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 2005-11-06 to 2024-03-01.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	13% 9% 4 7% 6% 4 5% 5% 5% 7% 36%	78757
	Night	12% 9% 4 7% 6% 3 5% 4 5% 6% 38%	80687
Transparency	Day	46% 7% 13% 23% 10% 1	78456
	Night	46% 6% 13% 23% 11% 1	80509
Seeing	Day	16% 8% 29% 28% 15% 4	15010
	Night	16% 8% 31% 33% 12% 1	25129

By Month

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 13% 6% 13% 8% 4 5% 4 5% 6% 23%	2527
	11th to 20th	Day	6% 9% 6% 13% 11% 7% 9% 8% 6% 4 21%	2530
	21st to end	Day	7% 18% 9% 11% 6% 3 5% 5% 6% 6% 23%	3107
February	1st to 10th	Day	9% 10% 6% 9% 7% 4 5% 5% 5% 7% 33%	1710
	11th to 20th	Day	7% 11% 5% 8% 8% 3 5% 5% 5% 7% 36%	1664
	21st to end	Day	11% 11% 4 9% 7% 4 6% 4 5% 6% 34%	1462
March	1st to 10th	Day	12% 11% 5% 8% 7% 4 5% 5% 5% 8% 31%	1926
	11th to 20th	Day	14% 9% 4 6% 6% 3 5% 4 5% 8% 37%	1980
	21st to end	Day	18% 11% 4 7% 5% 3 4 5% 5% 5% 31%	2204
April	1st to 10th	Day	16% 11% 4 6% 6% 3 5% 4 5% 6% 34%	2160
	11th to 20th	Day	20% 11% 4 7% 6% 4 4 4 4 6% 31%	2155
	21st to end	Day	22% 8% 4 7% 6% 3 4 4 5% 5% 32%	2340
May	1st to 10th	Day	16% 9% 3 7% 6% 4 5% 5% 5% 6% 34%	2456
	11th to 20th	Day	17% 7% 3 6% 6% 3 4 5% 5% 8% 37%	2479
	21st to end	Day	13% 7% 3 6% 6% 4 4 5% 6% 8% 37%	2725
June	1st to 10th	Day	12% 5% 2 5% 5% 3 4 5% 6% 8% 45%	2520
	11th to 20th	Day	11% 7% 3 6% 5% 3 5% 6% 6% 8% 40%	2583
	21st to end	Day	9% 4 2 5% 6% 4 6% 6% 9% 10% 40%	2700
July	1st to 10th	Day	6% 3 2 4 4 3 5% 6% 6% 11% 50%	2633
	11th to 20th	Day	8% 4 2 5% 4 3 4 4 6% 8% 50%	2520
	21st to end	Day	6% 4 2 4 4 3 5% 5% 6% 11% 50%	2743
August	1st to 10th	Day	9% 4 2 5% 6% 3 6% 6% 7% 10% 42%	2328
	11th to 20th	Day	12% 5% 2 5% 5% 4 4 5% 6% 7% 44%	2301
	21st to end	Day	11% 4 2 4 4 2 4 4 5% 8% 51%	2473
September	1st to 10th	Day	9% 5% 2 5% 6% 4 5% 4 7% 7% 45%	2160
	11th to 20th	Day	12% 5% 2 5% 5% 3 5% 5% 6% 8% 45%	2138
	21st to end	Day	16% 6% 2 5% 5% 3 3 6% 5% 7% 42%	1890
October	1st to 10th	Day	18% 7% 3 4 4 3 4 6% 5% 7% 39%	1800
	11th to 20th	Day	15% 10% 3 7% 5% 4 4 5% 5% 5% 36%	1800
	21st to end	Day	19% 10% 4 7% 6% 3 3 4 4 5% 36%	1941
November	1st to 10th	Day	13% 10% 4 8% 6% 4 5% 5% 6% 6% 35%	1541
	11th to 20th	Day	13% 15% 6% 9% 7% 3 5% 4 5% 6% 28%	1520
	21st to end	Day	14% 11% 4 7% 6% 3 5% 5% 6% 6% 33%	1520
December	1st to 10th	Day	12% 12% 7% 9% 9% 4 6% 5% 5% 6% 25%	1520
	11th to 20th	Day	12% 13% 8% 9% 6% 4 5% 5% 5% 6% 26%	1918
	21st to end	Day	23% 15% 6% 13% 6% 4 3 4 3 5% 19%	2783
January	1st to 10th	Night	12% 12% 6% 13% 7% 3 4 3 4 6% 30%	4428
	11th to 20th	Night	7% 10% 5% 12% 9% 6% 9% 8% 7% 6% 22%	4440
	21st to end	Night	10% 21% 7% 10% 6% 3 4 4 4 5% 26%	4555
February	1st to 10th	Night	7% 11% 5% 9% 7% 4 5% 4 5% 7% 37%	2470
	11th to 20th	Night	6% 9% 4 8% 7% 3 6% 5% 6% 7% 39%	2403
	21st to end	Night	13% 10% 4 7% 8% 3 5% 5% 4 6% 36%	1990
March	1st to 10th	Night	11% 10% 3 7% 8% 4 5% 5% 4 6% 36%	2056
	11th to 20th	Night	13% 10% 3 7% 6% 2 4 3 4 6% 41%	1980
	21st to end	Night	18% 8% 4 6% 6% 2 4 4 4 6% 36%	2152
April	1st to 10th	Night	16% 11% 4 7% 5% 3 4 4 4 7% 36%	1800
	11th to 20th	Night	22% 9% 3 6% 4 3 4 4 4 5% 36%	1750
	21st to end	Night	20% 10% 3 6% 5% 3 4 5% 5% 6% 35%	1620
May	1st to 10th	Night	16% 8% 4 7% 4 3 4 4 5% 7% 39%	1504
	11th to 20th	Night	15% 5% 3 6% 4 2 5% 4 6% 8% 43%	1416
	21st to end	Night	13% 5% 2 5% 6% 3 5% 4 7% 7% 43%	1551
June	1st to 10th	Night	10% 4 2 5% 5% 3 5% 5% 6% 9% 46%	1440
	11th to 20th	Night	10% 5% 2 6% 5% 3 5% 5% 6% 8% 47%	1368
	21st to end	Night	7% 3 2 5% 5% 3 4 4 6% 10% 49%	1260
July	1st to 10th	Night	4 3 2 3 5% 2 3 5% 7% 9% 57%	1322
	11th to 20th	Night	6% 4 2 4 4 3 5% 5% 5% 9% 54%	1440
	21st to end	Night	3 3 2 3 5% 2 4 5% 6% 9% 59%	1575
August	1st to 10th	Night	7% 4 2 4 5% 3 4 4 5% 8% 52%	1607
	11th to 20th	Night	13% 4 2 4 2 3 3 4 5% 8% 52%	1600
	21st to end	Night	10% 4 2 5% 5% 3 4 4 3 6% 55%	1881
September	1st to 10th	Night	9% 4 2 5% 4 3 4 5% 5% 8% 52%	1800
	11th to 20th	Night	9% 3 2 5% 4 3 4 4 6% 7% 53%	1820
	21st to end	Night	15% 5% 2 4 4 3 4 4 4 7% 49%	2051
October	1st to 10th	Night	15% 6% 2 5% 4 3 3 5% 4 6% 47%	2160
	11th to 20th	Night	15% 10% 3 6% 4 3 4 4 5% 7% 38%	2160
	21st to end	Night	18% 9% 3 7% 6% 3 4 4 4 6% 37%	2413
November	1st to 10th	Night	14% 8% 4 6% 5% 3 5% 5% 6% 7% 39%	2532
	11th to 20th	Night	15% 11% 5% 10% 7% 4 4 3 4 5% 33%	2660
	21st to end	Night	13% 9% 3 7% 6% 3 4 5% 6% 8% 35%	2660
December	1st to 10th	Night	10% 13% 4 11% 8% 4 5% 4 5% 7% 30%	2660
	11th to 20th	Night	11% 15% 5% 9% 8% 4 5% 6% 5% 6% 26%	3279
	21st to end	Night	23% 16% 5% 9% 6% 3 4 4 4 4 23%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	61% 6% 11% 17% 5%	2528
	11th to 20th	Day	62% 5% 13% 15% 5%	2530
	21st to end	Day	59% 7% 13% 15% 5%	3107
February	1st to 10th	Day	50% 6% 12% 22% 8% 1	1710
	11th to 20th	Day	48% 5% 12% 25% 9% 1	1673
	21st to end	Day	51% 5% 11% 21% 10% 1	1462
March	1st to 10th	Day	51% 6% 15% 19% 8% 1	1926
	11th to 20th	Day	46% 5% 16% 23% 8% 1	1980
	21st to end	Day	54% 6% 10% 22% 7% 1	2204
April	1st to 10th	Day	50% 6% 11% 19% 13% 1	2160
	11th to 20th	Day	55% 5% 9% 18% 12% 2	2155
	21st to end	Day	54% 5% 11% 19% 10%	2340
May	1st to 10th	Day	50% 6% 11% 21% 10% 2	2456
	11th to 20th	Day	46% 6% 13% 22% 11% 1	2483
	21st to end	Day	44% 8% 10% 24% 12% 2	2725
June	1st to 10th	Day	35% 8% 14% 31% 11% 1	2520
	11th to 20th	Day	39% 8% 14% 24% 14% 1	2583
	21st to end	Day	35% 9% 18% 28% 9% 2	2700
July	1st to 10th	Day	27% 8% 15% 33% 16% 1	2562
	11th to 20th	Day	30% 7% 15% 27% 18% 2	2445
	21st to end	Day	28% 9% 16% 30% 17% 1	2591
August	1st to 10th	Day	34% 10% 14% 29% 10% 3	2314
	11th to 20th	Day	37% 8% 14% 30% 11%	2301
	21st to end	Day	31% 6% 15% 30% 16% 2	2473
September	1st to 10th	Day	35% 8% 14% 32% 11%	2160
	11th to 20th	Day	36% 9% 15% 32% 8%	2138
	21st to end	Day	40% 7% 12% 33% 8%	1890
October	1st to 10th	Day	43% 7% 12% 27% 10% 1	1800
	11th to 20th	Day	47% 6% 12% 22% 11% 2	1800
	21st to end	Day	49% 5% 13% 23% 9%	1941
November	1st to 10th	Day	49% 5% 12% 19% 13% 2	1541
	11th to 20th	Day	57% 6% 14% 15% 8%	1520
	21st to end	Day	50% 7% 15% 21% 5% 2	1520
December	1st to 10th	Day	59% 6% 14% 15% 5%	1520
	11th to 20th	Day	58% 6% 15% 16% 4	1915
	21st to end	Day	70% 5% 9% 11% 6%	2783
January	1st to 10th	Night	56% 5% 12% 19% 6% 1	4428
	11th to 20th	Night	60% 6% 12% 15% 6%	4440
	21st to end	Night	61% 5% 9% 19% 5% 1	4555
February	1st to 10th	Night	46% 5% 14% 23% 10% 1	2470
	11th to 20th	Night	43% 7% 15% 25% 10% 1	2404
	21st to end	Night	49% 5% 13% 21% 12% 1	1990
March	1st to 10th	Night	49% 6% 14% 22% 8%	2056
	11th to 20th	Night	45% 5% 12% 23% 14% 1	1980
	21st to end	Night	49% 5% 12% 23% 9% 1	2152
April	1st to 10th	Night	47% 5% 10% 21% 16% 1	1800
	11th to 20th	Night	50% 5% 8% 21% 14% 2	1750
	21st to end	Night	49% 7% 8% 21% 14% 2	1620
May	1st to 10th	Night	45% 6% 13% 20% 16% 1	1504
	11th to 20th	Night	40% 7% 14% 23% 15% 2	1417
	21st to end	Night	39% 7% 13% 23% 15% 3	1552
June	1st to 10th	Night	33% 8% 15% 29% 13% 2	1440
	11th to 20th	Night	34% 7% 15% 25% 18% 2	1368
	21st to end	Night	28% 9% 14% 31% 14% 4	1260
July	1st to 10th	Night	22% 8% 15% 36% 18% 1	1284
	11th to 20th	Night	25% 8% 13% 32% 17% 4	1392
	21st to end	Night	21% 8% 15% 33% 20% 4	1487
August	1st to 10th	Night	30% 7% 12% 33% 14% 5%	1598
	11th to 20th	Night	31% 6% 16% 31% 14% 2	1600
	21st to end	Night	31% 6% 12% 31% 18% 3	1881
September	1st to 10th	Night	29% 6% 14% 34% 16% 1	1800
	11th to 20th	Night	29% 6% 16% 33% 15%	1820
	21st to end	Night	35% 6% 13% 33% 12% 1	2051
October	1st to 10th	Night	38% 4 10% 32% 14% 2	2160
	11th to 20th	Night	44% 5% 13% 24% 12% 1	2160
	21st to end	Night	48% 6% 12% 22% 10% 1	2413
November	1st to 10th	Night	45% 5% 13% 24% 12% 2	2532
	11th to 20th	Night	54% 5% 13% 18% 10% 1	2660
	21st to end	Night	47% 7% 17% 21% 7% 1	2660
December	1st to 10th	Night	55% 6% 14% 19% 5%	2660
	11th to 20th	Night	58% 6% 12% 16% 5% 2	3281
	21st to end	Night	65% 5% 10% 15% 5%	4884

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 10% 30% 31% 11% 4	270
	11th to 20th	Day	14% 8% 38% 33% 7% 1	270
	21st to end	Day	14% 8% 38% 25% 13% 3	297
February	1st to 10th	Day	14% 11% 42% 26% 6% 1	270
	11th to 20th	Day	14% 14% 39% 24% 6% 2	270
	21st to end	Day	17% 11% 39% 28% 4	225
March	1st to 10th	Day	17% 13% 33% 27% 9% 2	240
	11th to 20th	Day	18% 7% 34% 27% 11% 3	240
	21st to end	Day	26% 13% 27% 21% 10% 3	290
April	1st to 10th	Day	22% 14% 31% 25% 7%	420
	11th to 20th	Day	26% 12% 25% 23% 12% 1	433
	21st to end	Day	26% 10% 30% 20% 10% 3	600
May	1st to 10th	Day	19% 11% 31% 27% 10% 2	603
	11th to 20th	Day	20% 10% 29% 27% 11% 4	625
	21st to end	Day	18% 8% 27% 27% 17% 4	679
June	1st to 10th	Day	11% 5% 26% 32% 20% 5%	630
	11th to 20th	Day	12% 6% 35% 33% 13% 2	630
	21st to end	Day	11% 6% 27% 33% 17% 7%	630
July	1st to 10th	Day	8% 4 21% 31% 25% 11%	621
	11th to 20th	Day	8% 5% 25% 31% 20% 10%	618
	21st to end	Day	7% 4 22% 35% 24% 8%	684
August	1st to 10th	Day	10% 2 21% 33% 26% 8%	626
	11th to 20th	Day	14% 4 18% 32% 25% 7%	615
	21st to end	Day	11% 6% 23% 33% 21% 6%	592
September	1st to 10th	Day	13% 5% 28% 29% 20% 4	450
	11th to 20th	Day	13% 6% 26% 29% 21% 5%	428
	21st to end	Day	21% 13% 26% 22% 11% 7%	270
October	1st to 10th	Day	19% 7% 28% 21% 16% 7%	270
	11th to 20th	Day	14% 16% 34% 26% 9% 2	270
	21st to end	Day	21% 13% 42% 15% 7% 2	297
November	1st to 10th	Day	20% 11% 34% 24% 10% 1	270
	11th to 20th	Day	17% 16% 41% 20% 4 1	270
	21st to end	Day	20% 12% 39% 23% 7%	270
December	1st to 10th	Day	14% 9% 41% 23% 12%	270
	11th to 20th	Day	19% 13% 36% 27% 6%	270
	21st to end	Day	28% 11% 34% 24% 3 1	297
January	1st to 10th	Night	13% 9% 35% 32% 9% 1	950
	11th to 20th	Night	15% 7% 37% 31% 8% 1	950
	21st to end	Night	18% 8% 36% 29% 9% 1	1045
February	1st to 10th	Night	11% 9% 39% 31% 10% 1	950
	11th to 20th	Night	10% 10% 41% 29% 8% 1	929
	21st to end	Night	17% 9% 34% 30% 9% 1	734
March	1st to 10th	Night	16% 9% 36% 29% 10%	612
	11th to 20th	Night	17% 9% 37% 30% 6% 1	540
	21st to end	Night	22% 8% 29% 28% 11% 2	594
April	1st to 10th	Night	19% 11% 35% 29% 7%	540
	11th to 20th	Night	27% 8% 30% 27% 8% 1	533
	21st to end	Night	23% 9% 29% 29% 9% 1	540
May	1st to 10th	Night	16% 11% 32% 33% 7%	540
	11th to 20th	Night	16% 8% 30% 33% 12% 1	531
	21st to end	Night	13% 8% 24% 38% 16% 1	584
June	1st to 10th	Night	13% 4 26% 44% 13% 1	540
	11th to 20th	Night	11% 3 29% 45% 12%	540
	21st to end	Night	9% 5% 22% 44% 19% 2	540
July	1st to 10th	Night	6% 1 19% 46% 25% 2	525
	11th to 20th	Night	7% 3 23% 45% 21% 1	522
	21st to end	Night	5% 2 20% 48% 22% 3	591
August	1st to 10th	Night	9% 2 14% 53% 21% 2	537
	11th to 20th	Night	16% 1 19% 34% 28% 3	534
	21st to end	Night	11% 2 21% 39% 25% 2	594
September	1st to 10th	Night	11% 3 22% 42% 19% 4	540
	11th to 20th	Night	9% 5% 30% 34% 20% 2	540
	21st to end	Night	17% 8% 31% 30% 14% 1	611
October	1st to 10th	Night	20% 7% 28% 31% 14% 1	720
	11th to 20th	Night	20% 10% 34% 28% 8% 1	720
	21st to end	Night	22% 9% 30% 31% 7%	792
November	1st to 10th	Night	17% 11% 31% 32% 9%	866
	11th to 20th	Night	19% 11% 35% 27% 8% 1	950
	21st to end	Night	18% 11% 36% 27% 8%	950
December	1st to 10th	Night	15% 9% 34% 33% 8% 1	950
	11th to 20th	Night	18% 9% 37% 27% 8% 1	950
	21st to end	Night	26% 8% 33% 26% 6%	1045

Page generated at 2024-02-27 05:30:19. Version ac07

Copyright © 2024 Attilla Danko.