Maple Plains
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Maple Plains clear sky chart from 2005-11-06 to 2024-12-06.

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 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	17% 11% 4 8% 5% 5% 5% 4 5% 7% 31%	102182
	Night	19% 11% 4 9% 5% 4 4 4 5% 6% 29%	97577
Transparency	Day	28% 48% 8% 11% 4	105736
	Night	29% 49% 8% 9% 4	102115
Seeing	Day	22% 10% 29% 27% 11% 2	17297
	Night	23% 12% 30% 26% 8% 1	24660

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 14% 7% 15% 6% 7% 6% 4 5% 5% 19%	2245
	11th to 20th	Day	13% 13% 5% 12% 7% 5% 5% 3 4 5% 29%	2530
	21st to end	Day	12% 9% 4 13% 6% 5% 5% 4 5% 6% 31%	3071
February	1st to 10th	Day	17% 13% 4 9% 5% 4 4 4 5% 5% 30%	1710
	11th to 20th	Day	16% 15% 4 9% 5% 5% 5% 4 5% 5% 28%	1663
	21st to end	Day	11% 11% 5% 8% 5% 5% 5% 3 6% 7% 32%	1438
March	1st to 10th	Day	21% 13% 5% 7% 4 6% 3 3 5% 6% 29%	3356
	11th to 20th	Day	11% 17% 7% 13% 7% 5% 5% 4 5% 5% 21%	3480
	21st to end	Day	24% 16% 4 9% 5% 4 3 4 6% 5% 22%	3846
April	1st to 10th	Day	19% 13% 4 7% 5% 4 4 3 4 6% 30%	2280
	11th to 20th	Day	18% 12% 3 6% 5% 4 4 3 5% 7% 34%	2330
	21st to end	Day	20% 12% 3 7% 4 4 4 4 5% 6% 31%	2470
May	1st to 10th	Day	22% 16% 3 7% 4 3 4 3 4 6% 28%	4324
	11th to 20th	Day	17% 9% 3 7% 5% 5% 5% 3 5% 6% 37%	4398
	21st to end	Day	17% 9% 3 8% 5% 5% 5% 4 6% 7% 30%	4836
June	1st to 10th	Day	25% 11% 3 7% 5% 5% 5% 4 6% 6% 25%	2706
	11th to 20th	Day	20% 9% 3 6% 5% 4 4 3 5% 7% 35%	2850
	21st to end	Day	24% 9% 3 7% 4 3 5% 3 5% 6% 30%	2850
July	1st to 10th	Day	15% 8% 3 7% 5% 5% 5% 4 7% 8% 33%	4760
	11th to 20th	Day	16% 7% 2 6% 5% 4 5% 4 7% 8% 36%	4517
	21st to end	Day	13% 7% 3 6% 4 4 5% 4 7% 9% 37%	4815
August	1st to 10th	Day	17% 9% 3 8% 5% 4 5% 4 6% 7% 31%	4120
	11th to 20th	Day	14% 7% 2 7% 4 5% 5% 5% 6% 8% 38%	4045
	21st to end	Day	11% 5% 2 4 4 4 5% 4 6% 8% 44%	4354
September	1st to 10th	Day	17% 5% 2 5% 4 4 4 4 6% 8% 41%	2280
	11th to 20th	Day	18% 8% 2 7% 4 4 4 4 4 7% 39%	2241
	21st to end	Day	18% 7% 2 7% 4 5% 4 3 5% 7% 39%	2009
October	1st to 10th	Day	18% 8% 3 6% 5% 5% 4 4 6% 8% 34%	1900
	11th to 20th	Day	19% 11% 4 8% 5% 5% 5% 4 5% 8% 27%	1900
	21st to end	Day	17% 13% 4 10% 6% 5% 5% 3 4 7% 24%	2047
November	1st to 10th	Day	19% 13% 3 8% 5% 6% 5% 4 5% 5% 25%	1586
	11th to 20th	Day	20% 16% 5% 10% 5% 5% 5% 3 5% 7% 20%	1600
	21st to end	Day	18% 16% 5% 12% 6% 6% 5% 5% 5% 6% 18%	1600
December	1st to 10th	Day	22% 16% 6% 11% 5% 5% 4 3 5% 6% 18%	1560
	11th to 20th	Day	21% 16% 6% 12% 8% 6% 5% 3 4 4 16%	1906
	21st to end	Day	18% 14% 6% 15% 6% 5% 5% 3 5% 6% 18%	2559
January	1st to 10th	Night	12% 12% 5% 11% 6% 6% 6% 4 6% 6% 26%	4689
	11th to 20th	Night	17% 14% 5% 10% 5% 5% 4 3 5% 5% 27%	4440
	21st to end	Night	12% 13% 4 13% 6% 4 5% 4 5% 6% 28%	4584
February	1st to 10th	Night	17% 14% 4 9% 5% 4 4 3 5% 5% 29%	2470
	11th to 20th	Night	17% 16% 4 9% 7% 5% 5% 3 5% 5% 25%	2403
	21st to end	Night	12% 13% 4 8% 6% 5% 4 4 5% 5% 33%	2015
March	1st to 10th	Night	20% 13% 3 11% 6% 4 4 3 4 5% 25%	3481
	11th to 20th	Night	18% 16% 7% 12% 6% 5% 4 3 4 4 19%	3479
	21st to end	Night	26% 14% 5% 9% 4 4 4 4 4 3 23%	3785
April	1st to 10th	Night	23% 12% 4 9% 5% 4 3 4 5% 5% 26%	1900
	11th to 20th	Night	20% 12% 3 7% 5% 4 4 3 4 6% 32%	1797
	21st to end	Night	23% 13% 4 7% 5% 3 3 3 5% 5% 30%	1710
May	1st to 10th	Night	23% 14% 4 9% 5% 4 4 4 4 5% 24%	2621
	11th to 20th	Night	16% 7% 2 8% 5% 5% 4 3 5% 7% 39%	2506
	21st to end	Night	18% 8% 3 8% 5% 5% 5% 3 6% 9% 29%	2749
June	1st to 10th	Night	26% 10% 3 7% 5% 5% 4 4 4 5% 27%	1488
	11th to 20th	Night	18% 8% 2 6% 4 3 4 3 5% 8% 38%	1330
	21st to end	Night	22% 11% 3 8% 5% 3 4 4 6% 6% 28%	1330
July	1st to 10th	Night	15% 8% 3 8% 6% 5% 7% 5% 7% 8% 29%	2210
	11th to 20th	Night	14% 7% 3 6% 6% 5% 5% 6% 7% 9% 33%	2420
	21st to end	Night	14% 7% 2 6% 4 3 5% 3 5% 7% 43%	2750
August	1st to 10th	Night	19% 9% 4 7% 6% 5% 5% 4 5% 7% 29%	2794
	11th to 20th	Night	10% 7% 3 7% 5% 5% 4 4 7% 9% 40%	2782
	21st to end	Night	12% 6% 2 6% 4 4 5% 3 6% 8% 44%	3302
September	1st to 10th	Night	16% 6% 2 6% 4 4 4 3 4 8% 43%	1900
	11th to 20th	Night	17% 6% 2 6% 4 4 4 3 4 6% 43%	1937
	21st to end	Night	18% 6% 2 5% 3 4 4 4 5% 7% 42%	2171
October	1st to 10th	Night	20% 7% 2 8% 4 4 4 3 5% 7% 38%	2280
	11th to 20th	Night	19% 9% 4 7% 5% 4 5% 3 5% 5% 35%	2280
	21st to end	Night	23% 12% 3 8% 5% 4 5% 3 4 5% 28%	2550
November	1st to 10th	Night	22% 12% 3 7% 5% 4 5% 4 4 6% 28%	2709
	11th to 20th	Night	21% 14% 4 9% 4 5% 4 3 5% 6% 24%	2800
	21st to end	Night	23% 16% 4 9% 5% 4 4 3 5% 6% 21%	2800
December	1st to 10th	Night	23% 13% 5% 11% 7% 5% 5% 4 6% 5% 16%	2737
	11th to 20th	Night	25% 16% 5% 10% 6% 4 4 4 4 4 18%	3293
	21st to end	Night	24% 16% 5% 12% 5% 4 3 3 4 4 20%	5085

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	43% 45% 6% 3 2	2246
	11th to 20th	Day	29% 42% 9% 13% 7% 1	2530
	21st to end	Day	31% 44% 11% 7% 6% 1	3071
February	1st to 10th	Day	20% 65% 3 8% 3 1	1710
	11th to 20th	Day	20% 65% 4 7% 4	1671
	21st to end	Day	16% 65% 4 8% 5% 1	1438
March	1st to 10th	Day	33% 42% 7% 14% 3 1	3360
	11th to 20th	Day	39% 46% 6% 7% 3	3480
	21st to end	Day	40% 43% 6% 8% 3 1	3846
April	1st to 10th	Day	21% 65% 3 5% 4 2	2280
	11th to 20th	Day	18% 66% 3 8% 4	2330
	21st to end	Day	21% 65% 4 5% 4 1	2470
May	1st to 10th	Day	33% 43% 11% 10% 3	4339
	11th to 20th	Day	26% 44% 10% 16% 3	4402
	21st to end	Day	29% 46% 10% 10% 4	4836
June	1st to 10th	Day	19% 66% 4 8% 3	2706
	11th to 20th	Day	17% 65% 6% 9% 3	2850
	21st to end	Day	19% 64% 4 7% 6%	2850
July	1st to 10th	Day	33% 38% 12% 9% 8% 1	4685
	11th to 20th	Day	30% 38% 11% 17% 4	4438
	21st to end	Day	24% 41% 13% 17% 5%	4662
August	1st to 10th	Day	35% 39% 8% 16% 2	4106
	11th to 20th	Day	27% 40% 8% 15% 9%	4084
	21st to end	Day	22% 39% 10% 18% 11%	4354
September	1st to 10th	Day	14% 61% 7% 13% 5%	2280
	11th to 20th	Day	21% 60% 6% 9% 4	2241
	21st to end	Day	16% 61% 5% 12% 6%	2009
October	1st to 10th	Day	30% 39% 9% 17% 5%	3160
	11th to 20th	Day	32% 39% 7% 18% 5%	3140
	21st to end	Day	29% 38% 15% 13% 5%	3352
November	1st to 10th	Day	27% 58% 5% 7% 2	1586
	11th to 20th	Day	33% 58% 5% 2 2	1600
	21st to end	Day	30% 59% 6% 3 1	1600
December	1st to 10th	Day	30% 61% 4 5% 1	1560
	11th to 20th	Day	39% 51% 4 4 2	1905
	21st to end	Day	43% 40% 8% 5% 2	2559
January	1st to 10th	Night	30% 50% 11% 7% 2	4689
	11th to 20th	Night	31% 43% 9% 12% 5%	4440
	21st to end	Night	36% 47% 8% 6% 3	4584
February	1st to 10th	Night	22% 65% 3 5% 4 1	2470
	11th to 20th	Night	21% 64% 3 7% 4	2406
	21st to end	Night	17% 65% 3 7% 6% 2	2015
March	1st to 10th	Night	35% 42% 6% 11% 5% 1	3490
	11th to 20th	Night	43% 45% 5% 4 3 1	3480
	21st to end	Night	42% 43% 3 8% 4	3785
April	1st to 10th	Night	21% 65% 3 5% 4 1	1900
	11th to 20th	Night	19% 66% 4 7% 3 1	1797
	21st to end	Night	21% 65% 3 5% 5% 1	1710
May	1st to 10th	Night	39% 46% 6% 7% 3	2626
	11th to 20th	Night	23% 44% 14% 15% 5%	2507
	21st to end	Night	30% 47% 13% 7% 3	2750
June	1st to 10th	Night	19% 65% 5% 7% 3	1488
	11th to 20th	Night	15% 65% 5% 10% 4	1330
	21st to end	Night	20% 64% 3 8% 4	1330
July	1st to 10th	Night	35% 39% 9% 9% 5% 2	2175
	11th to 20th	Night	29% 40% 14% 13% 3	2376
	21st to end	Night	22% 39% 15% 16% 8%	2663
August	1st to 10th	Night	38% 39% 10% 11% 2	2783
	11th to 20th	Night	24% 42% 12% 13% 8% 1	2809
	21st to end	Night	24% 38% 12% 16% 10%	3301
September	1st to 10th	Night	15% 61% 5% 13% 6%	1900
	11th to 20th	Night	19% 61% 6% 11% 4	1937
	21st to end	Night	15% 61% 5% 13% 5%	2171
October	1st to 10th	Night	32% 38% 10% 15% 4	3800
	11th to 20th	Night	25% 39% 8% 19% 8%	3779
	21st to end	Night	29% 38% 13% 14% 7%	4198
November	1st to 10th	Night	27% 58% 6% 6% 2	2709
	11th to 20th	Night	29% 59% 6% 5% 1	2800
	21st to end	Night	31% 59% 6% 3 1	2800
December	1st to 10th	Night	29% 60% 6% 4 1	2737
	11th to 20th	Night	36% 51% 4 6% 2	3295
	21st to end	Night	43% 39% 8% 7% 2	5085

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	21% 20% 33% 20% 5%	205
	11th to 20th	Day	25% 16% 33% 20% 6% 1	370
	21st to end	Day	16% 11% 38% 28% 5%	407
February	1st to 10th	Day	28% 12% 33% 19% 6% 2	370
	11th to 20th	Day	22% 16% 35% 22% 5%	366
	21st to end	Day	17% 12% 31% 31% 7% 1	307
March	1st to 10th	Day	23% 11% 32% 28% 5% 1	437
	11th to 20th	Day	16% 13% 34% 26% 10% 1	460
	21st to end	Day	25% 15% 27% 23% 9% 1	506
April	1st to 10th	Day	26% 13% 33% 20% 6%	460
	11th to 20th	Day	20% 12% 33% 23% 10% 2	452
	21st to end	Day	22% 12% 26% 26% 13% 1	460
May	1st to 10th	Day	30% 7% 30% 23% 8% 2	591
	11th to 20th	Day	21% 6% 26% 29% 15% 2	674
	21st to end	Day	23% 9% 29% 28% 10% 1	735
June	1st to 10th	Day	30% 7% 23% 27% 11% 1	680
	11th to 20th	Day	21% 6% 28% 33% 10% 2	680
	21st to end	Day	27% 4 23% 31% 12% 3	680
July	1st to 10th	Day	19% 4 28% 32% 15% 3	670
	11th to 20th	Day	17% 5% 24% 33% 18% 3	668
	21st to end	Day	18% 4 22% 38% 16% 2	740
August	1st to 10th	Day	13% 5% 22% 39% 17% 4	501
	11th to 20th	Day	17% 3 24% 32% 18% 6%	479
	21st to end	Day	15% 6% 25% 31% 18% 5%	539
September	1st to 10th	Day	16% 6% 30% 32% 14% 3	490
	11th to 20th	Day	21% 8% 26% 29% 15% 1	490
	21st to end	Day	18% 10% 28% 26% 14% 3	447
October	1st to 10th	Day	19% 12% 25% 24% 18% 2	390
	11th to 20th	Day	24% 15% 28% 21% 11% 2	390
	21st to end	Day	21% 19% 32% 21% 7% 1	429
November	1st to 10th	Day	23% 18% 33% 20% 5% 1	395
	11th to 20th	Day	34% 18% 27% 16% 4 1	400
	21st to end	Day	27% 19% 34% 18% 3	400
December	1st to 10th	Day	29% 15% 34% 19% 3	385
	11th to 20th	Day	28% 24% 34% 13% 2	370
	21st to end	Day	23% 19% 36% 18% 3 1	274
January	1st to 10th	Night	25% 15% 35% 20% 5%	850
	11th to 20th	Night	24% 17% 32% 22% 5%	850
	21st to end	Night	18% 13% 35% 25% 8% 1	848
February	1st to 10th	Night	25% 13% 33% 22% 6% 1	760
	11th to 20th	Night	23% 14% 38% 22% 3 1	743
	21st to end	Night	19% 11% 33% 28% 9% 1	628
March	1st to 10th	Night	23% 10% 37% 27% 3	760
	11th to 20th	Night	20% 13% 29% 29% 8% 1	760
	21st to end	Night	26% 12% 27% 25% 9% 1	817
April	1st to 10th	Night	27% 10% 32% 25% 5%	570
	11th to 20th	Night	26% 7% 30% 27% 9% 1	564
	21st to end	Night	27% 8% 30% 26% 8% 1	570
May	1st to 10th	Night	29% 7% 29% 23% 10% 2	570
	11th to 20th	Night	21% 7% 27% 31% 12% 2	562
	21st to end	Night	18% 8% 37% 31% 6%	616
June	1st to 10th	Night	28% 9% 27% 30% 7% 1	538
	11th to 20th	Night	20% 5% 27% 38% 10% 1	380
	21st to end	Night	26% 4 26% 35% 9% 1	380
July	1st to 10th	Night	17% 5% 29% 35% 12% 1	370
	11th to 20th	Night	14% 4 32% 39% 11% 1	485
	21st to end	Night	17% 4 24% 40% 15%	623
August	1st to 10th	Night	16% 4 28% 36% 16% 1	568
	11th to 20th	Night	15% 4 27% 35% 18% 1	562
	21st to end	Night	16% 6% 22% 36% 19% 1	627
September	1st to 10th	Night	18% 6% 31% 33% 11% 1	570
	11th to 20th	Night	20% 8% 21% 37% 13% 1	607
	21st to end	Night	19% 10% 29% 31% 10% 1	760
October	1st to 10th	Night	23% 9% 28% 29% 11%	760
	11th to 20th	Night	22% 13% 30% 25% 9% 1	760
	21st to end	Night	29% 18% 27% 20% 5%	859
November	1st to 10th	Night	28% 16% 31% 19% 4 1	880
	11th to 20th	Night	28% 20% 26% 20% 5% 1	900
	21st to end	Night	31% 20% 26% 19% 3	900
December	1st to 10th	Night	28% 19% 30% 18% 4	878
	11th to 20th	Night	26% 23% 31% 16% 3	850
	21st to end	Night	30% 16% 31% 19% 4 1	935

Page generated at 2024-12-03 07:45:08. Version ac07

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