Young Road Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Young Road Observatory clear sky chart from 2005-11-06 to 2024-02-10.

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
47%
24134
23%
79442
15%
24024
55%
24024
25%
48661

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 10thNight
23%
756
25%
3985
9%
737
40%
737
13%
2238
January11th to 20thNight
28%
759
29%
3922
12%
740
45%
740
15%
2076
January21st to endNight
24%
832
18%
4440
11%
814
44%
814
13%
2711
February1st to 10thNight
33%
759
26%
2286
12%
759
46%
759
25%
1418
February11th to 20thNight
24%
703
23%
2098
8%
699
39%
699
22%
1351
February21st to endNight
26%
592
23%
1776
10%
592
39%
592
22%
1146
March1st to 10thNight
32%
720
27%
2035
13%
720
44%
720
28%
1270
March11th to 20thNight
31%
720
22%
1980
9%
720
43%
720
27%
1272
March21st to endNight
34%
792
24%
2178
10%
792
44%
792
27%
1379
April1st to 10thNight
37%
720
26%
1980
13%
720
47%
720
31%
1197
April11th to 20thNight
41%
620
27%
1825
15%
620
53%
620
34%
1042
April21st to endNight
48%
540
31%
1620
18%
540
59%
540
35%
923
May1st to 10thNight
50%
540
23%
1620
12%
540
58%
540
34%
932
May11th to 20thNight
52%
531
16%
1592
11%
531
55%
531
26%
1021
May21st to endNight
64%
582
20%
1744
16%
582
66%
582
28%
1118
June1st to 10thNight
60%
540
16%
1620
13%
540
62%
540
27%
1052
June11th to 20thNight
67%
540
17%
1620
13%
540
69%
540
33%
982
June21st to endNight
69%
540
14%
1620
11%
540
70%
540
29%
1039
July1st to 10thNight
68%
525
11%
1575
10%
525
69%
525
23%
1090
July11th to 20thNight
72%
522
12%
1566
9%
522
73%
522
26%
1051
July21st to endNight
72%
591
15%
1672
13%
558
74%
558
28%
1093
August1st to 10thNight
69%
537
12%
1600
12%
534
69%
534
23%
1101
August11th to 20thNight
66%
534
19%
1615
18%
534
66%
534
24%
1090
August21st to endNight
62%
638
14%
2024
14%
638
62%
638
19%
1402
September1st to 10thNight
67%
720
19%
1980
16%
720
68%
720
29%
1289
September11th to 20thNight
58%
720
20%
1980
17%
720
61%
720
27%
1325
September21st to endNight
59%
720
26%
1980
20%
720
65%
720
33%
1242
October1st to 10thNight
57%
720
27%
1980
21%
720
63%
720
36%
1200
October11th to 20thNight
52%
720
31%
2146
24%
720
62%
720
35%
1233
October21st to endNight
51%
792
33%
2376
25%
792
63%
792
35%
1325
November1st to 10thNight
51%
740
30%
2282
24%
740
61%
740
35%
1272
November11th to 20thNight
40%
760
28%
2470
19%
760
54%
760
30%
1387
November21st to endNight
43%
760
27%
2470
18%
760
55%
760
27%
1442
December1st to 10thNight
36%
760
26%
2470
14%
760
51%
760
20%
1561
December11th to 20thNight
35%
759
28%
2902
16%
758
48%
758
22%
1650
December21st to endNight
30%
830
15%
4413
12%
817
42%
817
11%
2741

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
13%5%25%5%35%5%6%8%43%
78652
Night
13%6%25%5%345%5%7%45%
80324
TransparencyDay
38%7%11%20%19%6%
78375
Night
37%7%10%19%20%7%
80120
SeeingDay
16%9%23%24%19%8%
14015
Night
16%9%22%30%20%3
24152

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 10thDay
17%7%26%435%45%8%41%
2836
11th to 20thDay
13%5%24423346%54%
2840
21st to endDay
24%7%25%32323444%
3124
February1st to 10thDay
16%5%36%5%3446%7%42%
1875
11th to 20thDay
20%6%24434446%45%
1748
21st to endDay
20%7%25%5%33446%41%
1480
March1st to 10thDay
14%5%24433445%52%
1923
11th to 20thDay
18%5%25%5%245%47%43%
1980
21st to endDay
15%6%25%5%35%5%5%7%42%
2178
April1st to 10thDay
11%5%34435%5%5%7%48%
1980
11th to 20thDay
11%6%25%5%345%46%48%
2096
21st to endDay
9%325%5%35%45%8%52%
2340
May1st to 10thDay
9%425%4345%5%9%50%
2340
11th to 20thDay
11%427%7%45%5%6%9%40%
2301
21st to endDay
10%5%35%6%35%6%7%9%42%
2531
June1st to 10thDay
9%5%26%7%47%6%8%11%35%
2340
11th to 20thDay
6%3246%5%6%7%8%11%42%
2340
21st to endDay
45%25%7%5%6%8%8%11%38%
2340
July1st to 10thDay
8%6%37%6%5%7%8%9%9%32%
2340
11th to 20thDay
9%5%36%7%46%7%9%13%32%
2340
21st to endDay
7%436%8%48%7%9%12%32%
2547
August1st to 10thDay
8%6%27%7%5%8%7%9%12%28%
2327
11th to 20thDay
11%6%26%7%46%7%8%10%32%
2282
21st to endDay
13%6%48%7%5%6%6%6%9%31%
2312
September1st to 10thDay
9%5%36%6%45%7%7%8%40%
1980
11th to 20thDay
14%6%25%6%35%5%5%7%42%
1980
21st to endDay
16%5%25%4345%46%46%
1980
October1st to 10thDay
14%5%24333346%53%
1980
11th to 20thDay
12%423324446%56%
1811
21st to endDay
11%423443345%56%
1980
November1st to 10thDay
12%5%24433345%55%
1794
11th to 20thDay
14%423423446%54%
1710
21st to endDay
13%5%34435%5%46%49%
1710
December1st to 10thDay
18%8%25%5%35%446%39%
1710
11th to 20thDay
17%6%345%23345%48%
2153
21st to endDay
22%6%25%32345%6%40%
3124
January1st to 10thNight
18%6%25%434446%45%
4109
11th to 20thNight
12%6%245%345%6%7%46%
4120
21st to endNight
21%9%35%42333443%
4532
February1st to 10thNight
16%5%345%3445%6%46%
2286
11th to 20thNight
18%7%25%423446%44%
2098
21st to endNight
18%5%35%433446%44%
1776
March1st to 10thNight
13%6%35%435%45%6%49%
2035
11th to 20thNight
15%6%2433446%8%45%
1980
21st to endNight
12%5%35%435%5%5%7%46%
2178
April1st to 10thNight
11%42443345%8%51%
1980
11th to 20thNight
11%5%35%423348%53%
1825
21st to endNight
9%42443445%8%54%
1620
May1st to 10thNight
8%5%245%445%5%9%51%
1620
11th to 20thNight
10%6%26%6%36%6%7%9%40%
1592
21st to endNight
9%6%25%6%36%7%7%8%41%
1744
June1st to 10thNight
8%5%35%5%46%7%8%13%36%
1620
11th to 20thNight
5%425%6%35%6%8%11%44%
1620
21st to endNight
7%425%6%37%7%9%11%38%
1620
July1st to 10thNight
9%5%37%5%47%8%9%11%33%
1620
11th to 20thNight
7%427%6%38%7%10%14%32%
1620
21st to endNight
5%5%35%5%46%9%11%12%35%
1771
August1st to 10thNight
7%6%27%7%5%7%8%10%12%30%
1611
11th to 20thNight
12%5%246%45%6%9%13%34%
1615
21st to endNight
12%7%36%7%5%6%6%6%9%32%
2024
September1st to 10thNight
9%5%35%6%35%6%7%11%41%
1980
11th to 20thNight
13%6%25%6%35%5%6%7%41%
1980
21st to endNight
13%425%5%2445%7%48%
1980
October1st to 10thNight
13%42443345%6%52%
1980
11th to 20thNight
12%5%14333345%56%
2146
21st to endNight
11%424324445%57%
2376
November1st to 10thNight
11%5%24413346%57%
2282
11th to 20thNight
13%5%24333346%53%
2470
21st to endNight
15%4145%335%5%6%48%
2470
December1st to 10thNight
15%6%25%4245%46%44%
2470
11th to 20thNight
17%5%25%423445%51%
3042
21st to endNight
19%8%35%5%3445%7%37%
4532

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 10thDay
41%5%6%19%21%8%
2837
11th to 20thDay
33%35%23%27%9%
2840
21st to endDay
46%2318%23%8%
3124
February1st to 10thDay
43%48%19%19%6%
1875
11th to 20thDay
42%46%19%22%7%
1758
21st to endDay
44%5%7%15%19%9%
1480
March1st to 10thDay
35%48%19%23%11%
1923
11th to 20thDay
42%6%10%19%16%7%
1980
21st to endDay
41%5%10%21%19%4
2178
April1st to 10thDay
35%5%9%22%22%7%
1980
11th to 20thDay
37%5%8%18%22%10%
2096
21st to endDay
30%6%9%27%24%4
2340
May1st to 10thDay
31%6%13%24%22%4
2340
11th to 20thDay
41%7%15%20%15%2
2305
21st to endDay
37%8%12%24%17%2
2531
June1st to 10thDay
39%10%17%21%11%2
2340
11th to 20thDay
32%9%19%25%13%1
2340
21st to endDay
35%11%17%20%12%4
2340
July1st to 10thDay
41%13%16%18%9%2
2275
11th to 20thDay
39%14%21%17%6%4
2271
21st to endDay
37%12%22%20%8%1
2405
August1st to 10thDay
43%12%17%20%6%1
2314
11th to 20thDay
43%11%18%16%10%2
2282
21st to endDay
48%10%14%17%9%2
2312
September1st to 10thDay
39%8%14%18%17%4
1980
11th to 20thDay
41%7%10%18%22%2
1980
21st to endDay
39%49%21%19%7%
1980
October1st to 10thDay
33%48%22%26%7%
1980
11th to 20thDay
30%47%25%26%8%
1811
21st to endDay
31%35%19%30%12%
1980
November1st to 10thDay
33%47%16%28%12%
1794
11th to 20thDay
32%47%21%25%11%
1710
21st to endDay
36%5%8%20%25%7%
1710
December1st to 10thDay
46%5%8%18%16%7%
1710
11th to 20thDay
40%35%18%23%10%
2150
21st to endDay
44%5%7%19%22%4
3124
January1st to 10thNight
40%45%16%26%8%
4109
11th to 20thNight
36%5%6%21%23%9%
4120
21st to endNight
46%4313%26%8%
4532
February1st to 10thNight
39%49%19%21%8%
2286
11th to 20thNight
42%45%19%22%8%
2099
21st to endNight
41%5%7%16%20%10%
1776
March1st to 10thNight
37%48%15%23%13%
2035
11th to 20thNight
37%6%11%16%21%8%
1980
21st to endNight
37%6%9%21%21%6%
2178
April1st to 10thNight
32%6%10%20%23%9%
1980
11th to 20thNight
32%37%23%24%11%
1825
21st to endNight
30%6%10%25%22%7%
1620
May1st to 10thNight
30%7%13%24%21%6%
1620
11th to 20thNight
38%9%16%19%17%2
1593
21st to endNight
37%8%12%24%16%3
1745
June1st to 10thNight
36%11%19%20%13%1
1620
11th to 20thNight
31%9%19%26%12%3
1620
21st to endNight
34%12%20%19%12%4
1620
July1st to 10thNight
38%15%20%15%9%3
1575
11th to 20thNight
35%14%24%18%7%2
1566
21st to endNight
33%14%25%20%6%1
1672
August1st to 10thNight
40%12%20%22%5%
1600
11th to 20thNight
37%14%18%18%11%1
1615
21st to endNight
45%11%16%17%9%2
2024
September1st to 10thNight
35%11%15%17%18%4
1980
11th to 20thNight
40%8%12%16%19%4
1980
21st to endNight
36%6%11%18%22%7%
1980
October1st to 10thNight
32%6%9%18%27%7%
1980
11th to 20thNight
33%48%21%25%10%
2146
21st to endNight
30%45%18%30%14%
2376
November1st to 10thNight
31%47%19%27%13%
2282
11th to 20thNight
33%46%18%25%14%
2470
21st to endNight
35%5%7%18%26%8%
2470
December1st to 10thNight
41%6%8%20%19%7%
2470
11th to 20thNight
37%37%16%28%9%
3044
21st to endNight
47%5%6%20%19%3
4532

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 10thDay
25%19%38%15%3
270
11th to 20thDay
26%16%34%17%6%
270
21st to endDay
25%24%38%9%4
297
February1st to 10thDay
22%19%38%17%3
267
11th to 20thDay
36%16%35%12%
240
21st to endDay
29%19%41%10%2
198
March1st to 10thDay
19%15%34%25%7%
363
11th to 20thDay
23%15%36%18%6%1
420
21st to endDay
21%17%32%21%8%
462
April1st to 10thDay
21%15%28%24%11%1
420
11th to 20thDay
14%15%32%23%14%2
412
21st to endDay
13%11%31%24%18%4
420
May1st to 10thDay
12%13%33%23%14%5%
423
11th to 20thDay
14%422%30%20%9%
447
21st to endDay
14%5%16%27%26%12%
485
June1st to 10thDay
12%416%29%29%10%
450
11th to 20thDay
6%5%17%26%25%21%
450
21st to endDay
6%420%31%24%15%
450
July1st to 10thDay
8%211%26%31%23%
445
11th to 20thDay
9%28%25%37%19%
444
21st to endDay
6%19%29%34%20%
488
August1st to 10thDay
14%314%24%26%19%
446
11th to 20thDay
12%37%25%35%18%
439
21st to endDay
12%412%23%32%16%
495
September1st to 10thDay
10%312%26%35%13%
450
11th to 20thDay
16%312%24%35%10%
450
21st to endDay
17%417%27%27%10%
450
October1st to 10thDay
18%324%30%16%10%
450
11th to 20thDay
13%9%24%24%23%6%
450
21st to endDay
16%10%25%27%18%4
495
November1st to 10thDay
18%9%25%29%16%3
392
11th to 20thDay
16%16%38%24%41
270
21st to endDay
12%15%36%24%12%2
270
December1st to 10thDay
29%19%30%19%41
270
11th to 20thDay
27%13%34%19%5%1
270
21st to endDay
32%18%26%16%5%3
297
January1st to 10thNight
22%19%31%23%5%
760
11th to 20thNight
22%17%29%23%9%
760
21st to endNight
22%17%32%25%3
836
February1st to 10thNight
20%13%31%31%5%
759
11th to 20thNight
23%16%33%26%3
703
21st to endNight
22%15%33%27%3
592
March1st to 10thNight
16%16%33%30%5%
720
11th to 20thNight
18%14%32%26%10%1
720
21st to endNight
17%14%30%30%9%
792
April1st to 10thNight
16%13%31%28%12%
720
11th to 20thNight
15%12%28%29%16%1
620
21st to endNight
12%7%28%32%19%1
540
May1st to 10thNight
10%8%26%35%19%1
540
11th to 20thNight
11%5%21%34%26%3
531
21st to endNight
12%212%34%34%6%
584
June1st to 10thNight
11%315%35%31%5%
540
11th to 20thNight
7%215%30%35%11%
540
21st to endNight
8%212%36%33%8%
540
July1st to 10thNight
10%18%28%40%13%
525
11th to 20thNight
9%15%29%44%12%
522
21st to endNight
6%29%31%44%8%
591
August1st to 10thNight
10%28%29%42%9%
537
11th to 20thNight
13%36%31%41%7%
534
21st to endNight
13%47%29%37%10%
638
September1st to 10thNight
11%29%30%40%8%
720
11th to 20thNight
16%412%26%37%5%
720
21st to endNight
15%314%30%34%3
720
October1st to 10thNight
14%318%32%26%6%
720
11th to 20thNight
15%6%23%30%23%3
720
21st to endNight
13%10%21%30%24%2
792
November1st to 10thNight
14%8%21%34%21%2
740
11th to 20thNight
16%10%28%31%13%1
760
21st to endNight
17%10%26%31%14%2
760
December1st to 10thNight
19%16%24%32%9%1
760
11th to 20thNight
20%12%28%28%11%1
760
21st to endNight
29%13%24%28%6%
836
Page generated at 2024-02-07 06:11:57. Version ac07

Copyright 2024 Attilla Danko


Young Road Observatory Clear Sky Chart |Charts Home