Cypress Hills Dark-Sky Preserve - SSSP
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cypress Hills Dark-Sky Preserve - SSSP clear sky chart from 2005-11-05 to 2017-08-12.

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
37%
15374
13%
46402
8%
15343
42%
15343
22%
31003

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
25%
896
11%
2685
6%
895
30%
895
15%
1983
January16th to endNight
25%
912
14%
2790
6%
912
35%
912
18%
1921
February1st to 15thNight
36%
698
10%
2288
8%
697
40%
697
18%
1597
February16th to endNight
31%
632
11%
2052
7%
632
36%
632
15%
1491
March1st to 15thNight
30%
720
12%
2047
6%
720
36%
720
22%
1435
March16th to endNight
29%
764
10%
2108
3%
764
35%
764
17%
1589
April1st to 15thNight
32%
539
12%
1743
7%
539
38%
539
19%
1175
April16th to endNight
38%
540
14%
1619
10%
540
42%
540
20%
1127
May1st to 15thNight
47%
539
13%
1440
10%
539
49%
539
29%
952
May16th to endNight
40%
446
7%
1381
5%
444
42%
444
17%
996
June1st to 15thNight
45%
360
4%
1260
3%
360
46%
360
20%
808
June16th to endNight
52%
360
6%
1260
6%
360
54%
360
28%
717
July1st to 15thNight
60%
340
8%
1190
6%
340
64%
340
37%
608
July16th to endNight
61%
400
18%
1261
17%
376
66%
376
47%
587
August1st to 15thNight
64%
527
15%
1509
13%
524
67%
524
40%
874
August16th to endNight
57%
525
23%
1575
18%
525
61%
525
38%
875
September1st to 15thNight
52%
495
19%
1647
17%
495
56%
495
30%
963
September16th to endNight
47%
645
22%
1826
15%
645
55%
645
37%
1064
October1st to 15thNight
37%
660
19%
1980
9%
660
46%
660
25%
1269
October16th to endNight
35%
741
18%
2218
9%
741
43%
741
24%
1444
November1st to 15thNight
27%
875
17%
2450
7%
875
35%
875
23%
1634
November16th to endNight
25%
900
13%
2520
6%
900
31%
900
20%
1791
December1st to 15thNight
29%
900
8%
2673
4%
900
32%
900
14%
2061
December16th to endNight
28%
960
13%
2880
5%
960
35%
960
16%
2042

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
9%7%36%6%35%5%6%7%37%
47609
Night
7%7%36%6%35%5%6%8%38%
46551
Cloud CoverDay
9%7%36%6%35%5%6%7%37%
47610
Night
7%7%37%6%35%5%6%8%38%
46553
TransparencyDay
43%8%16%21%9%1
47262
Night
42%8%16%21%10%1
46402
SeeingDay
13%8%30%29%15%3
5941
Night
10%10%33%30%12%1
15385

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
5%11%5%8%7%36%6%7%6%29%
1253
16th to endDay
27%5%8%8%6%9%7%6%7%30%
1446
February1st to 15thDay
5%8%48%9%5%6%7%5%7%31%
1575
16th to endDay
5%11%6%12%9%5%6%5%5%7%24%
1422
March1st to 15thDay
36%49%8%5%5%6%8%9%31%
1911
16th to endDay
9%10%5%10%9%35%5%6%8%25%
2114
April1st to 15thDay
9%11%46%6%45%5%7%7%30%
2203
16th to endDay
13%10%36%5%35%446%34%
2340
May1st to 15thDay
11%10%45%5%35%5%5%7%35%
2511
16th to endDay
22%8%36%5%35%5%5%8%27%
2730
June1st to 15thDay
18%7%36%6%35%5%5%7%30%
2700
16th to endDay
11%425%5%26%5%7%8%39%
2700
July1st to 15thDay
5%324425%5%6%9%49%
2700
16th to endDay
5%2134245%5%8%55%
2821
August1st to 15thDay
7%4244345%7%7%48%
2356
16th to endDay
9%31332335%6%56%
2275
September1st to 15thDay
13%5%245%23335%48%
1983
16th to endDay
13%412322448%52%
1801
October1st to 15thDay
10%9%36%5%245%6%7%38%
1650
16th to endDay
6%8%37%5%45%46%7%39%
1642
November1st to 15thDay
7%8%46%6%35%5%5%7%39%
1408
16th to endDay
7%8%48%7%46%6%6%7%32%
1440
December1st to 15thDay
6%9%6%10%10%6%8%5%6%7%22%
1284
16th to endDay
5%10%5%8%8%5%7%5%6%7%29%
1344
January1st to 15thNight
5%9%5%8%7%47%7%6%9%29%
2685
16th to endNight
38%49%8%45%6%6%8%34%
2790
February1st to 15thNight
5%7%37%8%5%7%6%6%8%32%
2277
16th to endNight
48%5%11%9%46%6%6%6%28%
2052
March1st to 15thNight
5%6%46%7%47%6%7%10%33%
2047
16th to endNight
9%9%410%7%45%6%7%8%26%
2105
April1st to 15thNight
9%8%37%6%45%5%6%7%34%
1743
16th to endNight
13%8%46%435%5%5%7%34%
1619
May1st to 15thNight
10%7%25%425%45%7%42%
1439
16th to endNight
18%7%37%5%345%6%6%32%
1381
June1st to 15thNight
14%6%245%35%446%41%
1260
16th to endNight
8%224425%5%6%8%48%
1260
July1st to 15thNight
6%22342346%8%56%
1260
16th to endNight
42321346%8%60%
1347
August1st to 15thNight
7%31442346%8%54%
1517
16th to endNight
8%41432435%7%54%
1575
September1st to 15thNight
11%6%24423436%50%
1647
16th to endNight
9%5%2343345%8%51%
1826
October1st to 15thNight
9%8%35%42445%8%42%
1980
16th to endNight
6%9%36%6%25%45%7%41%
2218
November1st to 15thNight
6%7%35%6%36%5%6%8%40%
2450
16th to endNight
6%11%47%7%45%448%34%
2520
December1st to 15thNight
310%6%9%9%6%6%6%5%7%26%
2673
16th to endNight
5%9%38%7%5%6%6%7%7%31%
2880

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
5%11%5%8%7%47%7%7%6%28%
1253
16th to endDay
28%48%9%6%9%6%6%7%29%
1446
February1st to 15thDay
5%7%48%10%47%6%5%7%30%
1575
16th to endDay
6%11%7%11%9%5%6%45%6%24%
1422
March1st to 15thDay
36%39%9%5%6%6%9%8%30%
1911
16th to endDay
9%10%5%10%9%35%6%6%8%24%
2115
April1st to 15thDay
9%10%46%6%45%5%7%7%30%
2203
16th to endDay
13%11%36%5%25%45%6%34%
2340
May1st to 15thDay
11%11%36%5%345%47%35%
2511
16th to endDay
21%9%36%5%35%5%5%7%27%
2730
June1st to 15thDay
17%8%35%6%35%5%5%7%30%
2700
16th to endDay
10%5%25%5%35%7%6%9%38%
2700
July1st to 15thDay
5%324425%47%10%49%
2700
16th to endDay
5%213425%5%6%8%55%
2821
August1st to 15thDay
7%424425%5%6%8%47%
2356
16th to endDay
8%41332335%7%55%
2275
September1st to 15thDay
13%6%24423436%47%
1983
16th to endDay
12%413322448%51%
1801
October1st to 15thDay
9%9%37%5%245%6%7%38%
1650
16th to endDay
6%9%37%5%45%45%8%38%
1642
November1st to 15thDay
7%8%46%5%35%5%6%7%38%
1408
16th to endDay
7%8%48%7%46%5%7%7%31%
1440
December1st to 15thDay
6%10%6%11%10%5%8%5%6%6%22%
1284
16th to endDay
6%11%5%9%9%46%5%6%7%27%
1344
January1st to 15thNight
49%5%8%7%47%6%7%9%28%
2685
16th to endNight
38%49%9%46%5%6%9%33%
2790
February1st to 15thNight
5%7%38%6%49%6%7%8%32%
2277
16th to endNight
48%5%11%8%47%5%6%7%28%
2052
March1st to 15thNight
5%6%38%7%46%6%6%10%33%
2047
16th to endNight
9%9%49%8%447%6%8%26%
2108
April1st to 15thNight
9%7%47%7%35%47%8%34%
1743
16th to endNight
12%9%46%5%35%5%5%6%35%
1619
May1st to 15thNight
10%7%25%435%45%7%42%
1439
16th to endNight
18%7%46%6%35%45%6%32%
1380
June1st to 15thNight
14%6%25%43445%6%41%
1260
16th to endNight
8%315%4246%6%8%47%
1260
July1st to 15thNight
5%31332436%8%56%
1260
16th to endNight
411222446%8%61%
1347
August1st to 15thNight
7%32342335%10%53%
1517
16th to endNight
7%4145%2235%7%54%
1575
September1st to 15thNight
11%5%34424445%50%
1647
16th to endNight
8%5%2442345%7%51%
1826
October1st to 15thNight
9%7%36%4235%6%8%42%
1980
16th to endNight
6%9%36%6%3445%8%40%
2218
November1st to 15thNight
7%6%36%6%36%5%6%8%39%
2450
16th to endNight
6%11%48%7%445%5%7%35%
2520
December1st to 15thNight
311%5%9%10%5%7%6%6%7%25%
2673
16th to endNight
5%9%48%7%5%5%7%7%8%30%
2880

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
50%11%13%18%4
1253
16th to endDay
49%10%17%15%41
1446
February1st to 15thDay
50%9%16%17%5%
1575
16th to endDay
58%9%12%12%6%
1422
March1st to 15thDay
44%12%20%17%4
1911
16th to endDay
54%10%16%15%3
2115
April1st to 15thDay
49%8%16%19%6%
2203
16th to endDay
48%8%15%20%5%1
2340
May1st to 15thDay
46%7%15%22%7%
2511
16th to endDay
55%7%14%16%6%
2734
June1st to 15thDay
51%7%15%16%7%
2700
16th to endDay
38%8%19%25%7%
2700
July1st to 15thDay
28%8%19%27%14%2
2541
16th to endDay
24%7%14%29%20%3
2644
August1st to 15thDay
30%10%18%25%13%2
2340
16th to endDay
27%414%30%20%3
2275
September1st to 15thDay
37%5%13%23%15%3
1983
16th to endDay
30%6%13%30%16%1
1801
October1st to 15thDay
42%7%17%23%8%
1650
16th to endDay
41%7%18%23%8%
1642
November1st to 15thDay
41%9%19%21%6%
1408
16th to endDay
48%10%17%15%8%
1440
December1st to 15thDay
58%8%16%15%1
1284
16th to endDay
52%9%17%16%4
1344
January1st to 15thNight
48%11%17%16%31
2685
16th to endNight
44%8%18%18%7%1
2790
February1st to 15thNight
47%8%17%17%7%1
2288
16th to endNight
52%7%12%17%7%1
2052
March1st to 15thNight
42%11%20%18%7%
2047
16th to endNight
52%7%14%17%6%
2108
April1st to 15thNight
45%7%16%21%8%
1743
16th to endNight
47%7%12%19%9%2
1619
May1st to 15thNight
39%6%12%28%12%1
1440
16th to endNight
51%7%14%16%10%
1381
June1st to 15thNight
41%8%16%22%9%
1260
16th to endNight
31%8%17%29%12%
1260
July1st to 15thNight
24%6%13%33%18%3
1190
16th to endNight
17%6%15%30%25%4
1261
August1st to 15thNight
27%6%17%30%14%3
1509
16th to endNight
28%411%25%24%5%
1575
September1st to 15thNight
35%412%23%17%6%
1647
16th to endNight
30%5%15%27%18%3
1826
October1st to 15thNight
38%7%18%23%11%
1980
16th to endNight
39%7%16%23%11%
2218
November1st to 15thNight
39%9%18%21%10%1
2450
16th to endNight
46%8%21%14%8%
2520
December1st to 15thNight
53%11%16%13%4
2673
16th to endNight
47%9%17%20%4
2880

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
10%10%26%15%26%11%
60
16th to endDay
5%9%40%22%16%4
71
February1st to 15thDay
12%17%36%24%5%3
90
16th to endDay
17%6%32%35%7%1
81
March1st to 15thDay
7%16%47%22%6%
231
16th to endDay
12%13%44%23%5%
288
April1st to 15thDay
12%20%35%24%7%
269
16th to endDay
20%9%31%25%10%1
270
May1st to 15thDay
13%8%27%31%14%3
468
16th to endDay
23%8%25%21%15%5%
517
June1st to 15thDay
15%8%30%26%16%2
495
16th to endDay
12%9%28%27%20%3
495
July1st to 15thDay
8%322%41%21%2
475
16th to endDay
7%5%28%34%20%4
515
August1st to 15thDay
8%424%36%20%5%
366
16th to endDay
11%6%25%33%21%1
268
September1st to 15thDay
20%5%27%30%13%2
255
16th to endDay
12%10%25%32%15%3
233
October1st to 15thDay
30%6%35%20%6%1
90
16th to endDay
11%12%26%34%14%1
96
November1st to 15thDay
7%11%41%30%10%
90
16th to endDay
7%15%41%13%16%5%
90
December1st to 15thDay
10%10%35%29%6%6%
64
16th to endDay
12%12%35%28%6%4
64
January1st to 15thNight
9%17%39%22%9%1
900
16th to endNight
7%18%37%25%8%1
912
February1st to 15thNight
8%13%32%30%11%2
704
16th to endNight
6%10%37%30%12%2
632
March1st to 15thNight
7%10%43%26%9%1
720
16th to endNight
13%9%36%29%9%1
764
April1st to 15thNight
12%8%38%28%10%1
539
16th to endNight
17%7%28%31%14%
540
May1st to 15thNight
14%7%25%33%17%1
540
16th to endNight
18%8%23%30%18%2
446
June1st to 15thNight
16%6%26%33%16%1
360
16th to endNight
8%7%26%38%16%1
360
July1st to 15thNight
8%322%47%15%1
340
16th to endNight
5%326%40%22%1
400
August1st to 15thNight
8%318%40%26%1
527
16th to endNight
10%421%40%22%
525
September1st to 15thNight
15%422%34%20%2
495
16th to endNight
9%6%33%33%14%3
645
October1st to 15thNight
14%8%31%30%13%1
660
16th to endNight
11%12%33%33%9%
741
November1st to 15thNight
11%14%42%24%6%1
875
16th to endNight
10%12%44%27%5%
900
December1st to 15thNight
8%13%37%29%9%1
900
16th to endNight
10%12%39%27%9%1
960
Page generated at 2017-08-13 12:16:44. Version ac04

Copyright 2017 A. Danko


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