This page made possible by the sponsorship of:
.

Northern Prairie Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Northern Prairie Star Party clear sky chart from 2005-11-06 to 2024-01-16.

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
41%
23523
11%
74683
7%
23494
45%
23494
19%
51485

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
34%
946
8%
2836
4%
946
37%
946
14%
2155
January11th to 20thNight
33%
926
15%
2776
8%
926
40%
926
18%
1992
January21st to endNight
27%
928
12%
2908
6%
928
35%
928
13%
2192
February1st to 10thNight
37%
720
11%
2520
8%
720
43%
720
14%
1814
February11th to 20thNight
37%
700
12%
2281
10%
700
41%
700
17%
1630
February21st to endNight
44%
592
16%
1906
13%
592
50%
592
20%
1315
March1st to 10thNight
42%
720
13%
2151
11%
720
45%
720
17%
1587
March11th to 20thNight
39%
720
15%
1980
8%
720
44%
720
21%
1443
March21st to endNight
40%
792
10%
2178
5%
792
43%
792
20%
1622
April1st to 10thNight
47%
604
14%
1694
7%
604
51%
604
24%
1157
April11th to 20thNight
39%
533
13%
1601
9%
533
43%
533
18%
1163
April21st to endNight
44%
540
11%
1620
11%
540
46%
540
22%
1113
May1st to 10thNight
45%
437
10%
1350
7%
437
48%
437
19%
949
May11th to 20thNight
52%
354
7%
1239
7%
354
53%
354
21%
796
May21st to endNight
42%
388
1%
1358
0%
388
43%
388
17%
949
June1st to 10thNight
44%
360
0%
1260
0%
360
44%
360
16%
879
June11th to 20thNight
40%
360
0%
1260
0%
360
40%
360
12%
967
June21st to endNight
59%
360
0%
1260
0%
360
59%
360
22%
809
July1st to 10thNight
55%
350
0%
1225
0%
350
55%
350
24%
770
July11th to 20thNight
55%
348
0%
1218
0%
348
55%
348
21%
789
July21st to endNight
60%
394
6%
1302
5%
372
62%
372
30%
728
August1st to 10thNight
58%
358
7%
1324
9%
356
61%
356
22%
810
August11th to 20thNight
58%
500
10%
1568
11%
500
60%
500
29%
979
August21st to endNight
54%
594
17%
1782
13%
594
57%
594
28%
1144
September1st to 10thNight
54%
541
15%
1661
11%
541
57%
541
29%
1028
September11th to 20thNight
53%
720
18%
1980
11%
720
56%
720
32%
1247
September21st to endNight
48%
720
20%
1980
13%
720
54%
720
31%
1265
October1st to 10thNight
44%
720
16%
2114
11%
720
49%
720
25%
1408
October11th to 20thNight
40%
720
18%
2268
11%
720
48%
720
23%
1461
October21st to endNight
34%
823
15%
2605
8%
823
42%
823
19%
1801
November1st to 10thNight
32%
925
14%
2590
9%
925
36%
925
16%
1947
November11th to 20thNight
31%
950
12%
2759
6%
950
37%
950
15%
2074
November21st to endNight
31%
950
10%
2850
5%
950
35%
950
17%
2092
December1st to 10thNight
32%
950
12%
2850
7%
950
36%
950
16%
2136
December11th to 20thNight
32%
949
11%
3478
6%
949
37%
949
12%
2597
December21st to endNight
35%
1031
8%
4951
5%
1026
41%
1026
13%
2677

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
10%9%48%7%46%5%6%8%34%
74664
Night
8%9%48%7%46%6%6%8%34%
75139
TransparencyDay
46%9%17%21%7%1
74345
Night
46%8%15%20%9%1
74976
SeeingDay
13%7%25%31%19%6%
14338
Night
12%6%28%36%16%2
23547

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
6%10%6%11%9%7%8%5%5%7%27%
1329
11th to 20thDay
7%10%5%10%8%45%5%7%7%30%
1295
21st to endDay
6%11%6%13%10%6%6%47%7%23%
1462
February1st to 10thDay
8%12%6%11%9%46%5%7%7%26%
1440
11th to 20thDay
7%12%6%11%6%5%6%7%7%8%25%
1565
21st to endDay
5%11%6%8%10%5%7%6%6%9%26%
1349
March1st to 10thDay
7%13%6%10%10%5%6%6%6%8%23%
1809
11th to 20thDay
8%12%5%8%7%45%5%5%8%33%
1979
21st to endDay
10%12%6%12%8%45%5%6%8%24%
2178
April1st to 10thDay
9%10%6%7%7%5%7%6%6%7%30%
2263
11th to 20thDay
13%12%48%6%35%5%6%7%30%
2310
21st to endDay
14%10%36%6%45%45%8%34%
2340
May1st to 10thDay
12%9%48%7%46%6%6%8%29%
2606
11th to 20thDay
9%6%36%6%46%6%6%8%40%
2654
21st to endDay
17%6%37%5%45%5%6%7%34%
2917
June1st to 10thDay
14%8%37%6%37%6%6%7%30%
2700
11th to 20thDay
20%9%37%7%5%6%5%6%7%24%
2700
21st to endDay
11%6%26%6%46%7%7%10%35%
2700
July1st to 10thDay
10%437%6%45%6%6%9%40%
2700
11th to 20thDay
10%5%25%5%46%7%9%9%38%
2700
21st to endDay
9%5%345%35%6%6%9%45%
2938
August1st to 10thDay
10%5%26%5%35%5%7%10%41%
2607
11th to 20thDay
10%5%25%6%345%6%9%46%
2333
21st to endDay
10%6%25%5%346%7%10%43%
2574
September1st to 10thDay
11%6%35%6%35%5%6%8%42%
2296
11th to 20thDay
14%8%36%43445%7%42%
1980
21st to endDay
9%7%35%5%345%5%9%45%
1980
October1st to 10thDay
11%11%37%7%35%45%7%37%
1846
11th to 20thDay
10%7%47%5%35%5%6%9%39%
1690
21st to endDay
8%12%5%6%7%46%6%7%9%31%
1733
November1st to 10thDay
9%14%6%9%7%46%6%6%7%26%
1488
11th to 20thDay
6%9%8%13%8%45%5%47%30%
1419
21st to endDay
6%9%6%12%7%45%5%6%8%32%
1330
December1st to 10thDay
5%12%5%11%10%5%7%6%7%7%24%
1330
11th to 20thDay
7%9%412%9%47%6%7%11%25%
1682
21st to endDay
48%37%7%46%5%5%7%43%
2442
January1st to 10thNight
6%10%5%10%11%6%7%7%6%7%25%
2836
11th to 20thNight
411%5%10%9%46%5%6%9%30%
2776
21st to endNight
7%12%6%11%9%47%5%6%8%26%
2908
February1st to 10thNight
6%9%5%11%11%5%7%7%5%7%28%
2520
11th to 20thNight
7%11%5%9%7%5%7%5%7%7%29%
2281
21st to endNight
49%49%9%5%6%6%6%10%31%
1906
March1st to 10thNight
7%10%5%10%9%47%5%5%9%28%
2151
11th to 20thNight
7%10%5%8%9%47%6%7%7%30%
1980
21st to endNight
10%12%5%8%7%35%5%8%9%28%
2178
April1st to 10thNight
6%9%47%7%46%6%7%9%35%
1694
11th to 20thNight
11%11%5%8%6%5%6%5%6%7%29%
1601
21st to endNight
13%9%37%5%35%6%6%7%35%
1620
May1st to 10thNight
14%8%38%7%46%6%6%7%32%
1350
11th to 20thNight
9%8%37%7%46%5%6%7%38%
1239
21st to endNight
18%7%26%8%445%6%6%33%
1358
June1st to 10thNight
16%7%46%7%46%6%6%8%31%
1260
11th to 20thNight
17%8%38%7%5%6%6%7%8%24%
1260
21st to endNight
9%435%6%5%6%7%7%11%37%
1260
July1st to 10thNight
10%6%36%6%45%5%8%10%38%
1260
11th to 20thNight
10%436%5%35%7%8%11%38%
1260
21st to endNight
9%425%5%25%47%10%47%
1379
August1st to 10thNight
10%426%6%46%6%8%10%39%
1331
11th to 20thNight
12%5%346%345%6%9%43%
1568
21st to endNight
9%5%26%5%45%6%6%8%42%
1782
September1st to 10thNight
11%5%25%5%345%7%9%44%
1661
11th to 20thNight
13%6%244345%5%6%49%
1980
21st to endNight
8%6%25%5%35%5%5%7%47%
1980
October1st to 10thNight
12%8%46%5%345%6%7%40%
2114
11th to 20thNight
10%9%36%6%36%46%8%39%
2268
21st to endNight
8%11%48%8%46%6%5%8%33%
2605
November1st to 10thNight
12%14%6%7%7%45%5%6%6%29%
2590
11th to 20thNight
7%11%5%9%9%46%6%5%7%29%
2759
21st to endNight
5%10%5%11%10%46%5%5%8%30%
2850
December1st to 10thNight
7%11%5%11%9%5%6%5%6%7%27%
2850
11th to 20thNight
6%11%5%13%9%46%7%7%8%25%
3510
21st to endNight
37%37%7%46%5%6%8%44%
5214

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
57%7%10%18%7%1
1329
11th to 20thDay
50%9%14%16%9%2
1295
21st to endDay
59%7%11%15%7%
1462
February1st to 10thDay
57%5%15%16%7%
1440
11th to 20thDay
54%7%17%14%7%
1574
21st to endDay
52%7%13%20%7%
1349
March1st to 10thDay
57%8%16%15%4
1809
11th to 20thDay
48%7%14%21%11%
1980
21st to endDay
58%9%13%16%4
2178
April1st to 10thDay
50%9%14%17%8%1
2263
11th to 20thDay
50%7%15%20%8%
2310
21st to endDay
48%7%15%21%7%2
2340
May1st to 10thDay
49%8%15%19%8%
2606
11th to 20thDay
39%8%13%27%11%1
2658
21st to endDay
47%8%14%21%11%
2918
June1st to 10thDay
49%9%14%20%8%
2700
11th to 20thDay
57%8%15%15%41
2700
21st to endDay
40%13%21%20%5%1
2700
July1st to 10thDay
37%11%22%25%41
2626
11th to 20thDay
38%12%25%23%2
2619
21st to endDay
33%11%26%26%3
2775
August1st to 10thDay
37%11%25%24%3
2589
11th to 20thDay
33%10%25%25%7%
2333
21st to endDay
33%11%21%27%7%1
2574
September1st to 10thDay
38%9%20%24%7%2
2296
11th to 20thDay
40%8%18%28%7%
1980
21st to endDay
35%10%19%27%8%2
1980
October1st to 10thDay
46%7%16%22%9%
1846
11th to 20thDay
42%9%17%23%10%
1690
21st to endDay
48%10%13%22%7%1
1733
November1st to 10thDay
55%8%15%15%6%1
1488
11th to 20thDay
53%7%16%19%4
1419
21st to endDay
50%9%18%18%6%1
1330
December1st to 10thDay
56%8%13%14%8%1
1330
11th to 20thDay
49%10%18%17%6%
1684
21st to endDay
40%5%10%29%14%2
2442
January1st to 10thNight
56%8%14%13%7%1
2836
11th to 20thNight
50%7%17%17%7%1
2776
21st to endNight
56%7%13%16%7%1
2908
February1st to 10thNight
54%6%14%17%8%1
2520
11th to 20thNight
51%8%15%17%10%
2282
21st to endNight
47%8%12%22%9%1
1906
March1st to 10thNight
53%7%14%19%7%
2151
11th to 20thNight
49%8%12%20%10%1
1980
21st to endNight
49%9%16%17%7%1
2178
April1st to 10thNight
43%8%16%20%13%1
1694
11th to 20thNight
51%7%12%18%8%3
1601
21st to endNight
44%8%14%21%11%2
1620
May1st to 10thNight
47%9%11%23%8%2
1350
11th to 20thNight
43%7%13%23%13%1
1239
21st to endNight
50%8%11%20%10%2
1358
June1st to 10thNight
48%10%13%22%7%1
1260
11th to 20thNight
55%12%12%14%6%
1260
21st to endNight
37%13%22%23%5%1
1260
July1st to 10thNight
37%10%20%25%6%1
1225
11th to 20thNight
37%14%22%21%6%
1218
21st to endNight
29%10%25%31%5%
1302
August1st to 10thNight
36%12%24%24%4
1324
11th to 20thNight
36%8%24%25%7%
1568
21st to endNight
37%9%15%29%9%
1782
September1st to 10thNight
34%9%21%23%10%3
1661
11th to 20thNight
35%7%18%29%10%2
1980
21st to endNight
34%9%15%27%13%3
1980
October1st to 10thNight
43%7%15%24%11%1
2114
11th to 20thNight
41%7%16%26%9%1
2268
21st to endNight
47%8%15%22%7%1
2605
November1st to 10thNight
55%7%12%19%7%1
2590
11th to 20thNight
54%8%14%17%6%1
2759
21st to endNight
52%8%16%18%6%1
2850
December1st to 10thNight
55%7%13%16%8%1
2850
11th to 20thNight
55%9%16%13%7%
3507
21st to endNight
37%7%16%20%17%3
5214

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
9%5%27%37%17%4
180
11th to 20thDay
11%10%21%36%19%3
170
21st to endDay
8%8%34%31%15%5%
176
February1st to 10thDay
9%9%31%37%12%2
160
11th to 20thDay
11%8%31%33%14%3
236
21st to endDay
8%7%27%31%19%8%
215
March1st to 10thDay
10%8%29%33%18%2
420
11th to 20thDay
9%5%33%32%15%6%
420
21st to endDay
13%428%30%20%4
462
April1st to 10thDay
9%11%29%34%12%5%
420
11th to 20thDay
17%7%20%33%18%4
412
21st to endDay
18%10%25%30%14%3
420
May1st to 10thDay
14%9%21%33%17%6%
589
11th to 20thDay
9%6%24%34%20%7%
625
21st to endDay
17%6%22%27%20%8%
679
June1st to 10thDay
16%9%25%33%15%3
630
11th to 20thDay
20%7%25%23%17%7%
630
21st to endDay
11%5%21%30%23%10%
630
July1st to 10thDay
11%316%35%26%9%
621
11th to 20thDay
12%419%32%25%8%
618
21st to endDay
9%5%19%32%26%10%
684
August1st to 10thDay
12%5%17%31%23%13%
547
11th to 20thDay
9%5%23%31%24%7%
437
21st to endDay
11%7%18%30%25%9%
495
September1st to 10thDay
13%9%27%30%16%5%
450
11th to 20thDay
18%6%26%31%16%3
450
21st to endDay
14%12%26%28%15%4
450
October1st to 10thDay
17%9%25%28%17%4
316
11th to 20thDay
12%9%32%30%16%2
270
21st to endDay
13%11%36%24%13%3
297
November1st to 10thDay
20%6%30%30%11%3
270
11th to 20thDay
11%10%35%33%9%1
221
21st to endDay
7%9%36%33%11%4
180
December1st to 10thDay
8%10%31%31%15%6%
180
11th to 20thDay
8%8%31%35%17%1
180
21st to endDay
8%6%24%41%17%5%
198
January1st to 10thNight
11%7%32%36%13%2
950
11th to 20thNight
9%8%33%36%12%2
926
21st to endNight
13%9%33%33%10%2
928
February1st to 10thNight
8%9%27%36%19%2
720
11th to 20thNight
10%7%33%35%15%1
704
21st to endNight
7%425%38%21%5%
592
March1st to 10thNight
10%427%41%16%2
720
11th to 20thNight
11%431%36%15%3
720
21st to endNight
13%5%26%36%17%3
792
April1st to 10thNight
8%8%27%34%20%3
604
11th to 20thNight
14%5%30%37%13%2
533
21st to endNight
16%6%24%39%15%1
540
May1st to 10thNight
15%7%22%36%19%2
437
11th to 20thNight
12%5%21%40%21%2
354
21st to endNight
19%5%22%33%19%2
389
June1st to 10thNight
16%7%21%38%15%2
360
11th to 20thNight
19%6%23%32%19%2
360
21st to endNight
11%418%38%24%5%
360
July1st to 10thNight
12%317%42%27%1
350
11th to 20thNight
11%318%47%18%1
348
21st to endNight
9%418%39%27%3
394
August1st to 10thNight
12%218%35%29%5%
358
11th to 20thNight
13%5%16%37%27%2
500
21st to endNight
11%323%37%26%1
594
September1st to 10thNight
13%321%38%23%2
541
11th to 20thNight
15%421%40%18%1
720
21st to endNight
11%5%30%39%15%1
720
October1st to 10thNight
16%427%37%16%1
720
11th to 20thNight
13%431%36%15%1
720
21st to endNight
14%6%35%34%11%
823
November1st to 10thNight
19%7%31%33%8%2
925
11th to 20thNight
14%7%35%30%11%3
950
21st to endNight
9%5%39%34%11%1
950
December1st to 10thNight
13%8%33%29%14%3
950
11th to 20thNight
11%7%34%35%12%1
950
21st to endNight
9%431%38%15%3
1045
Page generated at 2024-01-12 23:38:14. Version ac07

Copyright 2024 Attilla Danko


Northern Prairie Star Party Clear Sky Chart |Charts Home