North Ram
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the North Ram clear sky chart from 2005-11-06 to 2024-03-06.

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
31%
23448
14%
80429
7%
23363
39%
23363
17%
52525

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
20%
939
16%
4668
4%
926
30%
926
10%
2991
January11th to 20thNight
20%
897
22%
4525
6%
887
31%
887
12%
2641
January21st to endNight
20%
833
13%
4821
6%
814
37%
814
10%
2838
February1st to 10thNight
26%
760
12%
2660
8%
760
33%
760
13%
1807
February11th to 20thNight
25%
742
12%
2498
6%
740
34%
740
16%
1681
February21st to endNight
31%
628
18%
1884
9%
628
43%
628
21%
1270
March1st to 10thNight
30%
742
16%
2225
9%
742
39%
742
21%
1480
March11th to 20thNight
29%
720
17%
2073
7%
720
38%
720
22%
1360
March21st to endNight
32%
792
14%
2052
4%
792
37%
792
21%
1456
April1st to 10thNight
33%
720
13%
1800
4%
720
38%
720
18%
1313
April11th to 20thNight
26%
534
13%
1602
7%
534
30%
534
16%
1170
April21st to endNight
29%
503
12%
1583
7%
503
36%
503
15%
1122
May1st to 10thNight
36%
360
7%
1440
8%
360
41%
360
12%
1025
May11th to 20thNight
44%
354
10%
1240
9%
354
47%
354
23%
780
May21st to endNight
41%
388
4%
1358
1%
388
41%
388
17%
945
June1st to 10thNight
37%
360
0%
1260
0%
360
37%
360
17%
878
June11th to 20thNight
37%
360
0%
1103
0%
360
37%
360
14%
829
June21st to endNight
47%
360
0%
1080
0%
360
47%
360
25%
699
July1st to 10thNight
52%
350
0%
1080
0%
350
52%
350
26%
689
July11th to 20thNight
47%
348
3%
1218
0%
348
47%
348
22%
761
July21st to endNight
61%
394
10%
1399
9%
372
64%
372
28%
753
August1st to 10thNight
58%
358
11%
1424
15%
356
62%
356
22%
851
August11th to 20thNight
57%
400
17%
1468
19%
400
62%
400
26%
840
August21st to endNight
47%
594
19%
1782
14%
594
51%
594
26%
1125
September1st to 10thNight
42%
704
16%
1784
8%
704
46%
704
28%
1180
September11th to 20thNight
43%
720
16%
1921
9%
720
47%
720
26%
1293
September21st to endNight
35%
720
20%
1980
10%
720
43%
720
25%
1272
October1st to 10thNight
40%
720
18%
2056
10%
720
48%
720
24%
1377
October11th to 20thNight
30%
720
15%
2340
7%
720
40%
720
20%
1510
October21st to endNight
23%
792
15%
2574
6%
792
34%
792
16%
1755
November1st to 10thNight
24%
794
17%
2475
8%
794
34%
794
15%
1715
November11th to 20thNight
20%
950
17%
2850
4%
950
33%
950
17%
1876
November21st to endNight
20%
950
14%
2850
3%
950
30%
950
15%
1964
December1st to 10thNight
22%
950
18%
2850
7%
950
33%
950
18%
1949
December11th to 20thNight
24%
950
14%
3472
5%
949
33%
949
13%
2432
December21st to endNight
22%
1042
11%
5034
5%
1026
33%
1026
11%
2898

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%10%48%7%46%6%6%8%32%
78452
Night
5%8%49%7%45%6%6%8%36%
81012
TransparencyDay
47%9%14%18%9%2
78155
Night
42%9%16%20%11%2
80889
SeeingDay
20%15%29%23%10%2
14736
Night
14%14%31%27%12%1
23478

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
15%5%12%10%5%6%7%7%9%32%
2219
11th to 20thDay
27%39%8%45%8%6%9%38%
2299
21st to endDay
18%48%7%46%7%7%10%37%
2794
February1st to 10thDay
38%6%9%10%6%6%6%8%8%31%
1520
11th to 20thDay
210%6%13%8%46%6%6%8%30%
1569
21st to endDay
27%5%15%10%47%6%6%7%32%
1570
March1st to 10thDay
28%5%10%9%47%7%7%9%32%
1851
11th to 20thDay
18%6%9%8%46%7%7%11%32%
1885
21st to endDay
413%8%10%8%46%5%7%9%26%
2302
April1st to 10thDay
416%6%10%8%6%7%6%7%7%23%
2160
11th to 20thDay
8%17%6%10%7%46%5%6%8%23%
2308
21st to endDay
9%16%6%10%8%46%46%6%26%
2376
May1st to 10thDay
13%17%5%9%8%45%6%5%7%22%
2520
11th to 20thDay
12%10%37%6%5%5%5%6%9%33%
2651
21st to endDay
22%12%47%6%45%5%5%7%23%
2917
June1st to 10thDay
20%10%37%7%46%5%6%7%24%
2700
11th to 20thDay
24%10%47%6%47%5%6%8%20%
2852
21st to endDay
13%7%36%7%5%6%6%7%9%32%
2880
July1st to 10thDay
13%8%36%6%47%6%7%8%31%
2846
11th to 20thDay
14%6%26%6%36%6%7%9%35%
2700
21st to endDay
10%5%25%6%46%6%7%9%39%
2834
August1st to 10thDay
14%8%26%6%36%5%6%8%35%
2507
11th to 20thDay
12%6%25%6%35%6%7%8%40%
2430
21st to endDay
14%7%35%7%35%5%6%8%37%
2574
September1st to 10thDay
15%9%25%6%35%5%5%6%38%
2174
11th to 20thDay
14%10%25%5%3446%8%40%
2038
21st to endDay
10%9%38%6%35%45%8%39%
1980
October1st to 10thDay
9%12%47%6%45%6%47%36%
1900
11th to 20thDay
8%10%38%6%45%448%40%
1620
21st to endDay
6%11%5%9%8%45%5%6%7%34%
1782
November1st to 10thDay
411%6%11%8%45%6%7%7%32%
1580
11th to 20thDay
38%5%10%6%5%5%6%6%8%38%
1330
21st to endDay
29%49%6%5%6%5%8%11%35%
1330
December1st to 10thDay
39%5%12%9%47%6%6%6%34%
1330
11th to 20thDay
28%411%10%5%6%6%6%8%36%
1682
21st to endDay
19%48%8%46%5%6%7%43%
2442
January1st to 10thNight
17%6%15%10%5%6%6%7%8%30%
4726
11th to 20thNight
26%49%9%46%7%9%9%35%
4630
21st to endNight
18%5%10%8%5%6%6%7%10%34%
4862
February1st to 10thNight
39%410%10%5%7%5%6%8%32%
2660
11th to 20thNight
29%6%11%8%5%6%7%7%8%31%
2496
21st to endNight
6%6%12%9%5%6%7%7%7%35%
1884
March1st to 10thNight
17%5%10%8%5%6%8%8%9%33%
2225
11th to 20thNight
29%5%8%6%46%7%7%8%40%
2073
21st to endNight
312%6%10%7%45%6%6%10%33%
2052
April1st to 10thNight
410%6%9%9%46%6%6%9%30%
1800
11th to 20thNight
7%14%6%10%8%45%5%6%7%30%
1602
21st to endNight
7%15%5%7%6%35%46%7%35%
1583
May1st to 10thNight
12%15%47%6%46%5%5%7%28%
1440
11th to 20thNight
10%8%25%6%46%5%6%8%41%
1240
21st to endNight
21%9%35%335%6%7%8%32%
1358
June1st to 10thNight
20%8%36%4346%5%7%34%
1260
11th to 20thNight
20%8%37%6%36%5%6%8%27%
1103
21st to endNight
11%6%26%5%25%5%6%8%42%
1080
July1st to 10thNight
13%7%35%435%5%5%10%41%
1111
11th to 20thNight
12%6%25%6%246%7%9%40%
1260
21st to endNight
7%425%5%345%6%8%51%
1481
August1st to 10thNight
12%7%35%4345%5%10%43%
1432
11th to 20thNight
11%5%24435%46%9%47%
1468
21st to endNight
14%6%345%335%5%9%44%
1782
September1st to 10thNight
12%8%35%4245%5%8%45%
1784
11th to 20thNight
14%10%35%42345%8%41%
1921
21st to endNight
8%9%45%4245%7%7%44%
1980
October1st to 10thNight
8%10%46%6%3445%7%42%
2056
11th to 20thNight
8%8%48%7%35%5%6%8%40%
2340
21st to endNight
5%10%49%7%45%6%7%7%35%
2574
November1st to 10thNight
313%6%10%6%45%6%6%7%35%
2475
11th to 20thNight
29%5%8%7%46%6%6%10%37%
2850
21st to endNight
38%5%11%9%46%6%6%9%34%
2850
December1st to 10thNight
38%6%10%8%36%6%6%8%36%
2850
11th to 20thNight
17%5%11%11%6%6%6%8%9%31%
3510
21st to endNight
18%5%11%8%45%5%6%8%39%
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
44%7%14%20%10%5%
2219
11th to 20thDay
37%8%15%15%19%6%
2320
21st to endDay
35%11%18%27%9%1
2794
February1st to 10thDay
46%8%14%16%12%3
1520
11th to 20thDay
47%11%12%17%12%2
1577
21st to endDay
50%7%14%14%14%2
1570
March1st to 10thDay
44%10%18%18%10%2
1851
11th to 20thDay
42%9%16%21%11%1
1886
21st to endDay
52%12%15%14%6%1
2302
April1st to 10thDay
57%8%16%13%6%
2160
11th to 20thDay
59%8%12%15%5%1
2308
21st to endDay
58%8%13%14%6%1
2376
May1st to 10thDay
60%9%12%14%5%
2520
11th to 20thDay
48%9%15%17%10%
2655
21st to endDay
59%8%12%13%7%
2918
June1st to 10thDay
58%9%12%15%6%1
2700
11th to 20thDay
61%9%11%11%6%1
2852
21st to endDay
47%10%16%17%8%2
2880
July1st to 10thDay
48%9%15%19%8%1
2768
11th to 20thDay
42%12%15%20%10%1
2619
21st to endDay
39%11%15%22%12%1
2676
August1st to 10thDay
45%11%13%21%9%1
2490
11th to 20thDay
38%12%17%22%9%2
2430
21st to endDay
42%10%14%24%9%2
2574
September1st to 10thDay
45%8%14%21%11%1
2174
11th to 20thDay
42%7%15%24%11%2
2038
21st to endDay
43%8%18%17%11%2
1980
October1st to 10thDay
46%7%12%24%10%1
1900
11th to 20thDay
41%8%17%22%10%1
1620
21st to endDay
47%9%13%20%10%1
1782
November1st to 10thDay
47%9%15%17%9%2
1580
11th to 20thDay
39%10%19%20%12%1
1330
21st to endDay
38%10%20%19%9%4
1330
December1st to 10thDay
47%8%14%16%12%2
1330
11th to 20thDay
42%9%16%19%12%2
1684
21st to endDay
38%5%13%21%16%7%
2442
January1st to 10thNight
46%8%13%18%11%3
4726
11th to 20thNight
40%8%14%13%16%9%
4671
21st to endNight
40%10%20%19%10%1
4862
February1st to 10thNight
47%9%14%16%12%3
2660
11th to 20thNight
44%9%18%15%12%2
2498
21st to endNight
45%6%13%21%14%2
1884
March1st to 10thNight
40%9%18%19%12%1
2225
11th to 20thNight
39%8%16%22%14%1
2073
21st to endNight
43%10%18%19%9%1
2052
April1st to 10thNight
47%8%16%17%11%1
1800
11th to 20thNight
52%6%14%16%10%1
1602
21st to endNight
46%11%13%21%7%1
1583
May1st to 10thNight
53%8%15%18%6%
1440
11th to 20thNight
40%8%14%26%12%
1240
21st to endNight
48%8%12%23%8%1
1358
June1st to 10thNight
48%9%14%20%9%1
1260
11th to 20thNight
54%10%16%15%5%1
1103
21st to endNight
37%10%19%25%7%2
1080
July1st to 10thNight
39%8%17%25%10%1
1080
11th to 20thNight
36%11%20%23%9%1
1218
21st to endNight
29%9%17%31%13%1
1399
August1st to 10thNight
35%11%18%29%6%
1424
11th to 20thNight
31%11%21%27%10%1
1468
21st to endNight
36%8%14%28%12%1
1782
September1st to 10thNight
36%9%17%27%9%2
1784
11th to 20thNight
41%6%15%25%10%3
1921
21st to endNight
37%7%18%25%13%1
1980
October1st to 10thNight
41%8%14%25%11%1
2056
11th to 20thNight
40%8%19%21%11%1
2340
21st to endNight
44%10%14%21%10%1
2574
November1st to 10thNight
45%9%13%19%11%3
2475
11th to 20thNight
39%9%17%21%11%2
2850
21st to endNight
43%11%15%19%9%4
2850
December1st to 10thNight
44%9%13%19%13%3
2850
11th to 20thNight
45%13%15%18%8%1
3507
21st to endNight
40%7%14%21%12%6%
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
11%17%27%27%14%4
180
11th to 20thDay
14%11%35%27%9%3
180
21st to endDay
16%16%38%21%7%2
198
February1st to 10thDay
22%15%37%17%7%2
180
11th to 20thDay
13%19%35%23%10%
231
21st to endDay
14%22%30%23%8%2
382
March1st to 10thDay
15%24%35%17%7%2
441
11th to 20thDay
17%19%35%20%7%3
420
21st to endDay
22%23%28%18%8%2
462
April1st to 10thDay
25%20%27%21%6%1
420
11th to 20thDay
21%21%27%21%8%2
412
21st to endDay
24%18%26%21%10%2
420
May1st to 10thDay
27%18%24%21%9%
423
11th to 20thDay
18%10%30%26%14%2
622
21st to endDay
26%8%25%25%12%3
679
June1st to 10thDay
23%14%30%23%8%2
630
11th to 20thDay
30%12%24%22%11%1
782
21st to endDay
18%12%24%27%16%3
810
July1st to 10thDay
18%10%26%30%14%2
763
11th to 20thDay
19%10%27%25%17%1
618
21st to endDay
14%11%29%28%15%3
580
August1st to 10thDay
16%13%28%28%12%3
447
11th to 20thDay
16%16%31%25%10%2
437
21st to endDay
18%15%29%24%11%3
495
September1st to 10thDay
27%18%26%20%8%1
450
11th to 20thDay
25%14%27%25%6%3
450
21st to endDay
26%17%28%19%8%2
450
October1st to 10thDay
21%15%29%19%11%4
428
11th to 20thDay
21%15%29%23%10%2
270
21st to endDay
23%17%32%20%7%1
297
November1st to 10thDay
22%22%31%17%6%2
261
11th to 20thDay
22%18%36%16%6%1
180
21st to endDay
18%21%30%20%7%4
180
December1st to 10thDay
14%18%32%19%11%5%
180
11th to 20thDay
14%21%36%22%6%1
180
21st to endDay
12%11%34%30%11%2
198
January1st to 10thNight
13%18%39%24%6%
950
11th to 20thNight
11%17%43%21%6%1
907
21st to endNight
15%18%40%19%8%1
836
February1st to 10thNight
13%17%32%26%11%1
760
11th to 20thNight
11%15%37%29%7%1
744
21st to endNight
7%13%37%27%15%2
628
March1st to 10thNight
8%16%37%28%10%2
742
11th to 20thNight
10%15%37%28%9%1
720
21st to endNight
13%13%31%28%12%3
792
April1st to 10thNight
13%15%27%30%15%1
720
11th to 20thNight
16%15%32%27%10%
534
21st to endNight
20%14%28%27%10%1
503
May1st to 10thNight
22%9%22%32%14%1
360
11th to 20thNight
15%7%25%36%16%2
354
21st to endNight
26%420%27%23%1
389
June1st to 10thNight
25%8%23%26%16%2
360
11th to 20thNight
23%8%21%30%17%2
360
21st to endNight
16%9%17%31%23%3
360
July1st to 10thNight
17%417%37%23%1
350
11th to 20thNight
16%8%21%35%20%
348
21st to endNight
11%5%13%42%25%3
394
August1st to 10thNight
19%312%33%30%4
358
11th to 20thNight
14%417%39%25%2
400
21st to endNight
17%8%18%35%20%2
594
September1st to 10thNight
15%10%23%33%16%2
704
11th to 20thNight
22%7%20%31%18%2
720
21st to endNight
17%15%28%27%13%1
720
October1st to 10thNight
18%10%25%34%12%2
720
11th to 20thNight
15%14%33%28%8%2
720
21st to endNight
17%14%38%23%7%1
792
November1st to 10thNight
15%19%35%23%8%1
794
11th to 20thNight
13%24%38%20%41
950
21st to endNight
13%22%36%21%8%1
950
December1st to 10thNight
12%18%39%22%8%1
950
11th to 20thNight
9%20%38%25%8%1
950
21st to endNight
8%16%41%25%9%1
1045
Page generated at 2024-03-03 04:28:53. Version ac07

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