Minden
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Minden clear sky chart from 2005-11-06 to 2024-10-24.

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% 7% 2 6% 4 4 4 4 5% 7% 43%	100865
	Night	13% 6% 2 5% 4 3 4 3 5% 7% 48%	97964
Transparency	Day	41% 3 10% 22% 19% 5%	100672
	Night	37% 3 10% 22% 21% 7%	97828
Seeing	Day	15% 8% 22% 26% 21% 7%	15117
	Night	15% 8% 25% 31% 18% 3	24875

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	20% 12% 3 5% 3 2 3 2 3 5% 42%	2847
	11th to 20th	Day	24% 6% 2 4 2 2 3 2 4 6% 45%	2850
	21st to end	Day	24% 7% 2 4 3 3 3 2 3 4 45%	3135
February	1st to 10th	Day	21% 10% 3 6% 4 3 3 3 3 5% 39%	1710
	11th to 20th	Day	21% 9% 2 6% 4 3 4 3 3 5% 40%	1792
	21st to end	Day	24% 8% 3 6% 4 3 3 2 4 4 37%	1727
March	1st to 10th	Day	20% 12% 4 9% 4 3 3 3 4 6% 33%	3436
	11th to 20th	Day	19% 8% 3 6% 4 4 5% 4 5% 6% 36%	3480
	21st to end	Day	16% 9% 2 8% 4 4 3 3 4 5% 41%	3814
April	1st to 10th	Day	14% 6% 3 6% 5% 4 4 3 5% 6% 43%	2213
	11th to 20th	Day	16% 8% 3 7% 4 4 4 4 4 7% 40%	2254
	21st to end	Day	12% 7% 3 5% 4 5% 5% 4 5% 6% 44%	2280
May	1st to 10th	Day	16% 8% 3 7% 5% 4 5% 4 6% 7% 34%	3765
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 3 6% 7% 44%	3985
	21st to end	Day	12% 7% 2 8% 5% 6% 5% 5% 6% 9% 35%	4477
June	1st to 10th	Day	7% 6% 2 6% 5% 6% 6% 6% 8% 10% 38%	2470
	11th to 20th	Day	7% 4 2 4 5% 5% 6% 6% 8% 10% 43%	2470
	21st to end	Day	5% 4 2 5% 4 6% 5% 6% 8% 10% 44%	2470
July	1st to 10th	Day	9% 6% 2 6% 5% 5% 6% 6% 9% 12% 35%	4120
	11th to 20th	Day	7% 4 2 6% 5% 5% 6% 6% 8% 10% 40%	4120
	21st to end	Day	16% 9% 3 7% 5% 5% 5% 4 6% 9% 31%	4465
August	1st to 10th	Day	3 2 1 3 3 3 3 3 5% 8% 67%	4104
	11th to 20th	Day	4 3 2 5% 3 4 5% 4 7% 11% 51%	3738
	21st to end	Day	7% 5% 2 7% 5% 5% 5% 5% 7% 8% 43%	4180
September	1st to 10th	Day	8% 4 2 6% 6% 6% 6% 4 6% 8% 46%	2280
	11th to 20th	Day	12% 6% 2 5% 5% 5% 5% 4 7% 8% 40%	2185
	21st to end	Day	7% 4 2 5% 4 4 4 4 5% 7% 55%	2024
October	1st to 10th	Day	7% 4 1 5% 3 3 4 3 5% 6% 60%	1900
	11th to 20th	Day	12% 7% 1 4 3 2 3 2 4 5% 56%	1900
	21st to end	Day	16% 5% 2 5% 3 3 2 3 3 5% 52%	2010
November	1st to 10th	Day	11% 5% 3 5% 4 4 4 3 4 6% 52%	1858
	11th to 20th	Day	11% 7% 2 6% 4 3 4 3 4 4 53%	1900
	21st to end	Day	19% 6% 2 6% 4 4 4 3 4 5% 44%	1900
December	1st to 10th	Day	16% 9% 2 7% 3 4 4 2 5% 5% 43%	1710
	11th to 20th	Day	17% 9% 3 5% 4 4 4 3 5% 5% 42%	2161
	21st to end	Day	17% 9% 3 7% 4 4 4 3 4 6% 41%	3135
January	1st to 10th	Night	17% 7% 2 6% 4 3 3 3 4 5% 47%	4108
	11th to 20th	Night	21% 5% 2 4 3 2 3 2 3 3 52%	4120
	21st to end	Night	24% 9% 2 5% 3 3 2 2 2 4 44%	4532
February	1st to 10th	Night	17% 9% 3 4 3 3 3 3 5% 5% 45%	2470
	11th to 20th	Night	21% 8% 2 6% 3 3 3 3 4 5% 44%	2282
	21st to end	Night	20% 9% 3 5% 4 3 2 3 3 5% 44%	1732
March	1st to 10th	Night	21% 9% 2 6% 4 4 3 3 4 6% 38%	3419
	11th to 20th	Night	17% 8% 2 5% 4 4 5% 3 6% 7% 39%	3480
	21st to end	Night	13% 7% 2 6% 5% 5% 4 4 6% 6% 43%	3817
April	1st to 10th	Night	12% 5% 2 4 4 4 4 4 6% 7% 48%	1967
	11th to 20th	Night	13% 6% 2 6% 5% 4 3 3 5% 7% 46%	1875
	21st to end	Night	11% 6% 2 5% 4 4 3 3 5% 8% 52%	1900
May	1st to 10th	Night	14% 7% 3 6% 4 5% 4 3 6% 8% 39%	3130
	11th to 20th	Night	15% 6% 3 6% 4 3 3 4 6% 8% 43%	2900
	21st to end	Night	11% 6% 3 5% 4 5% 4 4 5% 8% 43%	3090
June	1st to 10th	Night	5% 4 2 5% 4 4 4 4 8% 11% 50%	1710
	11th to 20th	Night	5% 3 1 3 4 3 4 3 7% 10% 55%	1710
	21st to end	Night	6% 3 2 5% 4 4 3 4 6% 8% 54%	1710
July	1st to 10th	Night	7% 5% 2 6% 4 5% 6% 6% 8% 12% 41%	2850
	11th to 20th	Night	5% 3 2 5% 4 4 5% 5% 9% 12% 47%	2850
	21st to end	Night	13% 9% 2 6% 4 4 4 4 5% 9% 40%	3098
August	1st to 10th	Night	2 1 2 2 2 2 3 5% 9% 71%	2836
	11th to 20th	Night	3 2 1 3 3 3 5% 4 8% 11% 57%	3091
	21st to end	Night	5% 4 2 6% 4 5% 5% 4 7% 9% 49%	3476
September	1st to 10th	Night	6% 4 2 6% 5% 5% 4 3 6% 8% 50%	1900
	11th to 20th	Night	9% 5% 3 6% 4 4 4 4 6% 7% 48%	1990
	21st to end	Night	8% 4 1 4 3 3 3 3 5% 6% 59%	2135
October	1st to 10th	Night	7% 3 1 3 3 3 4 3 5% 7% 61%	2280
	11th to 20th	Night	10% 4 2 4 3 3 3 2 4 5% 59%	2280
	21st to end	Night	14% 5% 2 4 3 3 3 2 3 4 58%	2413
November	1st to 10th	Night	11% 5% 1 4 3 3 3 2 3 6% 58%	2220
	11th to 20th	Night	11% 6% 2 5% 3 3 3 2 5% 6% 55%	2280
	21st to end	Night	15% 8% 3 6% 4 3 3 2 4 5% 48%	2280
December	1st to 10th	Night	18% 7% 2 5% 3 3 3 3 5% 6% 45%	2465
	11th to 20th	Night	15% 7% 2 5% 4 4 4 3 4 4 47%	3036
	21st to end	Night	17% 8% 2 6% 3 3 3 3 4 5% 47%	4532

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	48% 1 3 17% 27% 5%	2848
	11th to 20th	Day	43% 1 5% 23% 22% 4	2850
	21st to end	Day	45% 1 2 19% 21% 11%	3135
February	1st to 10th	Day	50% 2 7% 16% 16% 10%	1710
	11th to 20th	Day	49% 2 5% 17% 20% 7%	1801
	21st to end	Day	52% 2 5% 10% 21% 9%	1727
March	1st to 10th	Day	57% 1 5% 14% 18% 6%	3436
	11th to 20th	Day	49% 2 5% 22% 16% 5%	3480
	21st to end	Day	47% 2 6% 19% 24% 2	3814
April	1st to 10th	Day	42% 3 7% 23% 17% 8%	2213
	11th to 20th	Day	46% 2 8% 17% 19% 8%	2254
	21st to end	Day	41% 2 8% 22% 23% 4	2280
May	1st to 10th	Day	50% 2 8% 26% 11% 3	3800
	11th to 20th	Day	40% 2 9% 24% 23% 1	3989
	21st to end	Day	46% 3 13% 26% 11% 2	4489
June	1st to 10th	Day	39% 5% 14% 25% 15% 1	2470
	11th to 20th	Day	33% 6% 14% 27% 17% 3	2470
	21st to end	Day	33% 6% 14% 26% 17% 3	2470
July	1st to 10th	Day	39% 10% 20% 25% 6% 1	4056
	11th to 20th	Day	36% 6% 16% 29% 12% 1	4051
	21st to end	Day	49% 5% 14% 22% 10% 1	4325
August	1st to 10th	Day	17% 3 15% 31% 28% 6%	4090
	11th to 20th	Day	26% 5% 20% 34% 13% 1	3774
	21st to end	Day	37% 6% 13% 22% 21% 2	4179
September	1st to 10th	Day	35% 5% 13% 19% 19% 9%	2280
	11th to 20th	Day	41% 5% 10% 19% 19% 6%	2185
	21st to end	Day	29% 5% 7% 23% 25% 10%	2024
October	1st to 10th	Day	26% 3 8% 23% 24% 17%	1900
	11th to 20th	Day	32% 2 4 19% 27% 16%	1900
	21st to end	Day	37% 2 4 17% 29% 12%	2010
November	1st to 10th	Day	34% 3 7% 19% 26% 10%	1858
	11th to 20th	Day	36% 2 4 18% 28% 12%	1900
	21st to end	Day	45% 2 5% 17% 23% 8%	1900
December	1st to 10th	Day	45% 2 8% 19% 18% 8%	1710
	11th to 20th	Day	46% 2 4 14% 28% 6%	2159
	21st to end	Day	47% 1 5% 15% 26% 6%	3135
January	1st to 10th	Night	41% 2 4 16% 30% 7%	4108
	11th to 20th	Night	40% 1 5% 21% 25% 8%	4120
	21st to end	Night	49% 1 5% 16% 20% 9%	4532
February	1st to 10th	Night	43% 2 6% 19% 20% 10%	2470
	11th to 20th	Night	45% 2 5% 17% 21% 9%	2283
	21st to end	Night	46% 2 6% 16% 16% 15%	1732
March	1st to 10th	Night	50% 2 6% 16% 18% 8%	3419
	11th to 20th	Night	46% 2 9% 17% 20% 6%	3480
	21st to end	Night	42% 2 9% 18% 25% 3	3817
April	1st to 10th	Night	35% 4 10% 22% 18% 11%	1967
	11th to 20th	Night	39% 3 8% 18% 20% 12%	1875
	21st to end	Night	33% 3 8% 26% 26% 4	1900
May	1st to 10th	Night	44% 2 10% 24% 14% 5%	3160
	11th to 20th	Night	41% 2 11% 23% 21% 2	2901
	21st to end	Night	40% 3 15% 25% 15% 1	3099
June	1st to 10th	Night	28% 6% 15% 30% 19% 2	1710
	11th to 20th	Night	25% 5% 15% 30% 21% 4	1710
	21st to end	Night	27% 5% 16% 26% 23% 3	1710
July	1st to 10th	Night	35% 7% 24% 27% 6% 1	2805
	11th to 20th	Night	27% 6% 20% 32% 13% 2	2796
	21st to end	Night	42% 5% 17% 26% 9% 1	2999
August	1st to 10th	Night	12% 3 17% 31% 31% 5%	2826
	11th to 20th	Night	19% 6% 20% 38% 15% 2	3121
	21st to end	Night	31% 6% 14% 25% 23% 2	3476
September	1st to 10th	Night	32% 5% 14% 19% 18% 11%	1900
	11th to 20th	Night	35% 4 11% 21% 20% 9%	1990
	21st to end	Night	26% 3 9% 22% 26% 12%	2135
October	1st to 10th	Night	24% 3 8% 23% 24% 19%	2280
	11th to 20th	Night	29% 2 5% 15% 30% 19%	2280
	21st to end	Night	32% 2 5% 18% 26% 17%	2413
November	1st to 10th	Night	30% 2 8% 19% 27% 14%	2220
	11th to 20th	Night	33% 2 7% 18% 27% 13%	2280
	21st to end	Night	42% 2 4 19% 24% 10%	2280
December	1st to 10th	Night	41% 2 9% 19% 21% 8%	2465
	11th to 20th	Night	43% 2 5% 13% 25% 11%	3037
	21st to end	Night	43% 2 4 19% 26% 6%	4532

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	23% 19% 41% 12% 5%	270
	11th to 20th	Day	31% 16% 36% 14% 3 1	270
	21st to end	Day	26% 24% 31% 18% 2	297
February	1st to 10th	Day	29% 18% 34% 13% 5% 1	270
	11th to 20th	Day	32% 20% 35% 11% 1	270
	21st to end	Day	37% 24% 32% 5% 2	225
March	1st to 10th	Day	30% 16% 35% 16% 3	270
	11th to 20th	Day	23% 23% 38% 15% 1	270
	21st to end	Day	23% 18% 40% 16% 2 1	297
April	1st to 10th	Day	24% 15% 37% 18% 6% 1	393
	11th to 20th	Day	26% 12% 29% 23% 8% 1	452
	21st to end	Day	20% 10% 30% 28% 8% 2	460
May	1st to 10th	Day	17% 10% 36% 26% 9% 2	463
	11th to 20th	Day	15% 5% 27% 30% 20% 4	617
	21st to end	Day	10% 6% 25% 36% 18% 5%	734
June	1st to 10th	Day	10% 3 16% 34% 27% 11%	680
	11th to 20th	Day	5% 3 16% 39% 30% 6%	680
	21st to end	Day	6% 4 14% 31% 34% 12%	680
July	1st to 10th	Day	9% 2 10% 32% 35% 12%	671
	11th to 20th	Day	5% 2 7% 31% 37% 17%	668
	21st to end	Day	7% 2 6% 34% 38% 12%	739
August	1st to 10th	Day	6% 1 8% 26% 45% 14%	676
	11th to 20th	Day	7% 1 3 27% 48% 13%	488
	21st to end	Day	13% 2 6% 21% 37% 21%	539
September	1st to 10th	Day	8% 1 9% 28% 36% 17%	490
	11th to 20th	Day	11% 2 13% 30% 30% 15%	395
	21st to end	Day	9% 4 10% 37% 29% 10%	300
October	1st to 10th	Day	8% 2 21% 43% 20% 7%	300
	11th to 20th	Day	12% 7% 34% 29% 14% 4	300
	21st to end	Day	24% 9% 31% 22% 12% 2	306
November	1st to 10th	Day	16% 8% 31% 29% 14% 2	270
	11th to 20th	Day	14% 10% 43% 23% 8%	270
	21st to end	Day	26% 11% 34% 20% 8% 1	270
December	1st to 10th	Day	19% 12% 42% 18% 6% 3	270
	11th to 20th	Day	24% 14% 36% 21% 4	270
	21st to end	Day	26% 16% 38% 13% 4 2	297
January	1st to 10th	Night	23% 13% 32% 27% 6%	950
	11th to 20th	Night	25% 13% 30% 24% 8%	950
	21st to end	Night	23% 12% 35% 26% 3	1045
February	1st to 10th	Night	22% 13% 34% 26% 4	950
	11th to 20th	Night	26% 13% 36% 22% 3	807
	21st to end	Night	26% 17% 35% 19% 2	476
March	1st to 10th	Night	21% 11% 33% 30% 5%	570
	11th to 20th	Night	20% 11% 37% 26% 4 1	570
	21st to end	Night	16% 12% 39% 27% 6%	627
April	1st to 10th	Night	15% 11% 41% 26% 7%	570
	11th to 20th	Night	17% 12% 35% 24% 11% 1	563
	21st to end	Night	14% 9% 36% 30% 10% 1	570
May	1st to 10th	Night	12% 8% 35% 33% 11% 1	570
	11th to 20th	Night	13% 5% 29% 34% 17% 3	561
	21st to end	Night	6% 4 24% 39% 23% 4	617
June	1st to 10th	Night	6% 1 13% 44% 33% 3	570
	11th to 20th	Night	6% 2 13% 40% 37% 3	570
	21st to end	Night	5% 1 13% 37% 34% 9%	570
July	1st to 10th	Night	4 2 7% 34% 46% 8%	555
	11th to 20th	Night	4 1 5% 38% 41% 10%	552
	21st to end	Night	5% 2 7% 35% 42% 9%	624
August	1st to 10th	Night	3 1 4 36% 45% 10%	567
	11th to 20th	Night	5% 1 6% 35% 45% 8%	564
	21st to end	Night	9% 1 6% 30% 42% 10%	627
September	1st to 10th	Night	8% 1 9% 35% 40% 7%	570
	11th to 20th	Night	12% 2 12% 30% 39% 6%	570
	21st to end	Night	8% 3 11% 39% 33% 6%	615
October	1st to 10th	Night	9% 3 13% 41% 29% 5%	760
	11th to 20th	Night	12% 6% 24% 37% 20% 2	760
	21st to end	Night	17% 6% 28% 31% 16% 2	805
November	1st to 10th	Night	13% 5% 26% 36% 18% 2	740
	11th to 20th	Night	13% 9% 28% 38% 11% 1	760
	21st to end	Night	19% 10% 29% 30% 11% 1	760
December	1st to 10th	Night	23% 9% 31% 29% 8%	945
	11th to 20th	Night	24% 11% 31% 29% 6%	950
	21st to end	Night	23% 13% 30% 28% 6%	1045

Page generated at 2024-10-21 01:20:00. Version ac07

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