Pettigrew State Park
Clear Sky Chart
History

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

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
38%
24016
20%
74599
12%
23964
48%
23964
25%
46465

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%
757
22%
2478
8%
757
40%
757
19%
1527
January11th to 20thNight
27%
724
23%
2352
11%
724
44%
724
19%
1531
January21st to endNight
21%
792
26%
2574
9%
792
42%
792
21%
1557
February1st to 10thNight
25%
720
20%
2340
10%
720
40%
720
21%
1456
February11th to 20thNight
17%
702
20%
2106
7%
700
33%
700
17%
1384
February21st to endNight
21%
592
26%
1776
12%
592
39%
592
22%
1112
March1st to 10thNight
24%
720
25%
2030
11%
720
41%
720
30%
1222
March11th to 20thNight
23%
720
19%
1980
8%
720
35%
720
23%
1316
March21st to endNight
25%
792
22%
2121
10%
792
35%
792
25%
1385
April1st to 10thNight
24%
720
22%
1800
6%
720
35%
720
28%
1166
April11th to 20thNight
28%
711
24%
1775
8%
711
37%
711
31%
1154
April21st to endNight
33%
720
23%
1800
7%
720
40%
720
33%
1159
May1st to 10thNight
29%
720
16%
1800
5%
720
35%
720
28%
1201
May11th to 20thNight
38%
592
16%
1654
7%
592
45%
592
26%
1097
May21st to endNight
57%
388
18%
1551
17%
388
61%
388
26%
874
June1st to 10thNight
51%
360
17%
1440
18%
360
56%
360
24%
837
June11th to 20thNight
56%
360
15%
1440
13%
360
61%
360
24%
837
June21st to endNight
56%
360
16%
1440
17%
360
61%
360
24%
852
July1st to 10thNight
62%
387
14%
1437
14%
387
63%
387
21%
914
July11th to 20thNight
71%
522
13%
1566
11%
522
72%
522
31%
958
July21st to endNight
60%
591
13%
1672
10%
558
63%
558
27%
1091
August1st to 10thNight
59%
563
11%
1626
8%
560
60%
560
27%
1069
August11th to 20thNight
58%
710
14%
1774
8%
710
59%
710
28%
1237
August21st to endNight
58%
792
15%
1980
9%
792
59%
792
29%
1379
September1st to 10thNight
59%
720
20%
1800
12%
720
61%
720
30%
1224
September11th to 20thNight
52%
720
23%
1800
15%
720
55%
720
29%
1229
September21st to endNight
46%
720
18%
2026
13%
720
51%
720
23%
1407
October1st to 10thNight
51%
720
24%
2160
21%
720
59%
720
31%
1317
October11th to 20thNight
42%
720
26%
2160
19%
720
53%
720
29%
1299
October21st to endNight
42%
792
32%
2376
21%
792
57%
792
33%
1354
November1st to 10thNight
41%
740
25%
2258
17%
740
52%
740
27%
1392
November11th to 20thNight
34%
760
24%
2470
14%
760
48%
760
24%
1505
November21st to endNight
39%
760
27%
2470
18%
760
52%
760
29%
1406
December1st to 10thNight
27%
760
19%
2655
8%
760
43%
760
18%
1722
December11th to 20thNight
30%
760
23%
3174
13%
758
45%
758
19%
1841
December21st to endNight
29%
829
16%
4738
12%
817
44%
817
14%
2454

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%6%25%5%35%5%6%8%41%
74625
Night
13%6%25%5%345%5%8%44%
75058
TransparencyDay
41%6%12%22%16%3
74343
Night
39%5%12%22%17%4
74859
SeeingDay
19%12%25%25%14%5%
14252
Night
17%11%27%30%13%2
24028

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
14%6%243345%5%5%48%
1682
11th to 20thDay
15%7%244345%46%45%
1620
21st to endDay
16%8%245%34446%44%
1782
February1st to 10thDay
15%8%26%5%3345%7%42%
1620
11th to 20thDay
19%5%245%34345%44%
1740
21st to endDay
15%8%345%3445%7%41%
1480
March1st to 10thDay
13%6%24424345%52%
1926
11th to 20thDay
17%6%25%5%4346%6%42%
1980
21st to endDay
16%7%35%6%4445%7%41%
2233
April1st to 10thDay
13%5%23334446%53%
2160
11th to 20thDay
9%425%5%35%45%8%49%
2134
21st to endDay
11%5%25%5%3445%8%47%
2160
May1st to 10thDay
11%6%26%5%45%5%6%9%40%
2160
11th to 20thDay
16%5%37%6%445%7%7%36%
2250
21st to endDay
11%6%26%6%46%6%6%9%38%
2725
June1st to 10thDay
11%5%36%7%46%7%7%11%36%
2520
11th to 20thDay
10%425%6%47%7%7%11%37%
2520
21st to endDay
7%5%36%7%5%7%8%9%12%32%
2520
July1st to 10thDay
9%5%36%7%37%7%9%11%33%
2476
11th to 20thDay
9%6%37%8%47%9%8%11%29%
2340
21st to endDay
9%6%37%8%47%7%7%11%31%
2547
August1st to 10thDay
12%6%37%8%46%7%8%10%28%
2280
11th to 20thDay
10%8%27%7%5%7%7%8%9%30%
2126
21st to endDay
12%6%37%8%5%6%7%6%9%31%
2376
September1st to 10thDay
12%6%36%6%46%6%7%9%34%
2160
11th to 20thDay
14%6%26%6%46%6%5%7%37%
2160
21st to endDay
20%8%36%4345%5%7%35%
1927
October1st to 10thDay
17%6%25%5%34447%42%
1800
11th to 20thDay
14%6%25%434436%49%
1800
21st to endDay
12%6%36%434445%51%
1980
November1st to 10thDay
17%6%14424347%48%
1819
11th to 20thDay
17%5%23433346%51%
1710
21st to endDay
15%5%2442345%7%50%
1710
December1st to 10thDay
17%7%36%444447%40%
1520
11th to 20thDay
16%6%24313245%52%
1910
21st to endDay
15%6%25%434447%46%
2772
January1st to 10thNight
15%7%36%5%24346%45%
2478
11th to 20thNight
14%7%46%6%35%45%7%40%
2352
21st to endNight
17%6%25%42445%5%46%
2574
February1st to 10thNight
20%7%3432345%6%42%
2340
11th to 20thNight
20%8%25%424446%42%
2104
21st to endNight
16%7%25%42435%6%46%
1776
March1st to 10thNight
14%5%23423437%52%
2030
11th to 20thNight
16%7%36%5%2446%8%39%
1980
21st to endNight
15%5%35%5%345%5%7%43%
2121
April1st to 10thNight
13%6%345%2445%7%48%
1800
11th to 20thNight
10%6%26%5%345%5%7%47%
1775
21st to endNight
11%6%244245%5%7%48%
1800
May1st to 10thNight
12%5%35%6%35%5%5%8%43%
1800
11th to 20thNight
15%6%25%6%4446%9%40%
1653
21st to endNight
9%435%5%35%47%10%45%
1550
June1st to 10thNight
10%5%35%5%35%6%6%10%42%
1440
11th to 20thNight
8%435%5%35%8%9%13%38%
1440
21st to endNight
8%435%6%27%7%8%10%39%
1440
July1st to 10thNight
7%426%6%48%7%6%12%37%
1479
11th to 20thNight
7%5%346%35%6%7%13%41%
1620
21st to endNight
8%435%6%5%7%6%8%11%37%
1771
August1st to 10thNight
10%5%37%7%45%6%6%11%38%
1637
11th to 20thNight
8%5%38%7%45%7%7%9%37%
1774
21st to endNight
11%6%37%6%36%7%7%10%35%
1980
September1st to 10thNight
10%6%25%6%45%5%6%9%42%
1800
11th to 20thNight
13%6%36%5%245%6%9%40%
1800
21st to endNight
19%7%26%6%35%5%5%7%35%
2026
October1st to 10thNight
14%5%2443445%6%49%
2160
11th to 20thNight
15%6%24423445%51%
2160
21st to endNight
11%5%25%42345%6%53%
2376
November1st to 10thNight
15%5%25%433445%49%
2258
11th to 20thNight
17%6%24423446%46%
2470
21st to endNight
12%6%24434348%51%
2470
December1st to 10thNight
16%8%35%6%3445%5%40%
2655
11th to 20thNight
17%6%25%434446%47%
3285
21st to endNight
14%6%2442345%7%47%
4884

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
38%410%25%19%5%
1683
11th to 20thDay
41%410%22%20%3
1620
21st to endDay
43%37%22%20%5%
1782
February1st to 10thDay
42%410%23%17%3
1620
11th to 20thDay
44%38%18%21%6%
1749
21st to endDay
43%410%20%17%6%
1480
March1st to 10thDay
36%410%24%21%6%
1926
11th to 20thDay
43%49%22%16%6%
1980
21st to endDay
43%5%11%19%18%3
2233
April1st to 10thDay
33%411%23%24%5%
2160
11th to 20thDay
34%411%24%21%7%
2134
21st to endDay
35%6%12%25%19%4
2160
May1st to 10thDay
41%6%14%21%15%3
2160
11th to 20thDay
46%6%10%24%12%2
2254
21st to endDay
41%7%15%25%12%1
2725
June1st to 10thDay
42%8%14%21%14%1
2520
11th to 20thDay
39%8%19%21%12%1
2520
21st to endDay
41%9%18%20%11%1
2520
July1st to 10thDay
40%9%16%22%10%2
2408
11th to 20thDay
44%11%17%19%7%1
2271
21st to endDay
42%9%18%22%8%1
2405
August1st to 10thDay
48%8%20%17%7%
2267
11th to 20thDay
46%10%15%20%9%1
2126
21st to endDay
46%7%16%18%9%3
2376
September1st to 10thDay
45%8%14%16%14%3
2160
11th to 20thDay
45%6%10%20%17%2
2160
21st to endDay
49%49%20%15%3
1927
October1st to 10thDay
43%48%20%22%2
1800
11th to 20thDay
38%48%23%22%5%
1800
21st to endDay
36%46%21%28%5%
1980
November1st to 10thDay
38%310%20%25%4
1819
11th to 20thDay
36%39%22%23%6%
1710
21st to endDay
35%49%26%23%4
1710
December1st to 10thDay
45%411%21%15%3
1520
11th to 20thDay
37%27%27%19%8%
1906
21st to endDay
39%49%25%21%2
2772
January1st to 10thNight
42%38%22%20%5%
2478
11th to 20thNight
44%5%9%21%17%4
2352
21st to endNight
41%28%23%20%6%
2574
February1st to 10thNight
42%49%24%17%5%
2340
11th to 20thNight
45%48%17%19%6%
2106
21st to endNight
40%39%20%20%7%
1776
March1st to 10thNight
35%311%25%21%5%
2030
11th to 20thNight
43%5%11%20%16%5%
1980
21st to endNight
40%412%23%17%4
2121
April1st to 10thNight
37%412%18%24%5%
1800
11th to 20thNight
37%5%12%23%19%5%
1775
21st to endNight
35%6%12%27%18%4
1800
May1st to 10thNight
38%6%14%24%14%3
1800
11th to 20thNight
42%6%15%23%13%2
1654
21st to endNight
34%8%20%25%12%1
1551
June1st to 10thNight
37%7%16%26%13%1
1440
11th to 20thNight
34%10%22%22%11%1
1440
21st to endNight
37%8%21%23%11%
1440
July1st to 10thNight
40%11%19%19%10%2
1437
11th to 20thNight
33%9%26%24%7%
1566
21st to endNight
36%11%21%25%6%1
1672
August1st to 10thNight
40%8%25%22%5%
1626
11th to 20thNight
41%9%21%17%11%1
1774
21st to endNight
42%7%20%21%7%2
1980
September1st to 10thNight
38%9%19%18%14%2
1800
11th to 20thNight
41%7%12%22%16%2
1800
21st to endNight
47%6%11%22%13%1
2026
October1st to 10thNight
36%5%9%23%24%3
2160
11th to 20thNight
36%48%22%24%5%
2160
21st to endNight
32%37%23%28%7%
2376
November1st to 10thNight
39%47%22%24%5%
2258
11th to 20thNight
40%49%17%23%7%
2470
21st to endNight
34%39%25%23%5%
2470
December1st to 10thNight
46%412%17%17%4
2655
11th to 20thNight
40%38%20%23%6%
3288
21st to endNight
37%411%24%21%3
4884

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%28%34%12%2
258
11th to 20thDay
24%26%33%14%2
240
21st to endDay
28%26%33%10%3
264
February1st to 10thDay
27%22%37%10%4
240
11th to 20thDay
32%24%29%13%2
408
21st to endDay
27%23%30%15%41
346
March1st to 10thDay
24%18%36%16%6%1
420
11th to 20thDay
25%24%31%15%42
420
21st to endDay
23%21%35%16%6%
462
April1st to 10thDay
24%22%30%16%5%2
420
11th to 20thDay
16%18%32%22%8%4
412
21st to endDay
15%14%34%24%10%2
420
May1st to 10thDay
18%15%34%24%7%2
423
11th to 20thDay
20%5%28%32%13%2
447
21st to endDay
17%5%23%29%20%6%
485
June1st to 10thDay
14%6%28%31%16%5%
450
11th to 20thDay
12%7%19%34%20%8%
450
21st to endDay
9%423%36%22%7%
450
July1st to 10thDay
11%415%35%26%9%
445
11th to 20thDay
10%412%36%30%9%
444
21st to endDay
11%318%39%24%5%
488
August1st to 10thDay
14%5%19%32%22%8%
446
11th to 20thDay
14%312%28%30%14%
439
21st to endDay
13%316%32%25%11%
495
September1st to 10thDay
15%421%25%21%14%
450
11th to 20thDay
17%5%20%31%18%9%
450
21st to endDay
26%6%20%23%17%7%
450
October1st to 10thDay
20%6%23%26%17%8%
450
11th to 20thDay
18%11%24%27%15%4
450
21st to endDay
16%13%26%26%16%3
495
November1st to 10thDay
22%11%29%23%12%4
437
11th to 20thDay
20%16%30%23%9%2
370
21st to endDay
21%16%23%22%17%2
370
December1st to 10thDay
25%25%31%13%6%1
180
11th to 20thDay
24%22%28%17%9%
180
21st to endDay
21%20%30%18%10%1
198
January1st to 10thNight
21%22%29%23%5%
760
11th to 20thNight
20%17%31%25%7%
724
21st to endNight
21%19%34%21%4
792
February1st to 10thNight
23%18%32%25%3
720
11th to 20thNight
28%22%31%17%2
703
21st to endNight
22%20%33%21%4
592
March1st to 10thNight
20%15%38%21%5%
720
11th to 20thNight
22%14%38%21%5%
720
21st to endNight
19%20%32%23%5%
792
April1st to 10thNight
18%19%37%22%4
720
11th to 20thNight
14%15%40%23%7%
711
21st to endNight
15%11%38%29%6%1
720
May1st to 10thNight
15%13%38%27%6%
720
11th to 20thNight
18%8%29%34%10%
592
21st to endNight
11%420%45%19%1
389
June1st to 10thNight
13%324%43%15%1
360
11th to 20thNight
9%323%42%20%3
360
21st to endNight
9%320%51%17%
360
July1st to 10thNight
8%215%46%25%3
387
11th to 20thNight
8%111%44%29%7%
522
21st to endNight
10%316%41%26%3
591
August1st to 10thNight
14%211%42%28%4
563
11th to 20thNight
9%214%41%28%6%
710
21st to endNight
13%313%35%30%6%
792
September1st to 10thNight
12%316%34%28%8%
720
11th to 20thNight
16%417%36%24%4
720
21st to endNight
23%317%33%20%3
720
October1st to 10thNight
16%422%30%24%4
720
11th to 20thNight
20%8%25%29%16%2
720
21st to endNight
15%10%27%29%17%3
792
November1st to 10thNight
19%9%25%30%14%3
740
11th to 20thNight
22%13%27%26%11%1
760
21st to endNight
16%14%28%26%16%1
760
December1st to 10thNight
22%15%29%27%7%
760
11th to 20thNight
19%14%31%28%8%
760
21st to endNight
19%17%29%28%7%
836
Page generated at 2024-01-08 11:14:19. Version ac07

Copyright 2024 Attilla Danko


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