Anoka-Ramsey Community College (Cambridge)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Anoka-Ramsey Community College (Cambridge) clear sky chart from 2005-11-05 to 2017-09-10.

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
39%
16130
16%
46566
9%
16083
44%
16083
24%
31456

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
32%
900
14%
2506
7%
895
37%
895
21%
1795
January16th to endNight
25%
960
12%
2562
5%
960
30%
960
17%
1946
February1st to 15thNight
32%
879
14%
2288
4%
875
38%
875
24%
1600
February16th to endNight
31%
757
13%
2019
5%
757
37%
757
22%
1438
March1st to 15thNight
33%
586
14%
2026
10%
586
39%
586
19%
1351
March16th to endNight
34%
576
16%
2094
13%
576
43%
576
17%
1410
April1st to 15thNight
33%
539
16%
1797
13%
539
41%
539
21%
1182
April16th to endNight
32%
540
16%
1662
10%
540
40%
540
18%
1198
May1st to 15thNight
33%
540
14%
1482
6%
540
39%
540
24%
1043
May16th to endNight
45%
563
14%
1498
6%
561
49%
561
29%
994
June1st to 15thNight
49%
540
12%
1440
4%
540
52%
540
32%
923
June16th to endNight
58%
540
16%
1272
7%
540
60%
540
41%
807
July1st to 15thNight
63%
510
15%
1284
6%
510
65%
510
43%
789
July16th to endNight
66%
564
20%
1417
10%
531
68%
531
44%
814
August1st to 15thNight
67%
539
21%
1608
19%
536
70%
536
37%
916
August16th to endNight
58%
573
22%
1786
21%
573
63%
573
35%
1034
September1st to 15thNight
59%
525
22%
1750
20%
525
67%
525
36%
943
September16th to endNight
46%
536
19%
1817
13%
536
54%
536
29%
1057
October1st to 15thNight
42%
660
24%
1980
15%
660
48%
660
31%
1189
October16th to endNight
34%
704
15%
2135
9%
704
39%
704
20%
1463
November1st to 15thNight
34%
839
19%
2415
10%
839
41%
839
23%
1627
November16th to endNight
31%
900
15%
2520
9%
900
36%
900
18%
1847
December1st to 15thNight
26%
900
9%
2520
4%
900
31%
900
16%
1933
December16th to endNight
22%
960
10%
2688
3%
960
29%
960
12%
2157

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
14%7%36%5%3445%7%36%
48059
Night
13%8%36%5%24446%40%
46732
Cloud CoverDay
26%6%25%5%23446%32%
48070
Night
25%7%25%423345%35%
46736
Cloud CoverDay
13%8%36%5%3445%7%36%
48068
Night
13%8%36%5%2445%6%39%
46736
TransparencyDay
46%6%13%23%9%
47744
Night
44%5%13%23%10%1
46566
SeeingDay
16%6%27%28%15%4
6126
Night
16%6%29%32%12%1
16131

By Month

Percentage Cloud Cover NE (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
10%9%6%8%7%36%45%7%28%
1432
16th to endDay
10%13%6%10%6%346%6%7%24%
1659
February1st to 15thDay
8%11%6%9%7%35%347%32%
1575
16th to endDay
10%11%5%8%7%35%5%47%31%
1452
March1st to 15thDay
14%8%47%5%35%35%7%33%
1933
16th to endDay
19%9%36%32445%6%32%
2130
April1st to 15thDay
17%9%25%5%34345%37%
2151
16th to endDay
23%10%36%5%34346%29%
2295
May1st to 15thDay
20%8%36%6%45%445%30%
2469
16th to endDay
14%6%25%6%3445%8%36%
2617
June1st to 15thDay
16%6%25%42445%8%39%
2520
16th to endDay
10%425%5%35%5%7%9%40%
2682
July1st to 15thDay
6%4244245%6%8%51%
2595
16th to endDay
7%3144345%6%10%48%
2655
August1st to 15thDay
8%425%5%25%6%7%9%42%
2340
16th to endDay
14%5%23323448%46%
2415
September1st to 15thDay
8%425%5%345%6%8%46%
2097
16th to endDay
15%425%434447%41%
1801
October1st to 15thDay
16%7%245%23446%41%
1650
16th to endDay
21%9%35%5%2334435%
1735
November1st to 15thDay
14%10%37%5%2445%5%35%
1440
16th to endDay
16%12%36%5%345%6%6%28%
1440
December1st to 15thDay
16%12%7%7%8%3445%5%23%
1440
16th to endDay
17%15%9%11%5%35%33420%
1536
January1st to 15thNight
11%8%5%8%5%3445%7%34%
2506
16th to endNight
12%13%6%10%5%24446%29%
2562
February1st to 15thNight
7%11%48%5%3445%6%38%
2285
16th to endNight
9%9%47%6%46%446%36%
2019
March1st to 15thNight
12%9%36%6%34436%39%
2014
16th to endNight
17%8%45%6%13446%36%
2094
April1st to 15thNight
18%9%36%413335%39%
1797
16th to endNight
24%7%4441445%5%33%
1662
May1st to 15thNight
19%6%25%423446%39%
1482
16th to endNight
12%425%5%26%5%5%7%42%
1496
June1st to 15thNight
12%4245%2346%8%45%
1440
16th to endNight
9%315%32345%9%51%
1272
July1st to 15thNight
5%1144245%5%8%54%
1362
16th to endNight
5%2134245%6%9%55%
1513
August1st to 15thNight
9%315%42335%8%53%
1617
16th to endNight
10%424413346%53%
1786
September1st to 15thNight
8%32442345%6%54%
1750
16th to endNight
13%324323447%49%
1817
October1st to 15thNight
13%6%23323347%48%
1980
16th to endNight
20%8%35%423345%38%
2135
November1st to 15thNight
14%9%36%424446%40%
2415
16th to endNight
15%8%5%6%6%3435%6%32%
2520
December1st to 15thNight
13%13%5%9%6%34435%29%
2520
16th to endNight
16%16%5%10%7%24345%22%
2688

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
23%7%47%6%35%45%6%25%
1432
16th to endDay
24%12%48%6%335%5%6%19%
1659
February1st to 15thDay
23%10%47%6%24236%28%
1575
16th to endDay
23%9%37%7%34435%27%
1452
March1st to 15thDay
26%7%26%434345%29%
1944
16th to endDay
31%8%26%323345%27%
2130
April1st to 15thDay
30%7%245%2333431%
2151
16th to endDay
36%9%25%42333423%
2295
May1st to 15thDay
32%7%26%6%3433425%
2469
16th to endDay
29%5%245%24345%30%
2617
June1st to 15thDay
30%5%2442345%6%31%
2520
16th to endDay
25%31443445%8%33%
2682
July1st to 15thDay
22%41332335%6%42%
2595
16th to endDay
23%21342345%8%38%
2655
August1st to 15thDay
16%414435%6%7%8%38%
2340
16th to endDay
20%414323447%43%
2415
September1st to 15thDay
16%3144235%5%7%43%
2097
16th to endDay
21%424433446%40%
1801
October1st to 15thDay
24%6%25%5%22346%38%
1650
16th to endDay
26%7%25%42333434%
1735
November1st to 15thDay
25%9%26%42344333%
1440
16th to endDay
29%11%25%5%23435%25%
1440
December1st to 15thDay
29%10%5%6%7%2333420%
1440
16th to endDay
29%13%7%10%44321317%
1536
January1st to 15thNight
23%7%37%5%23346%30%
2506
16th to endNight
26%12%5%9%423345%24%
2562
February1st to 15thNight
23%10%36%423345%32%
2278
16th to endNight
21%8%26%6%35%435%31%
2019
March1st to 15thNight
25%8%25%5%23335%34%
2026
16th to endNight
31%7%3442233433%
2094
April1st to 15thNight
31%7%25%31333433%
1797
16th to endNight
37%7%3431334426%
1662
May1st to 15thNight
31%6%25%322435%33%
1481
16th to endNight
27%41442445%5%34%
1496
June1st to 15thNight
26%315%322346%38%
1440
16th to endNight
23%314322347%43%
1272
July1st to 15thNight
21%21332345%6%45%
1362
16th to endNight
21%212323447%46%
1513
August1st to 15thNight
16%21442235%7%49%
1617
16th to endNight
17%314412246%50%
1786
September1st to 15thNight
15%314323446%50%
1750
16th to endNight
20%313313346%48%
1817
October1st to 15thNight
21%6%13323246%44%
1980
16th to endNight
27%7%25%323235%35%
2135
November1st to 15thNight
25%7%25%41333437%
2415
16th to endNight
28%7%45%5%3434427%
2520
December1st to 15thNight
27%12%48%5%2333424%
2520
16th to endNight
28%14%49%6%2323419%
2688

Percentage Cloud Cover SE (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
10%10%6%8%7%36%46%6%28%
1432
16th to endDay
10%13%6%11%6%35%6%6%6%23%
1659
February1st to 15thDay
8%10%6%9%7%35%347%33%
1575
16th to endDay
10%11%48%7%35%446%31%
1452
March1st to 15thDay
13%9%46%6%34446%33%
1944
16th to endDay
18%10%36%424446%31%
2128
April1st to 15thDay
16%9%36%5%24345%37%
2151
16th to endDay
23%9%36%5%34445%29%
2295
May1st to 15thDay
19%8%37%6%445%45%30%
2469
16th to endDay
14%7%35%6%3445%7%35%
2617
June1st to 15thDay
15%6%25%5%3446%8%38%
2520
16th to endDay
10%4246%45%5%7%9%39%
2682
July1st to 15thDay
6%4245%2446%9%50%
2595
16th to endDay
6%4144345%6%10%47%
2655
August1st to 15thDay
8%3246%35%6%7%9%41%
2340
16th to endDay
13%42432345%7%46%
2415
September1st to 15thDay
8%4245%3447%7%46%
2097
16th to endDay
14%6%245%335%47%40%
1801
October1st to 15thDay
16%8%25%423446%41%
1650
16th to endDay
21%8%35%5%23435%35%
1735
November1st to 15thDay
14%10%47%5%2445%5%35%
1440
16th to endDay
16%12%26%6%25%5%6%6%28%
1440
December1st to 15thDay
16%11%7%7%8%3445%6%22%
1440
16th to endDay
17%15%8%11%5%5%342420%
1536
January1st to 15thNight
11%9%49%5%35%45%7%33%
2506
16th to endNight
11%14%5%10%5%24446%28%
2562
February1st to 15thNight
7%11%48%5%2445%6%37%
2278
16th to endNight
9%9%46%8%36%446%36%
2019
March1st to 15thNight
12%9%37%6%24346%39%
2026
16th to endNight
17%9%35%6%23346%35%
2094
April1st to 15thNight
18%9%45%423335%39%
1797
16th to endNight
23%8%35%32345%433%
1662
May1st to 15thNight
18%7%36%324446%38%
1481
16th to endNight
11%5%25%5%36%47%7%41%
1496
June1st to 15thNight
12%425%43346%7%44%
1440
16th to endNight
8%4244243410%50%
1272
July1st to 15thNight
43144245%6%8%54%
1362
16th to endNight
42134245%6%9%54%
1513
August1st to 15thNight
8%32442345%7%53%
1617
16th to endNight
11%424323336%53%
1786
September1st to 15thNight
7%32432345%6%54%
1750
16th to endNight
13%424423347%49%
1817
October1st to 15thNight
14%6%2432245%6%47%
1980
16th to endNight
20%9%26%42334437%
2135
November1st to 15thNight
13%9%36%5%2445%5%39%
2415
16th to endNight
15%9%47%6%34447%31%
2520
December1st to 15thNight
13%13%5%9%7%34445%28%
2520
16th to endNight
16%16%5%10%7%3445%5%21%
2688

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
53%7%12%19%7%
1433
16th to endDay
57%7%15%14%4
1659
February1st to 15thDay
51%5%13%21%6%1
1576
16th to endDay
53%6%11%21%6%
1452
March1st to 15thDay
50%5%17%19%6%
1944
16th to endDay
52%5%12%23%3
2130
April1st to 15thDay
48%411%20%13%1
2151
16th to endDay
56%5%10%16%9%
2295
May1st to 15thDay
55%6%10%19%7%
2469
16th to endDay
45%7%11%22%11%1
2621
June1st to 15thDay
41%7%14%27%7%
2520
16th to endDay
37%7%16%26%9%1
2682
July1st to 15thDay
29%7%14%30%16%1
2444
16th to endDay
30%8%17%26%15%1
2488
August1st to 15thDay
35%10%13%28%10%1
2326
16th to endDay
35%5%16%27%13%1
2415
September1st to 15thDay
33%8%13%34%9%
2097
16th to endDay
41%7%12%31%6%
1801
October1st to 15thDay
43%5%13%24%11%1
1650
16th to endDay
50%5%14%20%8%
1735
November1st to 15thDay
48%5%12%19%12%
1440
16th to endDay
52%8%17%15%5%1
1440
December1st to 15thDay
61%6%12%15%4
1440
16th to endDay
68%5%9%10%5%
1536
January1st to 15thNight
48%6%13%21%8%
2506
16th to endNight
56%414%17%5%
2562
February1st to 15thNight
45%5%15%24%7%
2288
16th to endNight
47%6%14%22%8%
2019
March1st to 15thNight
47%6%14%21%9%
2026
16th to endNight
49%5%13%24%6%
2094
April1st to 15thNight
46%49%23%14%1
1797
16th to endNight
51%7%8%18%12%2
1662
May1st to 15thNight
46%6%14%19%12%1
1482
16th to endNight
39%6%14%22%14%2
1498
June1st to 15thNight
35%7%14%28%11%2
1440
16th to endNight
28%8%13%30%15%4
1272
July1st to 15thNight
26%8%14%31%17%2
1284
16th to endNight
22%9%14%30%19%4
1417
August1st to 15thNight
29%5%12%32%14%4
1608
16th to endNight
31%5%13%29%15%3
1786
September1st to 15thNight
28%5%14%35%16%
1750
16th to endNight
34%5%14%32%11%
1817
October1st to 15thNight
36%411%32%14%1
1980
16th to endNight
48%5%13%21%11%
2135
November1st to 15thNight
45%411%23%13%
2415
16th to endNight
51%6%15%16%8%1
2520
December1st to 15thNight
58%5%14%17%4
2520
16th to endNight
64%412%13%5%
2688

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
18%11%30%26%10%3
90
16th to endDay
20%9%33%26%9%1
96
February1st to 15thDay
14%13%44%24%3
90
16th to endDay
23%11%35%22%6%1
81
March1st to 15thDay
20%6%32%31%8%1
90
16th to endDay
30%9%22%26%10%
114
April1st to 15thDay
21%9%28%27%11%1
270
16th to endDay
30%6%31%19%10%1
405
May1st to 15thDay
21%10%30%26%8%2
468
16th to endDay
20%6%30%21%14%5%
517
June1st to 15thDay
15%5%28%32%15%2
495
16th to endDay
10%431%31%15%5%
495
July1st to 15thDay
8%423%29%24%10%
475
16th to endDay
9%223%35%22%7%
515
August1st to 15thDay
10%120%34%26%6%
493
16th to endDay
16%319%32%19%7%
455
September1st to 15thDay
9%327%34%20%4
294
16th to endDay
20%8%27%24%11%7%
131
October1st to 15thDay
6%6%38%20%17%10%
90
16th to endDay
26%7%31%22%12%
96
November1st to 15thDay
7%7%26%37%17%2
90
16th to endDay
36%6%31%20%5%
90
December1st to 15thDay
20%5%34%32%7%
90
16th to endDay
34%10%38%15%1
96
January1st to 15thNight
15%9%33%30%9%2
900
16th to endNight
18%7%37%28%7%
960
February1st to 15thNight
13%8%35%31%10%1
880
16th to endNight
13%8%36%28%11%
757
March1st to 15thNight
16%8%34%30%9%
586
16th to endNight
21%7%30%27%11%2
576
April1st to 15thNight
22%7%32%29%7%
539
16th to endNight
27%430%26%9%1
540
May1st to 15thNight
19%9%32%29%8%
540
16th to endNight
13%6%28%34%15%1
563
June1st to 15thNight
13%227%43%12%
540
16th to endNight
10%422%43%18%
540
July1st to 15thNight
6%123%43%23%1
510
16th to endNight
6%119%46%24%1
564
August1st to 15thNight
11%112%47%25%2
539
16th to endNight
13%20%38%25%1
573
September1st to 15thNight
9%222%39%21%4
525
16th to endNight
13%6%29%28%20%1
536
October1st to 15thNight
18%7%28%30%13%1
660
16th to endNight
24%7%26%32%8%
704
November1st to 15thNight
17%9%31%30%9%
839
16th to endNight
20%10%31%28%9%
900
December1st to 15thNight
18%9%35%29%6%
900
16th to endNight
23%8%29%28%8%
960
Page generated at 2017-09-11 18:35:27. Version ac04

Copyright 2017 A. Danko


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