Pense
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pense clear sky chart from 2005-11-05 to 2017-10-16.

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
40%
15913
13%
46999
8%
15875
44%
15875
21%
32564

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
33%
895
8%
2655
5%
895
36%
895
15%
1995
January16th to endNight
24%
960
11%
2688
5%
960
30%
960
14%
2085
February1st to 15thNight
31%
789
9%
2381
6%
789
36%
789
14%
1804
February16th to endNight
38%
632
11%
1981
8%
632
43%
632
16%
1492
March1st to 15thNight
36%
720
13%
2154
8%
720
41%
720
20%
1537
March16th to endNight
33%
663
12%
2007
9%
663
38%
663
15%
1519
April1st to 15thNight
39%
539
16%
1798
12%
539
47%
539
24%
1123
April16th to endNight
39%
540
14%
1564
9%
540
44%
540
22%
1109
May1st to 15thNight
45%
539
12%
1440
6%
539
48%
539
27%
966
May16th to endNight
40%
563
9%
1474
5%
561
42%
561
24%
1049
June1st to 15thNight
42%
402
4%
1122
3%
402
44%
402
27%
732
June16th to endNight
48%
360
3%
1080
3%
360
50%
360
28%
686
July1st to 15thNight
62%
340
5%
1142
7%
340
64%
340
35%
617
July16th to endNight
64%
547
14%
1399
8%
514
67%
514
47%
759
August1st to 15thNight
65%
539
16%
1432
10%
536
69%
536
44%
824
August16th to endNight
60%
573
25%
1762
19%
573
66%
573
42%
940
September1st to 15thNight
56%
540
18%
1800
17%
540
60%
540
32%
1029
September16th to endNight
50%
561
24%
1947
22%
561
58%
561
31%
1081
October1st to 15thNight
40%
720
18%
2160
12%
720
46%
720
27%
1398
October16th to endNight
39%
856
17%
2272
8%
856
43%
856
24%
1580
November1st to 15thNight
35%
875
15%
2411
7%
875
40%
875
21%
1716
November16th to endNight
31%
900
13%
2599
7%
900
37%
900
17%
1943
December1st to 15thNight
27%
900
5%
2700
4%
900
29%
900
10%
2228
December16th to endNight
31%
960
9%
3031
6%
960
35%
960
12%
2352

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
11%8%46%6%35%5%5%7%35%
48433
Night
9%9%47%6%35%5%5%7%35%
47157
Cloud CoverDay
11%8%47%6%35%5%5%7%35%
48434
Night
9%9%47%6%35%45%7%35%
47159
TransparencyDay
47%6%15%22%7%
48095
Night
47%6%15%21%8%
46999
SeeingDay
14%7%26%29%17%4
6300
Night
13%6%28%34%14%1
15927

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
9%10%6%11%8%45%6%6%7%23%
1280
16th to endDay
5%12%6%11%9%46%5%5%7%23%
1536
February1st to 15thDay
10%12%7%10%8%5%8%6%4420%
1491
16th to endDay
7%14%7%11%10%46%7%6%5%17%
1492
March1st to 15thDay
7%13%7%10%9%45%5%6%6%21%
1803
16th to endDay
11%12%47%6%36%6%6%8%25%
2216
April1st to 15thDay
10%8%36%6%36%5%7%8%34%
2150
16th to endDay
16%11%47%6%35%445%31%
2394
May1st to 15thDay
12%7%35%5%35%5%5%6%38%
2511
16th to endDay
19%6%25%6%35%46%7%30%
2637
June1st to 15thDay
19%6%36%5%35%45%7%31%
2835
16th to endDay
13%6%35%5%35%5%6%9%35%
2880
July1st to 15thDay
8%3244345%6%8%48%
2745
16th to endDay
6%32432445%9%53%
2671
August1st to 15thDay
9%5%15%435%45%8%46%
2520
16th to endDay
9%413423348%53%
2438
September1st to 15thDay
12%5%25%323446%48%
2160
16th to endDay
13%42442345%8%47%
2011
October1st to 15thDay
16%10%45%423336%37%
1800
16th to endDay
12%11%47%6%33346%34%
1609
November1st to 15thDay
9%9%6%8%6%34347%34%
1447
16th to endDay
12%11%5%7%8%46%5%5%6%26%
1359
December1st to 15thDay
9%15%8%12%11%47%6%4413%
1260
16th to endDay
8%14%8%10%9%5%6%6%47%18%
1188
January1st to 15thNight
8%11%5%9%7%47%6%6%6%27%
2655
16th to endNight
6%13%6%10%8%47%5%6%7%24%
2688
February1st to 15thNight
7%11%6%10%10%45%5%45%26%
2370
16th to endNight
7%10%412%8%46%6%6%7%24%
1981
March1st to 15thNight
7%9%5%8%7%35%5%6%7%31%
2154
16th to endNight
12%11%5%9%7%46%45%6%26%
2004
April1st to 15thNight
9%7%35%5%345%6%8%40%
1798
16th to endNight
14%10%45%425%6%5%7%33%
1564
May1st to 15thNight
11%9%34435%448%39%
1439
16th to endNight
17%5%25%43446%7%35%
1474
June1st to 15thNight
15%6%3432446%7%41%
1122
16th to endNight
10%5%24425%46%9%42%
1080
July1st to 15thNight
6%32441445%8%53%
1212
16th to endNight
5%21323335%10%58%
1494
August1st to 15thNight
7%2123235%6%8%56%
1440
16th to endNight
7%423213348%57%
1762
September1st to 15thNight
10%41432445%7%50%
1800
16th to endNight
11%423423447%51%
1947
October1st to 15thNight
14%8%34333447%42%
2160
16th to endNight
10%11%46%6%34446%37%
2272
November1st to 15thNight
12%10%46%5%25%447%36%
2411
16th to endNight
10%13%49%6%36%45%7%28%
2599
December1st to 15thNight
10%14%7%11%9%5%6%5%46%17%
2700
16th to endNight
8%12%6%11%10%46%6%5%7%21%
3031

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
9%9%6%12%8%5%5%6%5%8%22%
1280
16th to endDay
5%13%6%12%9%45%6%5%7%23%
1536
February1st to 15thDay
9%13%7%10%8%5%8%6%45%19%
1491
16th to endDay
7%14%7%12%10%46%8%5%5%16%
1492
March1st to 15thDay
8%14%6%11%9%46%46%6%21%
1803
16th to endDay
10%12%39%6%36%6%6%8%25%
2217
April1st to 15thDay
9%8%36%5%45%5%7%7%34%
2150
16th to endDay
16%11%37%6%35%446%31%
2394
May1st to 15thDay
11%8%36%6%35%35%6%38%
2511
16th to endDay
20%6%35%6%35%5%5%7%30%
2637
June1st to 15thDay
19%6%26%6%35%5%5%8%31%
2835
16th to endDay
13%5%35%5%36%5%7%9%35%
2880
July1st to 15thDay
8%314435%5%6%8%47%
2745
16th to endDay
6%3235%245%5%8%53%
2671
August1st to 15thDay
9%425%5%35%45%8%46%
2520
16th to endDay
9%414423447%53%
2438
September1st to 15thDay
12%6%25%324447%48%
2160
16th to endDay
12%5%14424348%47%
2011
October1st to 15thDay
17%10%45%423345%37%
1800
16th to endDay
12%11%47%5%34347%34%
1609
November1st to 15thDay
9%10%6%8%6%34347%34%
1447
16th to endDay
11%12%47%8%5%6%5%5%6%27%
1359
December1st to 15thDay
9%15%7%13%11%5%6%7%5%5%12%
1260
16th to endDay
8%14%8%10%9%46%6%47%18%
1188
January1st to 15thNight
8%10%5%10%7%47%6%6%6%26%
2655
16th to endNight
6%12%7%11%7%47%5%6%6%23%
2688
February1st to 15thNight
7%12%5%11%9%46%5%45%26%
2370
16th to endNight
7%10%5%13%8%36%6%6%6%25%
1981
March1st to 15thNight
7%9%48%8%36%5%6%7%31%
2154
16th to endNight
12%11%49%7%46%45%6%26%
2007
April1st to 15thNight
9%7%35%5%35%5%6%7%40%
1798
16th to endNight
14%9%36%5%35%45%6%34%
1564
May1st to 15thNight
11%8%35%5%35%5%5%6%40%
1439
16th to endNight
17%6%25%5%35%46%6%35%
1473
June1st to 15thNight
14%6%35%42445%6%41%
1122
16th to endNight
11%5%344345%6%9%41%
1080
July1st to 15thNight
6%5%2342445%9%52%
1212
16th to endNight
5%21322346%9%58%
1494
August1st to 15thNight
7%21232435%8%56%
1440
16th to endNight
7%413313349%56%
1762
September1st to 15thNight
10%41442345%7%49%
1800
16th to endNight
10%5%14424447%51%
1947
October1st to 15thNight
13%8%25%424347%41%
2160
16th to endNight
11%10%46%5%345%5%5%37%
2272
November1st to 15thNight
13%10%37%5%25%35%7%36%
2411
16th to endNight
10%13%49%7%26%45%6%29%
2599
December1st to 15thNight
10%15%7%10%10%5%6%5%45%17%
2700
16th to endNight
7%12%6%12%10%46%6%5%8%20%
3031

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
58%7%13%17%3
1280
16th to endDay
58%7%14%14%4
1536
February1st to 15thDay
65%5%11%15%3
1491
16th to endDay
64%7%10%11%6%
1492
March1st to 15thDay
61%6%15%13%2
1803
16th to endDay
53%9%17%16%3
2217
April1st to 15thDay
45%7%17%20%7%
2150
16th to endDay
54%414%18%6%1
2394
May1st to 15thDay
44%5%11%27%10%
2511
16th to endDay
51%6%13%18%10%
2641
June1st to 15thDay
49%7%13%22%7%
2835
16th to endDay
42%8%18%23%6%
2880
July1st to 15thDay
31%6%22%29%9%
2586
16th to endDay
27%7%19%32%11%1
2503
August1st to 15thDay
34%6%22%25%8%1
2504
16th to endDay
30%5%14%35%12%2
2438
September1st to 15thDay
36%5%14%26%15%1
2160
16th to endDay
35%5%13%32%11%1
2011
October1st to 15thDay
48%414%24%8%
1800
16th to endDay
50%418%22%4
1609
November1st to 15thDay
49%5%15%20%7%
1447
16th to endDay
56%7%16%15%4
1359
December1st to 15thDay
70%6%11%9%1
1260
16th to endDay
64%415%12%1
1188
January1st to 15thNight
55%7%16%17%4
2655
16th to endNight
58%6%14%14%5%
2688
February1st to 15thNight
58%5%13%16%6%
2381
16th to endNight
56%6%14%16%6%
1981
March1st to 15thNight
49%6%17%20%5%
2154
16th to endNight
57%6%14%16%5%
2007
April1st to 15thNight
40%6%14%25%12%1
1798
16th to endNight
47%7%12%19%9%3
1564
May1st to 15thNight
42%5%11%23%16%1
1440
16th to endNight
46%6%11%19%13%1
1474
June1st to 15thNight
40%6%15%25%11%1
1122
16th to endNight
36%8%19%27%7%
1080
July1st to 15thNight
27%6%19%33%11%
1142
16th to endNight
20%7%17%36%16%2
1399
August1st to 15thNight
24%7%21%35%10%
1432
16th to endNight
25%411%34%20%3
1762
September1st to 15thNight
32%6%11%27%20%1
1800
16th to endNight
32%413%31%16%1
1947
October1st to 15thNight
41%415%27%9%
2160
16th to endNight
46%417%23%6%
2272
November1st to 15thNight
48%5%16%18%9%1
2411
16th to endNight
54%6%17%17%3
2599
December1st to 15thNight
67%6%13%11%1
2700
16th to endNight
61%6%13%14%4
3031

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
9%313%32%35%6%
65
16th to endDay
15%8%27%29%18%1
96
February1st to 15thDay
18%6%31%32%10%1
90
16th to endDay
22%427%28%13%3
81
March1st to 15thDay
12%11%41%21%9%2
93
16th to endDay
19%9%35%24%10%1
288
April1st to 15thDay
14%17%36%22%8%1
269
16th to endDay
18%10%24%28%17%1
399
May1st to 15thDay
14%7%27%31%15%2
468
16th to endDay
19%7%22%27%15%8%
517
June1st to 15thDay
17%9%27%26%15%4
495
16th to endDay
14%8%26%32%14%3
495
July1st to 15thDay
8%320%34%26%6%
475
16th to endDay
6%426%34%23%4
515
August1st to 15thDay
9%417%35%24%8%
493
16th to endDay
9%421%32%26%5%
383
September1st to 15thDay
13%11%28%27%14%4
315
16th to endDay
15%6%20%32%21%3
192
October1st to 15thDay
23%6%28%22%16%2
135
16th to endDay
22%8%28%24%15%2
99
November1st to 15thDay
13%436%25%16%3
90
16th to endDay
21%7%24%22%23%1
90
December1st to 15thDay
15%34%30%12%7%
90
16th to endDay
19%5%47%19%42
67
January1st to 15thNight
12%9%30%33%12%2
900
16th to endNight
12%11%38%28%9%
960
February1st to 15thNight
11%6%30%33%15%2
797
16th to endNight
11%425%38%16%3
632
March1st to 15thNight
10%6%34%32%14%2
720
16th to endNight
17%7%27%33%13%
663
April1st to 15thNight
11%7%33%35%11%
539
16th to endNight
19%7%26%37%7%
540
May1st to 15thNight
14%6%26%35%16%
540
16th to endNight
21%5%25%31%13%2
563
June1st to 15thNight
18%425%36%13%1
402
16th to endNight
12%6%24%39%16%
360
July1st to 15thNight
7%219%48%20%1
340
16th to endNight
6%123%43%23%1
547
August1st to 15thNight
7%219%39%27%3
539
16th to endNight
8%322%41%22%2
573
September1st to 15thNight
11%421%39%20%2
540
16th to endNight
11%326%41%14%1
561
October1st to 15thNight
18%429%29%17%1
720
16th to endNight
16%6%27%36%12%1
856
November1st to 15thNight
17%7%31%30%11%1
875
16th to endNight
16%8%32%33%7%1
900
December1st to 15thNight
17%6%30%29%14%2
900
16th to endNight
13%6%28%33%16%1
960
Page generated at 2017-10-17 14:35:27. Version ac04

Copyright 2017 A. Danko


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