Weiser Memorial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weiser Memorial Park clear sky chart from 2005-11-05 to 2017-12-20.

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
51%
15106
18%
48026
15%
15080
56%
15080
24%
29958

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
38%
716
6%
2506
5%
716
40%
716
8%
2009
January16th to endNight
40%
768
8%
2688
7%
768
42%
768
11%
2031
February1st to 15thNight
41%
702
7%
2277
6%
700
44%
700
14%
1666
February16th to endNight
43%
632
12%
1895
11%
632
47%
632
16%
1373
March1st to 15thNight
43%
720
10%
2160
8%
720
46%
720
17%
1567
March16th to endNight
42%
768
14%
2027
8%
768
46%
768
20%
1443
April1st to 15thNight
48%
719
18%
1799
9%
719
51%
719
28%
1223
April16th to endNight
45%
585
22%
1665
13%
585
51%
585
28%
1000
May1st to 15thNight
50%
496
22%
1576
15%
496
58%
496
32%
813
May16th to endNight
53%
374
18%
1496
22%
374
61%
374
24%
813
June1st to 15thNight
46%
360
14%
1440
16%
360
56%
360
23%
791
June16th to endNight
53%
360
23%
1440
23%
360
70%
360
37%
617
July1st to 15thNight
66%
340
23%
1360
30%
340
77%
340
50%
496
July16th to endNight
60%
376
34%
1416
36%
354
80%
354
55%
484
August1st to 15thNight
69%
444
31%
1516
27%
442
76%
442
50%
639
August16th to endNight
75%
715
38%
1861
22%
715
80%
715
62%
875
September1st to 15thNight
73%
720
36%
1828
21%
720
77%
720
61%
905
September16th to endNight
66%
716
34%
1980
26%
716
72%
716
41%
1095
October1st to 15thNight
58%
720
26%
2045
20%
720
64%
720
36%
1152
October16th to endNight
61%
768
25%
2490
24%
768
66%
768
26%
1473
November1st to 15thNight
53%
760
18%
2470
19%
760
55%
760
21%
1624
November16th to endNight
43%
780
12%
2607
10%
780
48%
780
16%
1767
December1st to 15thNight
43%
780
9%
2730
7%
780
46%
780
12%
2016
December16th to endNight
38%
787
10%
2754
8%
787
41%
787
11%
2086

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
8%5%25%424446%49%
48833
Night
10%6%25%42445%6%46%
48196
Cloud CoverDay
9%5%24424446%50%
48834
Night
11%6%25%424446%47%
48199
TransparencyDay
34%6%12%19%17%9%
48505
Night
38%6%12%19%14%7%
48027
SeeingDay
10%12%16%27%23%9%
5675
Night
12%15%12%33%22%3
15114

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 15thDay
16%11%5%9%8%45%5%5%5%22%
1432
16th to endDay
17%14%5%12%7%3445%6%18%
1536
February1st to 15thDay
14%11%47%7%45%35%6%28%
1584
16th to endDay
12%6%37%7%35%45%8%32%
1579
March1st to 15thDay
12%9%48%6%35%5%6%6%29%
1800
16th to endDay
12%8%36%5%35%5%6%6%36%
2195
April1st to 15thDay
7%6%45%6%35%5%6%7%41%
2149
16th to endDay
8%5%24424447%50%
2293
May1st to 15thDay
5%41342345%9%55%
2373
16th to endDay
6%5%35%5%25%45%8%46%
2615
June1st to 15thDay
7%4244346%6%7%47%
2520
16th to endDay
3212312336%68%
2520
July1st to 15thDay
2212213245%71%
2520
16th to endDay
11112225%80%
2657
August1st to 15thDay
2212222336%70%
2435
16th to endDay
122212235%74%
2339
September1st to 15thDay
221221223474%
2131
16th to endDay
5%314323446%60%
1980
October1st to 15thDay
8%414324346%55%
1914
16th to endDay
9%7%36%6%345%5%6%42%
1734
November1st to 15thDay
14%6%26%5%35%5%5%7%37%
1719
16th to endDay
14%8%37%6%37%5%47%29%
1680
December1st to 15thDay
17%11%5%11%6%35%5%46%23%
1560
16th to endDay
20%11%410%7%45%44422%
1568
January1st to 15thNight
17%11%5%10%6%35%445%24%
2506
16th to endNight
15%10%5%9%6%3445%6%28%
2688
February1st to 15thNight
14%10%46%6%345%5%6%32%
2266
16th to endNight
12%9%36%6%36%5%6%7%31%
1895
March1st to 15thNight
14%9%46%6%35%45%6%34%
2160
16th to endNight
11%8%36%6%345%5%7%35%
2024
April1st to 15thNight
10%5%36%5%35%5%47%44%
1799
16th to endNight
7%6%244245%5%7%50%
1665
May1st to 15thNight
5%21432445%6%59%
1576
16th to endNight
5%5%245%35%5%7%10%44%
1496
June1st to 15thNight
7%425%436%35%7%49%
1440
16th to endNight
322331245%6%64%
1440
July1st to 15thNight
11213346%72%
1440
16th to endNight
12121223478%
1512
August1st to 15thNight
1112223349%67%
1524
16th to endNight
112112335%75%
1861
September1st to 15thNight
222111335%74%
1828
16th to endNight
7%314323435%61%
1980
October1st to 15thNight
7%424423446%56%
2045
16th to endNight
9%424434446%49%
2490
November1st to 15thNight
15%6%245%345%6%7%39%
2470
16th to endNight
16%7%36%43345%5%38%
2607
December1st to 15thNight
16%8%38%5%35%45%5%32%
2730
16th to endNight
20%10%48%6%345%45%26%
2754

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
17%10%49%8%36%45%6%23%
1432
16th to endDay
18%13%5%11%7%2445%6%19%
1536
February1st to 15thDay
16%11%46%6%34446%31%
1584
16th to endDay
12%7%36%6%45%5%6%7%34%
1579
March1st to 15thDay
12%9%47%6%35%5%6%7%30%
1800
16th to endDay
13%8%35%5%35%5%5%8%36%
2196
April1st to 15thDay
8%7%25%5%446%5%8%40%
2149
16th to endDay
8%5%245%24446%51%
2293
May1st to 15thDay
5%41233336%8%56%
2373
16th to endDay
8%5%35%5%2436%8%46%
2615
June1st to 15thDay
8%434435%46%7%47%
2520
16th to endDay
3212313345%68%
2520
July1st to 15thDay
322122245%72%
2520
16th to endDay
1111223480%
2657
August1st to 15thDay
2212212335%71%
2435
16th to endDay
21221222475%
2339
September1st to 15thDay
2211212235%75%
2131
16th to endDay
6%313313346%61%
1980
October1st to 15thDay
8%413324346%56%
1914
16th to endDay
10%6%26%5%35%45%6%43%
1734
November1st to 15thDay
15%7%245%245%5%7%39%
1719
16th to endDay
17%7%36%6%35%447%33%
1680
December1st to 15thDay
18%9%410%7%34446%25%
1560
16th to endDay
21%10%410%6%3444424%
1568
January1st to 15thNight
18%12%49%7%33436%25%
2506
16th to endNight
16%10%49%6%34347%29%
2688
February1st to 15thNight
16%10%36%5%24446%34%
2266
16th to endNight
14%8%37%5%35%5%6%7%32%
1895
March1st to 15thNight
14%9%37%5%45%346%35%
2160
16th to endNight
13%8%35%6%3445%7%36%
2027
April1st to 15thNight
11%5%26%5%25%5%45%45%
1799
16th to endNight
8%6%1433446%5%52%
1665
May1st to 15thNight
5%21432345%7%59%
1576
16th to endNight
6%425%4345%6%9%47%
1496
June1st to 15thNight
8%424424447%51%
1440
16th to endNight
421331245%6%64%
1440
July1st to 15thNight
1122325%6%73%
1440
16th to endNight
11211223478%
1512
August1st to 15thNight
22221325%7%68%
1524
16th to endNight
112112235%76%
1861
September1st to 15thNight
22221123475%
1828
16th to endNight
7%323423335%61%
1980
October1st to 15thNight
8%314314345%57%
2045
16th to endNight
10%4245%3445%6%49%
2490
November1st to 15thNight
17%6%15%42445%7%40%
2470
16th to endNight
18%7%25%5%23445%39%
2607
December1st to 15thNight
17%8%37%5%35%45%5%33%
2730
16th to endNight
21%10%48%5%34446%27%
2754

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
63%12%12%10%
1432
16th to endDay
67%9%12%8%1
1536
February1st to 15thDay
54%13%14%14%2
1584
16th to endDay
47%11%18%17%4
1579
March1st to 15thDay
51%8%15%17%5%
1800
16th to endDay
46%7%16%21%7%
2196
April1st to 15thDay
40%6%16%25%9%1
2149
16th to endDay
34%5%12%28%17%2
2293
May1st to 15thDay
25%411%31%21%4
2373
16th to endDay
35%5%14%24%16%3
2619
June1st to 15thDay
34%7%12%20%20%5%
2520
16th to endDay
18%37%21%31%16%
2520
July1st to 15thDay
15%25%15%29%32%
2371
16th to endDay
8%1411%29%45%
2490
August1st to 15thDay
14%46%15%31%27%
2418
16th to endDay
14%2417%35%24%
2339
September1st to 15thDay
13%26%21%35%20%
2131
16th to endDay
25%49%30%24%6%
1980
October1st to 15thDay
29%5%15%26%20%2
1914
16th to endDay
41%6%15%25%11%
1734
November1st to 15thDay
43%10%19%19%6%
1719
16th to endDay
50%8%18%16%5%
1680
December1st to 15thDay
59%10%16%10%2
1560
16th to endDay
63%7%13%12%3
1568
January1st to 15thNight
61%10%13%11%2
2506
16th to endNight
55%9%16%15%3
2688
February1st to 15thNight
51%9%20%14%4
2277
16th to endNight
49%9%16%19%5%
1895
March1st to 15thNight
50%8%13%20%5%1
2160
16th to endNight
46%7%14%24%7%
2027
April1st to 15thNight
40%6%13%24%14%
1799
16th to endNight
32%5%12%26%20%2
1665
May1st to 15thNight
23%5%11%28%26%4
1577
16th to endNight
32%6%12%31%13%4
1496
June1st to 15thNight
33%5%13%23%18%4
1440
16th to endNight
19%48%21%30%15%
1440
July1st to 15thNight
12%36%18%29%30%
1360
16th to endNight
11%1311%27%44%
1416
August1st to 15thNight
14%37%15%28%30%
1516
16th to endNight
12%25%16%32%31%
1861
September1st to 15thNight
13%2418%32%28%
1828
16th to endNight
26%36%22%25%15%
1980
October1st to 15thNight
28%410%27%23%5%
2045
16th to endNight
34%6%13%24%19%1
2490
November1st to 15thNight
43%6%15%22%10%
2470
16th to endNight
47%6%18%19%7%
2607
December1st to 15thNight
52%11%16%15%5%
2730
16th to endNight
58%7%16%14%3
2754

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
33%111%21%16%15%
60
16th to endDay
39%36%25%17%9%
64
February1st to 15thDay
22%10%11%24%21%9%
179
16th to endDay
18%14%16%29%13%6%
238
March1st to 15thDay
22%15%16%26%15%2
270
16th to endDay
17%19%20%28%12%1
288
April1st to 15thDay
7%20%26%19%17%8%
269
16th to endDay
8%20%26%24%14%4
270
May1st to 15thDay
7%22%22%23%18%4
288
16th to endDay
8%15%16%25%23%12%
330
June1st to 15thDay
6%17%23%23%20%7%
315
16th to endDay
5%15%17%29%23%8%
315
July1st to 15thDay
49%12%33%29%10%
305
16th to endDay
111%16%35%28%6%
327
August1st to 15thDay
36%15%29%34%10%
315
16th to endDay
36%11%25%32%21%
332
September1st to 15thDay
46%13%21%32%20%
315
16th to endDay
7%7%13%26%29%15%
315
October1st to 15thDay
11%11%13%29%23%10%
315
16th to endDay
17%113%30%26%11%
150
November1st to 15thDay
17%20%34%26%1
135
16th to endDay
32%20%31%13%1
118
December1st to 15thDay
30%18%30%16%13%
90
16th to endDay
27%215%19%29%5%
72
January1st to 15thNight
17%18%8%28%22%4
720
16th to endNight
18%17%6%28%23%4
768
February1st to 15thNight
19%17%10%29%19%3
704
16th to endNight
16%16%14%32%16%2
632
March1st to 15thNight
16%19%12%31%18%2
720
16th to endNight
16%19%13%36%12%1
768
April1st to 15thNight
9%19%14%31%22%2
719
16th to endNight
10%19%19%30%17%2
585
May1st to 15thNight
5%21%17%32%18%2
497
16th to endNight
5%20%12%31%25%4
375
June1st to 15thNight
8%18%18%29%21%2
360
16th to endNight
5%18%20%33%21%1
360
July1st to 15thNight
13%15%44%24%2
340
16th to endNight
117%16%39%24%1
376
August1st to 15thNight
210%13%36%33%2
444
16th to endNight
310%8%39%34%4
715
September1st to 15thNight
39%10%35%35%6%
720
16th to endNight
8%9%8%32%33%7%
716
October1st to 15thNight
10%10%14%36%25%3
720
16th to endNight
12%9%9%38%25%5%
768
November1st to 15thNight
15%13%9%36%23%1
760
16th to endNight
19%16%10%30%19%3
780
December1st to 15thNight
18%16%10%33%18%2
780
16th to endNight
21%16%11%34%14%1
787
Page generated at 2017-12-21 05:04:50. Version ac04

Copyright 2017 A. Danko


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