Maramec Spring Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Maramec Spring Park clear sky chart from 2005-11-06 to 2024-11-10.

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 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	12% 8% 2 6% 4 4 4 4 5% 7% 43%	101216
	Night	13% 8% 3 6% 4 4 4 3 5% 6% 45%	98015
Transparency	Day	39% 5% 11% 25% 17% 3	104851
	Night	39% 5% 11% 24% 18% 3	102520
Seeing	Day	17% 12% 28% 25% 14% 4	15605
	Night	17% 12% 31% 26% 12% 1	25409

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	11% 13% 4 10% 4 3 4 4 4 5% 37%	2602
	11th to 20th	Day	12% 12% 4 8% 4 4 4 2 5% 5% 40%	2850
	21st to end	Day	21% 12% 5% 6% 3 3 3 3 4 5% 35%	3135
February	1st to 10th	Day	14% 13% 4 9% 5% 4 4 3 4 7% 34%	1710
	11th to 20th	Day	14% 10% 3 5% 4 4 4 4 5% 6% 39%	1779
	21st to end	Day	13% 12% 3 7% 4 3 4 3 5% 6% 39%	1570
March	1st to 10th	Day	18% 11% 4 6% 4 4 3 2 3 4 41%	3327
	11th to 20th	Day	13% 7% 2 5% 3 3 3 3 4 7% 51%	3480
	21st to end	Day	15% 9% 3 7% 6% 5% 5% 4 5% 6% 35%	3928
April	1st to 10th	Day	11% 7% 3 6% 4 4 4 4 6% 8% 44%	2280
	11th to 20th	Day	17% 8% 2 6% 4 5% 4 3 6% 6% 41%	2254
	21st to end	Day	19% 8% 3 7% 5% 4 4 4 6% 6% 35%	2280
May	1st to 10th	Day	14% 8% 2 7% 5% 5% 5% 5% 7% 9% 33%	3820
	11th to 20th	Day	17% 7% 3 6% 4 4 4 4 4 8% 39%	4296
	21st to end	Day	11% 7% 2 6% 4 5% 5% 4 5% 7% 43%	4824
June	1st to 10th	Day	9% 5% 2 6% 5% 5% 5% 5% 6% 8% 44%	2660
	11th to 20th	Day	7% 4 2 5% 4 4 4 4 7% 10% 49%	2660
	21st to end	Day	6% 3 1 5% 4 4 6% 5% 8% 9% 49%	2660
July	1st to 10th	Day	12% 6% 2 6% 4 5% 5% 4 6% 10% 40%	4440
	11th to 20th	Day	3 4 2 6% 4 5% 5% 5% 7% 11% 48%	4293
	21st to end	Day	7% 6% 2 7% 5% 6% 7% 5% 8% 11% 37%	4465
August	1st to 10th	Day	5% 3 2 5% 4 4 4 5% 7% 11% 51%	4104
	11th to 20th	Day	11% 6% 2 6% 5% 5% 4 4 5% 8% 44%	3792
	21st to end	Day	7% 5% 2 5% 4 4 4 4 6% 8% 51%	4180
September	1st to 10th	Day	12% 5% 2 4 4 4 4 3 5% 8% 49%	2280
	11th to 20th	Day	11% 5% 2 6% 4 4 4 4 5% 7% 49%	2280
	21st to end	Day	8% 5% 2 6% 4 3 4 4 4 7% 51%	2023
October	1st to 10th	Day	10% 5% 1 4 4 4 3 3 3 6% 57%	1900
	11th to 20th	Day	14% 7% 1 5% 3 3 3 2 3 5% 54%	1900
	21st to end	Day	16% 8% 2 5% 3 3 3 3 4 5% 47%	2090
November	1st to 10th	Day	13% 5% 2 6% 3 3 3 3 4 5% 53%	1831
	11th to 20th	Day	14% 8% 3 5% 4 3 3 2 5% 7% 47%	1710
	21st to end	Day	14% 10% 3 5% 4 3 3 3 4 5% 45%	1592
December	1st to 10th	Day	13% 11% 3 6% 4 4 4 3 5% 6% 41%	1520
	11th to 20th	Day	13% 11% 5% 7% 5% 4 4 3 4 6% 39%	1918
	21st to end	Day	15% 16% 5% 10% 5% 4 4 3 4 6% 29%	2783
January	1st to 10th	Night	13% 11% 5% 10% 5% 4 4 3 4 5% 36%	4350
	11th to 20th	Night	13% 9% 4 12% 5% 5% 7% 4 4 4 33%	4120
	21st to end	Night	22% 13% 6% 7% 4 3 2 2 4 4 33%	4532
February	1st to 10th	Night	16% 10% 4 8% 4 4 3 3 5% 5% 37%	2470
	11th to 20th	Night	14% 8% 4 8% 4 3 2 3 5% 6% 43%	2288
	21st to end	Night	15% 10% 3 8% 5% 3 3 3 5% 5% 40%	1884
March	1st to 10th	Night	20% 11% 2 5% 3 2 3 2 4 4 45%	3555
	11th to 20th	Night	13% 7% 2 5% 3 3 3 3 5% 6% 50%	3480
	21st to end	Night	16% 11% 4 8% 5% 5% 5% 4 5% 6% 31%	3701
April	1st to 10th	Night	10% 6% 2 5% 4 3 4 4 5% 8% 50%	1900
	11th to 20th	Night	13% 9% 3 5% 4 3 3 4 5% 6% 46%	1875
	21st to end	Night	19% 7% 3 5% 5% 4 4 4 5% 7% 39%	1900
May	1st to 10th	Night	17% 8% 2 5% 3 3 3 4 5% 7% 42%	3073
	11th to 20th	Night	13% 9% 3 6% 3 3 4 3 5% 8% 43%	2607
	21st to end	Night	12% 7% 3 7% 5% 6% 5% 4 6% 7% 39%	2743
June	1st to 10th	Night	8% 4 2 6% 4 4 4 4 6% 8% 51%	1520
	11th to 20th	Night	5% 3 1 4 3 3 3 5% 7% 11% 54%	1520
	21st to end	Night	4 2 1 3 4 3 5% 4 6% 8% 60%	1520
July	1st to 10th	Night	11% 5% 2 6% 3 4 4 4 6% 10% 45%	2530
	11th to 20th	Night	5% 3 1 4 3 2 4 3 6% 8% 61%	2673
	21st to end	Night	6% 5% 2 7% 5% 5% 4 5% 7% 10% 43%	3098
August	1st to 10th	Night	4 3 1 4 3 4 3 3 6% 8% 60%	2836
	11th to 20th	Night	9% 6% 2 6% 4 4 4 3 6% 9% 48%	3037
	21st to end	Night	5% 3 1 4 4 3 4 3 5% 9% 58%	3476
September	1st to 10th	Night	11% 5% 1 5% 4 4 4 3 4 6% 54%	1900
	11th to 20th	Night	8% 6% 2 6% 4 3 3 3 6% 7% 51%	1900
	21st to end	Night	9% 5% 2 5% 4 3 4 3 4 6% 55%	2132
October	1st to 10th	Night	7% 3 1 4 3 3 3 3 5% 8% 61%	2280
	11th to 20th	Night	15% 6% 2 4 3 3 3 2 4 5% 54%	2280
	21st to end	Night	18% 7% 2 4 3 3 3 2 4 5% 49%	2508
November	1st to 10th	Night	11% 6% 2 5% 3 3 3 2 4 5% 56%	2450
	11th to 20th	Night	14% 7% 2 5% 3 3 4 2 5% 7% 49%	2470
	21st to end	Night	15% 11% 2 5% 4 3 3 3 4 5% 45%	2584
December	1st to 10th	Night	16% 10% 3 7% 5% 3 3 4 5% 7% 38%	2660
	11th to 20th	Night	14% 11% 4 7% 5% 3 4 3 5% 4 41%	3279
	21st to end	Night	15% 19% 5% 10% 5% 4 4 4 4 5% 24%	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	49% 5% 9% 24% 13% 1	2603
	11th to 20th	Day	46% 4 9% 25% 15% 1	2850
	21st to end	Day	52% 4 9% 16% 15% 4	3135
February	1st to 10th	Day	51% 4 10% 22% 12% 1	1710
	11th to 20th	Day	46% 5% 11% 20% 14% 5%	1788
	21st to end	Day	46% 4 7% 23% 14% 5%	1570
March	1st to 10th	Day	48% 4 6% 20% 15% 8%	3327
	11th to 20th	Day	35% 4 10% 28% 15% 7%	3480
	21st to end	Day	48% 7% 14% 20% 10% 1	3928
April	1st to 10th	Day	37% 6% 13% 24% 19% 1	2280
	11th to 20th	Day	44% 5% 11% 22% 15% 3	2254
	21st to end	Day	49% 6% 11% 20% 13% 1	2280
May	1st to 10th	Day	45% 9% 13% 20% 12% 1	3855
	11th to 20th	Day	44% 7% 11% 24% 13% 1	4300
	21st to end	Day	39% 8% 10% 24% 19% 1	4837
June	1st to 10th	Day	36% 8% 14% 26% 16% 2	2660
	11th to 20th	Day	28% 7% 13% 29% 19% 4	2660
	21st to end	Day	28% 7% 17% 27% 16% 5%	2660
July	1st to 10th	Day	40% 6% 12% 28% 12% 2	4371
	11th to 20th	Day	29% 6% 14% 33% 16% 2	4218
	21st to end	Day	40% 5% 19% 27% 8% 1	4325
August	1st to 10th	Day	27% 6% 17% 31% 19%	4090
	11th to 20th	Day	40% 5% 12% 25% 17% 2	3829
	21st to end	Day	31% 4 15% 35% 12% 4	4179
September	1st to 10th	Day	33% 7% 11% 26% 19% 5%	2280
	11th to 20th	Day	35% 5% 8% 25% 26% 2	2280
	21st to end	Day	32% 5% 9% 25% 24% 3	2023
October	1st to 10th	Day	18% 3 5% 19% 43% 11%	3160
	11th to 20th	Day	23% 2 6% 22% 36% 11%	3140
	21st to end	Day	32% 3 7% 30% 26% 3	3428
November	1st to 10th	Day	34% 4 10% 22% 23% 6%	1831
	11th to 20th	Day	39% 3 8% 23% 22% 6%	1710
	21st to end	Day	42% 4 9% 27% 17% 1	1592
December	1st to 10th	Day	44% 4 10% 27% 13% 2	1520
	11th to 20th	Day	47% 4 9% 19% 20% 1	1915
	21st to end	Day	57% 5% 10% 16% 11% 2	2783
January	1st to 10th	Night	51% 4 9% 21% 13% 1	4350
	11th to 20th	Night	54% 5% 9% 21% 10% 2	4120
	21st to end	Night	56% 4 9% 20% 10% 1	4532
February	1st to 10th	Night	50% 5% 10% 20% 14% 2	2470
	11th to 20th	Night	43% 4 11% 22% 17% 3	2289
	21st to end	Night	47% 4 9% 20% 15% 4	1884
March	1st to 10th	Night	45% 4 8% 23% 16% 5%	3555
	11th to 20th	Night	36% 5% 10% 25% 20% 4	3480
	21st to end	Night	51% 8% 12% 22% 7%	3701
April	1st to 10th	Night	33% 5% 12% 27% 20% 3	1900
	11th to 20th	Night	38% 5% 11% 25% 16% 5%	1875
	21st to end	Night	44% 6% 9% 24% 16% 1	1900
May	1st to 10th	Night	40% 8% 15% 21% 14% 2	3103
	11th to 20th	Night	40% 7% 13% 25% 14% 1	2608
	21st to end	Night	41% 8% 13% 22% 14% 2	2751
June	1st to 10th	Night	31% 6% 17% 26% 18% 3	1520
	11th to 20th	Night	22% 8% 13% 30% 22% 4	1520
	21st to end	Night	20% 7% 19% 28% 20% 7%	1520
July	1st to 10th	Night	36% 6% 13% 27% 16% 3	2490
	11th to 20th	Night	21% 4 12% 40% 20% 2	2625
	21st to end	Night	36% 5% 18% 28% 12% 1	2999
August	1st to 10th	Night	22% 5% 18% 31% 22% 1	2826
	11th to 20th	Night	34% 4 16% 27% 16% 3	3066
	21st to end	Night	24% 4 15% 38% 16% 3	3476
September	1st to 10th	Night	31% 5% 9% 26% 23% 6%	1900
	11th to 20th	Night	32% 5% 10% 23% 28% 2	1900
	21st to end	Night	30% 6% 9% 25% 27% 3	2132
October	1st to 10th	Night	14% 3 7% 17% 49% 11%	3800
	11th to 20th	Night	23% 2 6% 21% 34% 14%	3779
	21st to end	Night	33% 2 7% 27% 27% 3	4120
November	1st to 10th	Night	32% 4 10% 27% 21% 6%	2450
	11th to 20th	Night	37% 3 7% 24% 24% 5%	2470
	21st to end	Night	43% 4 9% 24% 18% 2	2584
December	1st to 10th	Night	46% 5% 11% 22% 15% 2	2660
	11th to 20th	Night	47% 4 8% 24% 15% 1	3281
	21st to end	Night	61% 6% 9% 14% 8% 2	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	27% 23% 35% 12% 2	270
	11th to 20th	Day	33% 21% 35% 10%	270
	21st to end	Day	23% 28% 34% 13% 2	297
February	1st to 10th	Day	26% 22% 36% 14% 1	270
	11th to 20th	Day	27% 29% 29% 11% 3	270
	21st to end	Day	28% 25% 36% 10% 1	225
March	1st to 10th	Day	23% 24% 42% 10% 1	270
	11th to 20th	Day	30% 22% 33% 11% 2 1	270
	21st to end	Day	31% 21% 36% 11% 1	360
April	1st to 10th	Day	21% 19% 37% 18% 5%	460
	11th to 20th	Day	27% 19% 30% 17% 6% 1	452
	21st to end	Day	23% 21% 30% 20% 5% 1	460
May	1st to 10th	Day	21% 17% 34% 21% 6% 1	492
	11th to 20th	Day	18% 15% 28% 25% 12% 2	675
	21st to end	Day	11% 12% 34% 23% 14% 5%	734
June	1st to 10th	Day	11% 6% 26% 28% 22% 6%	680
	11th to 20th	Day	8% 4 26% 37% 21% 3	680
	21st to end	Day	6% 7% 31% 36% 15% 4	680
July	1st to 10th	Day	13% 4 17% 29% 27% 10%	671
	11th to 20th	Day	5% 4 21% 38% 26% 6%	668
	21st to end	Day	11% 3 17% 35% 28% 7%	739
August	1st to 10th	Day	11% 2 18% 39% 24% 6%	676
	11th to 20th	Day	12% 4 20% 33% 24% 7%	518
	21st to end	Day	12% 1 16% 31% 30% 9%	539
September	1st to 10th	Day	14% 3 14% 36% 27% 6%	490
	11th to 20th	Day	11% 2 20% 32% 24% 12%	490
	21st to end	Day	11% 9% 26% 30% 19% 5%	395
October	1st to 10th	Day	14% 11% 31% 29% 11% 4	300
	11th to 20th	Day	19% 17% 35% 21% 7% 1	300
	21st to end	Day	32% 17% 31% 18% 3	330
November	1st to 10th	Day	18% 13% 40% 21% 6% 2	297
	11th to 20th	Day	22% 19% 37% 15% 6% 1	270
	21st to end	Day	29% 17% 33% 16% 5%	270
December	1st to 10th	Day	17% 29% 31% 14% 7% 2	270
	11th to 20th	Day	22% 23% 37% 14% 3 1	270
	21st to end	Day	26% 27% 34% 10% 2	297
January	1st to 10th	Night	21% 21% 37% 18% 4	950
	11th to 20th	Night	22% 26% 32% 17% 3	950
	21st to end	Night	20% 21% 37% 21% 1	1045
February	1st to 10th	Night	22% 20% 38% 17% 2	950
	11th to 20th	Night	21% 19% 42% 17% 1	813
	21st to end	Night	25% 22% 35% 16% 2	628
March	1st to 10th	Night	24% 17% 38% 19% 2	660
	11th to 20th	Night	23% 14% 36% 23% 4	570
	21st to end	Night	26% 17% 34% 18% 4	627
April	1st to 10th	Night	14% 18% 41% 24% 4	570
	11th to 20th	Night	19% 17% 32% 26% 5% 1	563
	21st to end	Night	24% 12% 37% 20% 8%	570
May	1st to 10th	Night	18% 8% 36% 30% 8%	570
	11th to 20th	Night	18% 7% 31% 28% 15% 1	561
	21st to end	Night	12% 6% 29% 33% 17% 3	617
June	1st to 10th	Night	10% 5% 21% 35% 27% 2	570
	11th to 20th	Night	7% 2 25% 43% 22% 2	570
	21st to end	Night	4 2 27% 44% 21% 2	570
July	1st to 10th	Night	11% 1 14% 35% 32% 7%	555
	11th to 20th	Night	3 2 19% 40% 32% 3	552
	21st to end	Night	7% 1 18% 40% 31% 3	624
August	1st to 10th	Night	8% 2 17% 39% 34% 1	567
	11th to 20th	Night	8% 2 16% 41% 30% 2	564
	21st to end	Night	6% 2 17% 35% 35% 5%	627
September	1st to 10th	Night	14% 2 15% 37% 28% 4	570
	11th to 20th	Night	12% 2 14% 39% 26% 6%	570
	21st to end	Night	11% 6% 26% 31% 22% 4	712
October	1st to 10th	Night	9% 6% 28% 31% 24% 3	760
	11th to 20th	Night	17% 12% 35% 24% 11% 1	760
	21st to end	Night	24% 14% 32% 23% 6%	836
November	1st to 10th	Night	15% 11% 39% 27% 8%	779
	11th to 20th	Night	20% 16% 33% 23% 8%	760
	21st to end	Night	23% 16% 34% 21% 5%	874
December	1st to 10th	Night	23% 16% 36% 21% 4	950
	11th to 20th	Night	25% 14% 35% 22% 4	950
	21st to end	Night	26% 20% 35% 18% 2	1045

Page generated at 2024-11-07 05:55:47. Version ac07

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