Deer Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deer 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
49%
22953
14%
74962
13%
22912
52%
22912
20%
51039

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
25%
760
6%
2646
5%
756
27%
756
7%
2218
January11th to 20thNight
30%
726
5%
2540
4%
726
32%
726
7%
2087
January21st to endNight
31%
792
6%
2772
5%
792
33%
792
9%
2254
February1st to 10thNight
36%
720
9%
2520
7%
720
40%
720
12%
1922
February11th to 20thNight
39%
704
10%
2174
7%
700
43%
700
16%
1610
February21st to endNight
42%
592
16%
1776
15%
592
46%
592
19%
1262
March1st to 10thNight
42%
720
11%
2160
10%
720
45%
720
17%
1567
March11th to 20thNight
45%
720
14%
2116
11%
720
48%
720
20%
1504
March21st to endNight
43%
792
10%
1995
5%
792
44%
792
20%
1502
April1st to 10thNight
51%
720
14%
1800
7%
720
52%
720
25%
1272
April11th to 20thNight
44%
651
17%
1719
10%
651
47%
651
26%
1187
April21st to endNight
49%
540
16%
1620
13%
540
53%
540
24%
1077
May1st to 10thNight
60%
395
18%
1475
21%
395
65%
395
27%
828
May11th to 20thNight
62%
354
16%
1416
27%
354
64%
354
24%
812
May21st to endNight
60%
388
12%
1530
17%
388
61%
388
23%
905
June1st to 10thNight
60%
360
11%
1260
13%
360
62%
360
25%
768
June11th to 20thNight
52%
360
10%
1260
8%
360
55%
360
24%
775
June21st to endNight
72%
360
15%
1260
16%
360
74%
360
39%
629
July1st to 10thNight
81%
350
17%
1361
23%
350
84%
350
51%
547
July11th to 20thNight
78%
348
23%
1392
35%
348
84%
348
56%
515
July21st to endNight
88%
394
31%
1488
50%
372
92%
372
68%
483
August1st to 10thNight
80%
358
31%
1424
42%
356
85%
356
54%
535
August11th to 20thNight
82%
449
33%
1517
35%
449
83%
449
54%
659
August21st to endNight
76%
738
31%
1926
21%
738
78%
738
54%
1007
September1st to 10thNight
76%
720
30%
1800
17%
720
78%
720
57%
952
September11th to 20thNight
68%
720
27%
1894
19%
720
70%
720
42%
1126
September21st to endNight
62%
720
25%
1980
21%
720
65%
720
38%
1182
October1st to 10thNight
59%
720
20%
2056
18%
720
62%
720
32%
1259
October11th to 20thNight
56%
720
20%
2264
19%
720
60%
720
28%
1408
October21st to endNight
49%
792
18%
2574
18%
792
53%
792
23%
1680
November1st to 10thNight
40%
740
9%
2405
9%
740
42%
740
14%
1804
November11th to 20thNight
37%
760
9%
2578
7%
760
40%
760
11%
1983
November21st to endNight
38%
878
6%
2778
5%
878
40%
878
12%
2169
December1st to 10thNight
36%
950
8%
2850
6%
950
39%
950
12%
2259
December11th to 20thNight
27%
949
2%
3505
2%
949
28%
949
5%
3074
December21st to endNight
22%
993
4%
5131
4%
984
25%
984
4%
4218

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%8%36%5%3445%6%41%
74557
Night
15%9%46%5%3445%6%38%
75163
TransparencyDay
43%7%13%20%14%4
74259
Night
46%8%12%17%12%4
74979
SeeingDay
15%11%24%27%18%5%
13679
Night
19%5%17%35%22%3
22965

By Month

Percentage Cloud Cover NW (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
29%17%5%7%6%345%45%16%
1519
11th to 20thDay
23%18%9%11%7%4432415%
1448
21st to endDay
20%18%7%10%7%35%35%5%17%
1584
February1st to 10thDay
22%12%5%9%7%45%346%22%
1440
11th to 20thDay
15%14%5%7%7%4445%6%28%
1672
21st to endDay
16%13%6%7%7%345%5%5%29%
1480
March1st to 10thDay
18%12%5%8%7%35%46%6%27%
1800
11th to 20thDay
18%10%47%6%345%5%6%32%
1844
21st to endDay
18%13%48%7%35%45%7%25%
2358
April1st to 10thDay
16%9%47%7%46%7%7%8%27%
2160
11th to 20thDay
13%8%36%7%445%6%7%37%
2192
21st to endDay
10%8%37%7%5%6%5%6%8%36%
2340
May1st to 10thDay
7%6%36%6%45%6%6%8%44%
2484
11th to 20thDay
11%6%26%6%46%6%7%8%39%
2477
21st to endDay
11%7%37%6%46%6%7%9%36%
2741
June1st to 10thDay
16%7%36%6%3445%7%41%
2700
11th to 20thDay
13%6%36%6%35%6%6%8%38%
2700
21st to endDay
6%42443445%6%58%
2700
July1st to 10thDay
4213424446%65%
2554
11th to 20thDay
4213323445%70%
2520
21st to endDay
111221223480%
2741
August1st to 10thDay
321232335%7%69%
2507
11th to 20thDay
4212322347%69%
2382
21st to endDay
5%41443445%7%60%
2426
September1st to 10thDay
5%323323446%66%
2160
11th to 20thDay
8%413435%5%5%7%55%
2065
21st to endDay
9%425%5%345%6%8%48%
1980
October1st to 10thDay
12%7%35%6%24347%47%
1900
11th to 20thDay
13%7%25%5%25%46%8%43%
1695
21st to endDay
21%8%26%5%25%45%7%36%
1782
November1st to 10thDay
24%12%46%6%33446%27%
1674
11th to 20thDay
23%12%5%8%6%34445%26%
1601
21st to endDay
21%16%5%11%6%345%45%19%
1380
December1st to 10thDay
20%13%7%11%7%34435%20%
1330
11th to 20thDay
26%23%7%10%6%3433312%
1682
21st to endDay
20%22%6%8%5%345%5%5%15%
2539
January1st to 10thNight
29%16%5%7%6%34445%17%
2646
11th to 20thNight
24%16%5%9%6%33446%20%
2540
21st to endNight
18%18%6%10%6%45%445%21%
2772
February1st to 10thNight
18%15%5%7%6%345%46%27%
2520
11th to 20thNight
16%11%48%6%35%6%5%5%30%
2172
21st to endNight
12%11%47%7%4445%7%34%
1776
March1st to 10thNight
17%10%37%6%35%5%47%31%
2160
11th to 20thNight
17%8%36%6%35%45%7%35%
2115
21st to endNight
15%9%47%7%46%6%7%8%28%
1995
April1st to 10thNight
11%8%46%7%46%5%6%8%36%
1800
11th to 20thNight
12%9%35%8%45%446%40%
1719
21st to endNight
10%7%36%6%46%5%6%7%40%
1620
May1st to 10thNight
8%5%25%45%5%6%7%9%44%
1475
11th to 20thNight
9%5%25%5%35%5%6%9%44%
1416
21st to endNight
10%6%36%5%35%6%9%8%40%
1530
June1st to 10thNight
13%5%26%5%345%6%9%42%
1260
11th to 20thNight
10%5%347%46%5%7%7%42%
1260
21st to endNight
6%4243335%7%7%57%
1260
July1st to 10thNight
2312323348%68%
1401
11th to 20thNight
2112223447%73%
1440
21st to endNight
12223235%81%
1576
August1st to 10thNight
3312223347%72%
1432
11th to 20thNight
331232335%6%70%
1517
21st to endNight
321332446%8%63%
1926
September1st to 10thNight
42122235%6%7%66%
1800
11th to 20thNight
7%325%5%3446%8%53%
1894
21st to endNight
10%5%2443445%7%53%
1980
October1st to 10thNight
11%5%25%6%34346%50%
2056
11th to 20thNight
13%5%35%5%3445%7%47%
2264
21st to endNight
17%6%25%4345%5%6%42%
2574
November1st to 10thNight
22%11%46%6%245%5%7%28%
2405
11th to 20thNight
20%10%47%6%45%5%5%6%28%
2578
21st to endNight
22%12%47%7%35%446%26%
2778
December1st to 10thNight
18%13%6%9%6%3445%5%26%
2850
11th to 20thNight
25%19%6%9%6%3445%5%15%
3510
21st to endNight
22%17%5%11%7%445%45%16%
5146

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
70%10%9%8%3
1519
11th to 20thDay
74%9%9%6%2
1448
21st to endDay
70%8%10%9%31
1584
February1st to 10thDay
63%9%13%9%5%1
1440
11th to 20thDay
56%12%14%13%6%
1681
21st to endDay
57%9%12%14%7%
1480
March1st to 10thDay
57%9%15%14%5%1
1800
11th to 20thDay
53%6%16%19%6%
1844
21st to endDay
59%9%17%12%3
2358
April1st to 10thDay
54%8%16%17%5%1
2160
11th to 20thDay
45%7%19%17%10%1
2192
21st to endDay
45%8%17%20%9%2
2340
May1st to 10thDay
34%8%17%27%12%1
2484
11th to 20thDay
40%9%16%23%11%
2480
21st to endDay
41%10%17%24%8%1
2742
June1st to 10thDay
43%6%13%22%14%2
2700
11th to 20thDay
40%9%14%23%11%3
2700
21st to endDay
26%6%14%29%20%5%
2700
July1st to 10thDay
20%5%10%25%27%13%
2485
11th to 20thDay
17%49%21%34%15%
2445
21st to endDay
9%35%22%44%17%
2589
August1st to 10thDay
16%410%25%31%14%
2490
11th to 20thDay
15%411%28%34%8%
2382
21st to endDay
22%6%10%29%28%5%
2426
September1st to 10thDay
20%5%12%29%25%9%
2160
11th to 20thDay
27%8%13%24%23%4
2065
21st to endDay
32%10%18%25%11%4
1980
October1st to 10thDay
38%6%14%29%11%1
1900
11th to 20thDay
39%8%15%28%9%1
1695
21st to endDay
49%9%16%19%6%
1782
November1st to 10thDay
59%9%15%14%41
1674
11th to 20thDay
61%10%11%11%42
1601
21st to endDay
66%10%11%9%3
1380
December1st to 10thDay
68%7%12%10%4
1330
11th to 20thDay
80%7%7%5%2
1684
21st to endDay
68%9%12%7%3
2539
January1st to 10thNight
70%7%10%9%21
2646
11th to 20thNight
66%9%14%9%1
2540
21st to endNight
65%9%13%9%31
2772
February1st to 10thNight
58%9%14%12%6%1
2520
11th to 20thNight
53%9%18%13%7%
2174
21st to endNight
49%8%14%18%10%1
1776
March1st to 10thNight
51%8%16%17%7%1
2160
11th to 20thNight
49%7%14%20%10%
2116
21st to endNight
51%9%15%17%7%1
1995
April1st to 10thNight
44%8%15%23%10%1
1800
11th to 20thNight
44%6%12%21%15%2
1719
21st to endNight
41%8%13%23%14%2
1620
May1st to 10thNight
33%7%14%28%15%2
1475
11th to 20thNight
35%8%14%25%16%2
1416
21st to endNight
37%8%15%28%11%1
1530
June1st to 10thNight
38%7%11%21%19%4
1260
11th to 20thNight
38%8%13%20%16%4
1260
21st to endNight
25%5%11%26%25%8%
1260
July1st to 10thNight
16%37%23%32%19%
1361
11th to 20thNight
12%49%21%28%27%
1392
21st to endNight
8%2417%39%31%
1488
August1st to 10thNight
14%36%17%36%24%
1424
11th to 20thNight
15%47%23%35%15%
1517
21st to endNight
17%6%10%23%32%12%
1926
September1st to 10thNight
17%5%8%27%29%13%
1800
11th to 20thNight
28%6%10%22%25%9%
1894
21st to endNight
30%6%15%27%16%6%
1980
October1st to 10thNight
36%5%10%31%18%1
2056
11th to 20thNight
37%7%15%25%15%1
2264
21st to endNight
42%8%14%25%10%1
2574
November1st to 10thNight
54%10%15%15%5%1
2405
11th to 20thNight
57%10%14%12%5%2
2578
21st to endNight
59%9%15%12%5%
2778
December1st to 10thNight
60%9%13%15%4
2850
11th to 20thNight
71%11%10%6%2
3507
21st to endNight
67%11%12%7%3
5146

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
33%9%21%20%13%4
180
11th to 20thDay
35%9%16%20%13%7%
162
21st to endDay
32%7%24%23%12%2
176
February1st to 10thDay
26%11%32%23%6%1
160
11th to 20thDay
24%14%26%22%11%2
378
21st to endDay
19%14%25%26%14%1
346
March1st to 10thDay
22%17%28%20%9%3
420
11th to 20thDay
20%14%23%22%18%3
420
21st to endDay
23%17%25%24%9%2
462
April1st to 10thDay
20%15%28%22%11%5%
420
11th to 20thDay
19%22%25%18%11%4
412
21st to endDay
12%16%28%28%14%3
420
May1st to 10thDay
11%11%31%29%15%3
423
11th to 20thDay
17%10%25%25%17%6%
448
21st to endDay
13%10%22%29%18%8%
503
June1st to 10thDay
17%10%23%25%20%5%
630
11th to 20thDay
14%13%30%27%13%3
630
21st to endDay
5%7%24%30%27%7%
630
July1st to 10thDay
38%27%35%24%3
480
11th to 20thDay
5%9%27%36%17%6%
444
21st to endDay
35%25%36%22%8%
487
August1st to 10thDay
5%6%20%34%26%9%
447
11th to 20thDay
4421%28%30%12%
437
21st to endDay
7%8%22%28%24%10%
495
September1st to 10thDay
7%6%25%30%25%8%
450
11th to 20thDay
9%11%22%26%25%7%
450
21st to endDay
12%12%26%26%17%7%
450
October1st to 10thDay
13%10%23%29%20%6%
450
11th to 20thDay
17%11%19%26%20%8%
345
21st to endDay
27%8%21%29%12%4
297
November1st to 10thDay
30%8%18%31%13%1
270
11th to 20thDay
32%10%17%26%13%4
219
21st to endDay
29%6%18%26%18%3
180
December1st to 10thDay
29%8%22%23%11%6%
180
11th to 20thDay
32%10%22%24%10%2
180
21st to endDay
32%14%18%24%11%2
198
January1st to 10thNight
37%7%17%26%11%2
760
11th to 20thNight
29%7%18%29%14%3
726
21st to endNight
27%419%32%17%1
792
February1st to 10thNight
25%7%22%32%13%2
720
11th to 20thNight
22%7%21%33%15%2
704
21st to endNight
17%8%20%33%19%2
592
March1st to 10thNight
22%7%19%33%18%2
720
11th to 20thNight
21%8%17%33%20%1
720
21st to endNight
20%6%19%37%15%2
792
April1st to 10thNight
15%6%17%39%21%2
720
11th to 20thNight
15%6%25%37%15%2
651
21st to endNight
14%5%24%36%20%2
540
May1st to 10thNight
9%6%18%38%27%2
395
11th to 20thNight
11%5%13%30%33%7%
354
21st to endNight
13%417%33%28%5%
389
June1st to 10thNight
13%5%15%42%23%2
360
11th to 20thNight
11%5%22%36%23%2
360
21st to endNight
8%211%46%29%4
360
July1st to 10thNight
329%43%39%3
350
11th to 20thNight
2314%47%33%1
348
21st to endNight
128%42%45%3
394
August1st to 10thNight
4110%36%43%5%
358
11th to 20thNight
238%35%43%9%
449
21st to endNight
3311%39%40%3
738
September1st to 10thNight
5%212%43%32%6%
720
11th to 20thNight
7%312%32%38%7%
720
21st to endNight
11%417%35%29%5%
720
October1st to 10thNight
13%414%38%29%2
720
11th to 20thNight
14%5%16%35%26%4
720
21st to endNight
20%321%37%16%3
792
November1st to 10thNight
27%7%17%36%13%
740
11th to 20thNight
26%7%21%30%15%2
760
21st to endNight
27%8%14%32%17%2
878
December1st to 10thNight
25%6%16%35%16%2
950
11th to 20thNight
34%6%16%32%12%
950
21st to endNight
36%7%16%31%10%
1003
Page generated at 2024-01-09 04:14:42. Version ac07

Copyright 2024 Attilla Danko


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