15thNight
33%8%17%21%12%7%
1360
16th to endNight
29%9%16%24%16%2
1433
August1st to 15thNight
33%10%16%21%12%6%
1707
16th to endNight
27%7%13%27%17%4
1910
September1st to 15thNight
30%6%12%22%18%8%
1800
16th to endNight
19%411%26%29%8%
1829
October1st to 15thNight
26%5%12%19%27%8%
1939
16th to endNight
19%310%27%28%11%
2153
November1st to 15thNight
17%410%25%26%15%
2275
16th to endNight
20%28%26%30%11%
2349
December1st to 15thNight
25%5%14%28%20%5%
2520
16th to endNight
27%415%25%21%4
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%5%25%27%20%4
90
16th to endDay
7%11%22%39%16%2
96
February1st to 15thDay
8%8%50%26%5%
90
16th to endDay
8%53%23%13%1
81
March1st to 15thDay
313%36%30%14%
108
16th to endDay
12%19%46%14%5%1
288
April1st to 15thDay
11%18%42%17%7%3
269
16th to endDay
22%22%32%18%2
270
May1st to 15thDay
12%13%32%25%12%3
432
16th to endDay
15%9%28%24%15%5%
517
June1st to 15thDay
7%8%27%30%18%7%
495
16th to endDay
45%26%31%23%8%
495
July1st to 15thDay
9%219%31%26%11%
475
16th to endDay
8%216%29%30%12%
494
August1st to 15thDay
11%226%33%19%6%
315
16th to endDay
6%226%39%18%6%
332
September1st to 15thDay
8%336%26%16%8%
315
16th to endDay
45%30%23%26%10%
126
October1st to 15thDay
5%5%26%28%20%13%
90
16th to endDay
6%5%34%28%16%9%
96
November1st to 15thDay
36%24%27%31%6%
90
16th to endDay
6%10%45%28%6%2
90
December1st to 15thDay
410%54%23%7%
90
16th to endDay
7%6%34%38%13%
96
January1st to 15thNight
35%34%39%13%4
900
16th to endNight
3338%40%11%2
813
February1st to 15thNight
45%42%39%7%
704
16th to endNight
48%43%34%7%
632
March1st to 15thNight
45%39%37%11%1
720
16th to endNight
7%6%39%35%10%
660
April1st to 15thNight
10%7%43%29%8%
539
16th to endNight
16%9%29%33%9%1
540
May1st to 15thNight
11%7%30%36%13%
540
16th to endNight
10%432%35%14%2
563
June1st to 15thNight
4328%44%17%1
540
16th to endNight
3221%47%22%1
540
July1st to 15thNight
7%114%41%31%4
510
16th to endNight
7%8%39%40%3
564
August1st to 15thNight
8%112%43%30%3
539
16th to endNight
8%110%43%31%4
573
September1st to 15thNight
9%116%41%25%5%
540
16th to endNight
4319%43%25%4
504
October1st to 15thNight
8%5%32%31%17%4
619
16th to endNight
5%423%39%20%6%
745
November1st to 15thNight
3429%42%18%2
875
16th to endNight
45%32%39%14%3
900
December1st to 15thNight
35%38%40%10%1
900
16th to endNight
5%6%37%38%9%1
960
Page generated at 2017-09-20 02:49:56. Version ac04

Copyright 2017 A. Danko


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