North Sterling State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the North Sterling State Park clear sky chart from 2005-11-06 to 2024-01-12.

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%
24630
25%
74406
16%
24579
58%
24579
36%
42291

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
47%
950
29%
2647
17%
946
56%
946
42%
1458
January11th to 20thNight
44%
908
29%
2541
17%
908
55%
908
38%
1447
January21st to endNight
35%
914
27%
2696
13%
914
49%
914
35%
1555
February1st to 10thNight
35%
720
21%
2279
11%
720
47%
720
29%
1388
February11th to 20thNight
39%
701
23%
2098
13%
700
48%
700
33%
1226
February21st to endNight
37%
592
29%
1776
13%
592
51%
592
35%
1022
March1st to 10thNight
44%
720
26%
2160
15%
720
53%
720
36%
1221
March11th to 20thNight
44%
702
25%
2114
16%
702
52%
702
35%
1220
March21st to endNight
38%
594
20%
1980
12%
594
47%
594
26%
1183
April1st to 10thNight
37%
540
20%
1800
12%
540
50%
540
25%
1079
April11th to 20thNight
38%
533
20%
1777
13%
533
49%
533
26%
1058
April21st to endNight
40%
540
20%
1735
16%
540
48%
540
25%
1084
May1st to 10thNight
45%
540
18%
1620
15%
540
50%
540
27%
1039
May11th to 20thNight
48%
531
15%
1510
12%
531
50%
531
27%
990
May21st to endNight
45%
582
14%
1552
8%
582
49%
582
27%
1054
June1st to 10thNight
61%
540
16%
1440
8%
540
64%
540
39%
865
June11th to 20thNight
54%
540
19%
1440
12%
540
58%
540
40%
849
June21st to endNight
61%
540
21%
1440
14%
540
64%
540
39%
854
July1st to 10thNight
65%
525
17%
1400
11%
525
67%
525
38%
856
July11th to 20thNight
73%
522
26%
1392
20%
522
75%
522
44%
776
July21st to endNight
71%
591
24%
1488
19%
558
71%
558
41%
863
August1st to 10thNight
66%
537
17%
1531
16%
534
67%
534
32%
967
August11th to 20thNight
70%
534
25%
1778
27%
534
74%
534
39%
924
August21st to endNight
70%
594
28%
1980
32%
594
74%
594
44%
971
September1st to 10thNight
66%
540
29%
1800
30%
540
72%
540
40%
931
September11th to 20thNight
63%
540
32%
1894
32%
540
70%
540
43%
903
September21st to endNight
61%
540
33%
1980
31%
540
70%
540
43%
918
October1st to 10thNight
54%
583
31%
2023
25%
583
61%
583
33%
1067
October11th to 20thNight
52%
720
33%
2160
19%
720
61%
720
46%
1089
October21st to endNight
51%
958
30%
2542
15%
958
58%
958
43%
1438
November1st to 10thNight
55%
925
31%
2405
16%
925
61%
925
49%
1307
November11th to 20thNight
48%
950
33%
2470
16%
950
56%
950
43%
1419
November21st to endNight
49%
950
30%
2489
14%
950
59%
950
43%
1460
December1st to 10thNight
42%
950
25%
2660
12%
950
52%
950
39%
1529
December11th to 20thNight
44%
948
30%
3078
16%
948
54%
948
35%
1641
December21st to endNight
41%
1036
18%
4731
13%
1026
51%
1026
22%
2640

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
6%5%2443445%8%55%
74816
Night
7%6%2443445%7%53%
74924
TransparencyDay
27%5%12%27%21%7%
74520
Night
30%5%12%27%20%6%
74742
SeeingDay
10%5%23%32%23%7%
14537
Night
9%5%28%43%13%1
24646

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 10thDay
36%24423447%60%
1518
11th to 20thDay
5%7%3444347%7%53%
1448
21st to endDay
46%36%4345%5%8%53%
1676
February1st to 10thDay
38%47%5%35%35%8%48%
1679
11th to 20thDay
47%35%5%35%5%6%7%49%
1749
21st to endDay
5%7%35%5%34447%52%
1480
March1st to 10thDay
5%6%25%43445%7%54%
1800
11th to 20thDay
8%5%244345%47%54%
1843
21st to endDay
8%6%36%5%345%5%9%45%
2376
April1st to 10thDay
9%7%24425%45%6%51%
2160
11th to 20thDay
13%7%25%43446%7%45%
2131
21st to endDay
10%6%35%4345%6%8%46%
2223
May1st to 10thDay
12%5%35%426%5%6%7%45%
2340
11th to 20thDay
13%6%25%43346%9%45%
2382
21st to endDay
10%424435%5%7%9%47%
2724
June1st to 10thDay
6%213325%5%7%9%56%
2520
11th to 20thDay
6%313425%46%9%57%
2520
21st to endDay
33143245%7%8%60%
2520
July1st to 10thDay
6%324335%5%6%10%54%
2520
11th to 20thDay
32133345%6%9%61%
2520
21st to endDay
4314435%6%8%10%52%
2742
August1st to 10thDay
5%2244345%7%10%53%
2396
11th to 20thDay
431342446%8%61%
2123
21st to endDay
5%312333448%63%
2376
September1st to 10thDay
7%313423446%62%
2160
11th to 20thDay
7%21332345%6%63%
2066
21st to endDay
8%413312346%66%
1980
October1st to 10thDay
11%5%22323445%59%
1935
11th to 20thDay
7%414323345%65%
1800
21st to endDay
8%424423346%61%
1796
November1st to 10thDay
35%1432345%8%63%
1673
11th to 20thDay
4423334447%62%
1710
21st to endDay
46%34323446%61%
1690
December1st to 10thDay
47%37%42336%7%54%
1520
11th to 20thDay
46%25%425%45%8%54%
1926
21st to endDay
6%10%35%43445%7%48%
2794
January1st to 10thNight
46%35%42335%8%58%
2647
11th to 20thNight
46%344245%5%7%56%
2541
21st to endNight
47%36%6%24447%52%
2696
February1st to 10thNight
5%8%46%6%35%5%5%6%48%
2279
11th to 20thNight
47%36%6%35%46%8%50%
2098
21st to endNight
38%37%43345%6%54%
1776
March1st to 10thNight
6%7%35%42445%7%54%
2160
11th to 20thNight
8%7%24425%45%6%52%
2114
21st to endNight
8%9%36%43446%7%45%
1980
April1st to 10thNight
9%7%36%5%245%46%48%
1800
11th to 20thNight
13%7%35%43445%6%48%
1777
21st to endNight
15%7%26%434448%44%
1735
May1st to 10thNight
13%5%245%35%6%6%10%40%
1620
11th to 20thNight
15%7%244245%5%7%45%
1509
21st to endNight
12%5%25%6%45%6%7%9%40%
1552
June1st to 10thNight
6%314436%6%6%11%49%
1440
11th to 20thNight
8%3133245%6%9%54%
1440
21st to endNight
5%325%5%35%6%7%10%49%
1440
July1st to 10thNight
7%4245%36%5%7%10%47%
1440
11th to 20thNight
4213435%6%6%12%55%
1440
21st to endNight
5%325%5%35%47%11%50%
1576
August1st to 10thNight
5%5%25%6%46%7%7%10%43%
1539
11th to 20thNight
5%324435%5%6%10%55%
1778
21st to endNight
431343446%9%57%
1980
September1st to 10thNight
5%414425%46%7%57%
1800
11th to 20thNight
6%42342345%6%62%
1894
21st to endNight
7%31332345%6%63%
1980
October1st to 10thNight
12%414323346%57%
2023
11th to 20thNight
7%5%13323336%64%
2160
21st to endNight
7%6%24423346%60%
2542
November1st to 10thNight
5%32442446%7%61%
2405
11th to 20thNight
5%425%434446%59%
2470
21st to endNight
5%7%24434446%59%
2489
December1st to 10thNight
46%445%345%5%6%56%
2660
11th to 20thNight
46%3442445%8%57%
3271
21st to endNight
8%10%35%4345%5%7%47%
4873

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
26%5%13%35%19%3
1519
11th to 20thDay
30%5%12%30%18%4
1448
21st to endDay
29%416%31%16%3
1676
February1st to 10thDay
36%5%13%27%15%4
1679
11th to 20thDay
33%5%10%28%19%5%
1759
21st to endDay
32%5%10%27%19%6%
1480
March1st to 10thDay
30%412%27%22%6%
1800
11th to 20thDay
29%6%13%24%23%5%
1843
21st to endDay
36%6%14%25%15%3
2376
April1st to 10thDay
32%6%12%25%17%7%
2160
11th to 20thDay
37%5%14%24%16%5%
2134
21st to endDay
34%5%12%28%19%2
2223
May1st to 10thDay
37%6%14%28%13%1
2340
11th to 20thDay
36%7%15%29%12%1
2386
21st to endDay
31%9%17%26%14%4
2724
June1st to 10thDay
23%7%19%30%16%5%
2520
11th to 20thDay
23%6%12%24%24%10%
2520
21st to endDay
19%6%11%28%27%9%
2520
July1st to 10thDay
26%6%10%24%24%9%
2451
11th to 20thDay
18%6%10%27%26%12%
2445
21st to endDay
24%7%15%28%19%7%
2590
August1st to 10thDay
24%8%16%30%14%8%
2380
11th to 20thDay
20%6%10%29%26%10%
2123
21st to endDay
21%48%25%29%13%
2376
September1st to 10thDay
22%5%8%25%25%16%
2160
11th to 20thDay
20%5%9%22%28%16%
2066
21st to endDay
21%37%24%34%10%
1980
October1st to 10thDay
28%5%9%23%27%9%
1935
11th to 20thDay
22%48%28%25%13%
1800
21st to endDay
26%410%28%23%10%
1796
November1st to 10thDay
21%414%27%25%10%
1673
11th to 20thDay
24%47%32%28%6%
1710
21st to endDay
26%311%27%26%7%
1690
December1st to 10thDay
30%5%10%30%20%4
1520
11th to 20thDay
28%5%10%30%25%2
1924
21st to endDay
36%5%12%30%15%3
2794
January1st to 10thNight
27%313%32%22%3
2647
11th to 20thNight
28%5%11%28%25%4
2541
21st to endNight
32%413%32%16%3
2696
February1st to 10thNight
37%5%13%25%16%4
2279
11th to 20thNight
32%6%13%29%16%3
2098
21st to endNight
31%5%10%27%22%6%
1776
March1st to 10thNight
30%49%26%24%6%
2160
11th to 20thNight
32%410%23%25%5%
2114
21st to endNight
37%7%15%24%15%2
1980
April1st to 10thNight
37%6%11%22%17%7%
1800
11th to 20thNight
37%6%14%24%16%4
1777
21st to endNight
40%6%9%26%18%2
1735
May1st to 10thNight
38%8%15%26%12%1
1620
11th to 20thNight
39%7%17%25%9%2
1510
21st to endNight
39%9%19%17%9%6%
1552
June1st to 10thNight
27%9%25%24%12%3
1440
11th to 20thNight
26%8%16%24%17%9%
1440
21st to endNight
27%9%13%25%22%4
1440
July1st to 10thNight
31%7%15%25%18%5%
1400
11th to 20thNight
22%8%12%27%20%11%
1392
21st to endNight
26%7%17%29%16%4
1488
August1st to 10thNight
33%10%20%20%13%4
1531
11th to 20thNight
24%7%13%27%21%8%
1778
21st to endNight
22%5%12%26%24%10%
1980
September1st to 10thNight
25%6%9%23%24%13%
1800
11th to 20thNight
22%5%10%26%25%12%
1894
21st to endNight
22%48%29%27%11%
1980
October1st to 10thNight
29%5%10%22%26%9%
2023
11th to 20thNight
22%49%28%24%13%
2160
21st to endNight
27%412%23%23%11%
2542
November1st to 10thNight
22%5%12%26%27%9%
2405
11th to 20thNight
27%410%27%24%8%
2470
21st to endNight
28%49%26%26%7%
2489
December1st to 10thNight
29%414%28%19%5%
2660
11th to 20thNight
27%49%34%24%3
3272
21st to endNight
36%5%11%30%16%2
4873

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
7%426%41%18%4
270
11th to 20thDay
13%9%29%35%14%
243
21st to endDay
10%7%44%31%7%1
264
February1st to 10thDay
8%9%41%34%8%
240
11th to 20thDay
10%10%36%33%9%2
240
21st to endDay
9%11%38%33%8%2
198
March1st to 10thDay
10%8%30%32%18%3
240
11th to 20thDay
12%8%32%29%18%2
266
21st to endDay
14%9%33%32%10%2
462
April1st to 10thDay
14%15%31%23%13%3
420
11th to 20thDay
17%12%32%25%11%2
412
21st to endDay
16%11%29%23%17%5%
483
May1st to 10thDay
16%6%26%29%18%4
603
11th to 20thDay
19%420%29%23%5%
625
21st to endDay
14%6%24%27%22%7%
679
June1st to 10thDay
8%417%33%26%13%
630
11th to 20thDay
8%423%36%22%7%
630
21st to endDay
6%221%36%29%6%
630
July1st to 10thDay
9%13%33%35%10%
621
11th to 20thDay
5%12%33%35%14%
618
21st to endDay
5%110%33%38%12%
684
August1st to 10thDay
7%111%31%41%9%
587
11th to 20thDay
4218%32%28%15%
437
21st to endDay
5%119%32%31%12%
495
September1st to 10thDay
8%316%33%27%12%
450
11th to 20thDay
5%214%28%34%17%
356
21st to endDay
11%319%27%27%13%
270
October1st to 10thDay
15%319%23%22%18%
270
11th to 20thDay
7%10%29%29%15%10%
270
21st to endDay
12%10%23%30%18%6%
297
November1st to 10thDay
6%8%29%33%19%5%
270
11th to 20thDay
7%7%28%40%15%3
270
21st to endDay
9%6%28%36%19%3
270
December1st to 10thDay
8%11%27%39%15%1
270
11th to 20thDay
12%7%30%41%10%
270
21st to endDay
12%10%30%36%11%1
297
January1st to 10thNight
7%7%31%42%12%1
950
11th to 20thNight
8%7%33%42%9%1
908
21st to endNight
8%6%41%37%7%1
914
February1st to 10thNight
9%7%41%37%7%
720
11th to 20thNight
8%6%38%40%8%
704
21st to endNight
8%6%42%40%4
592
March1st to 10thNight
9%7%33%42%9%
720
11th to 20thNight
11%5%33%40%10%1
702
21st to endNight
13%6%35%39%7%
594
April1st to 10thNight
13%9%35%37%6%
540
11th to 20thNight
16%8%32%38%6%
533
21st to endNight
17%9%28%34%11%
540
May1st to 10thNight
16%7%26%38%11%
540
11th to 20thNight
21%321%39%15%1
531
21st to endNight
15%429%35%16%
584
June1st to 10thNight
9%322%43%21%1
540
11th to 20thNight
9%5%28%48%11%
540
21st to endNight
7%121%52%18%1
540
July1st to 10thNight
8%215%50%24%1
525
11th to 20thNight
6%115%53%24%2
522
21st to endNight
6%110%50%32%1
591
August1st to 10thNight
7%113%50%27%1
537
11th to 20thNight
5%115%56%23%
534
21st to endNight
5%116%56%22%
594
September1st to 10thNight
7%319%51%20%1
540
11th to 20thNight
8%119%48%22%1
540
21st to endNight
8%322%48%19%
540
October1st to 10thNight
15%421%38%19%2
583
11th to 20thNight
11%429%40%15%1
720
21st to endNight
11%5%26%45%12%1
958
November1st to 10thNight
7%328%49%13%1
925
11th to 20thNight
8%7%31%44%9%
950
21st to endNight
9%6%30%44%12%1
950
December1st to 10thNight
7%7%38%41%8%
950
11th to 20thNight
9%6%31%45%9%
950
21st to endNight
11%9%31%42%7%
1045
Page generated at 2024-01-09 05:14:43. Version ac07

Copyright 2024 Attilla Danko


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