Waseca
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Waseca clear sky chart from 2005-11-06 to 2026-07-16.

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% 9% 3 8% 5% 4 5% 4 6% 7% 38%	138640
	Night	12% 9% 4 9% 5% 5% 4 4 5% 6% 38%	134405
Transparency	Day	45% 5% 12% 25% 12% 1	142232
	Night	46% 4 12% 24% 13% 2	138892
Seeing	Day	17% 10% 31% 27% 12% 3	18326
	Night	16% 9% 34% 30% 10% 1	28182

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	7% 15% 6% 21% 10% 7% 6% 4 5% 6% 16%	4691
	11th to 20th	Day	5% 12% 6% 13% 8% 8% 9% 7% 10% 7% 16%	4927
	21st to end	Day	5% 12% 7% 12% 7% 6% 8% 5% 6% 6% 27%	5812
February	1st to 10th	Day	8% 12% 6% 12% 9% 6% 6% 5% 6% 6% 23%	1890
	11th to 20th	Day	9% 12% 4 10% 6% 6% 6% 5% 7% 6% 31%	1844
	21st to end	Day	12% 11% 3 10% 7% 5% 4 4 6% 6% 31%	1621
March	1st to 10th	Day	13% 7% 3 7% 4 3 4 3 5% 7% 44%	4996
	11th to 20th	Day	11% 9% 3 6% 3 3 4 3 6% 8% 43%	5090
	21st to end	Day	23% 11% 4 9% 6% 4 4 3 4 6% 25%	5616
April	1st to 10th	Day	18% 12% 3 8% 5% 4 4 3 6% 5% 32%	2520
	11th to 20th	Day	18% 13% 4 7% 5% 4 4 3 5% 6% 32%	2498
	21st to end	Day	21% 12% 3 7% 4 4 5% 3 5% 5% 30%	2730
May	1st to 10th	Day	10% 6% 2 5% 4 4 5% 4 6% 7% 47%	7795
	11th to 20th	Day	16% 7% 2 5% 3 3 3 3 5% 7% 46%	8222
	21st to end	Day	18% 7% 3 7% 4 4 5% 3 5% 7% 37%	9047
June	1st to 10th	Day	11% 5% 2 6% 4 4 4 4 5% 8% 46%	2940
	11th to 20th	Day	13% 6% 2 7% 4 5% 4 4 7% 8% 39%	2940
	21st to end	Day	11% 6% 2 6% 4 4 5% 4 7% 9% 41%	2940
July	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 7% 10% 44%	6500
	11th to 20th	Day	8% 4 1 5% 3 4 3 3 6% 8% 56%	6431
	21st to end	Day	8% 4 2 6% 4 4 5% 4 7% 9% 46%	6700
August	1st to 10th	Day	12% 7% 2 6% 4 4 4 3 6% 8% 44%	4234
	11th to 20th	Day	13% 6% 3 6% 4 4 5% 4 6% 10% 40%	4171
	21st to end	Day	8% 5% 2 6% 4 4 4 4 6% 7% 49%	4456
September	1st to 10th	Day	14% 5% 2 5% 3 3 4 3 5% 8% 47%	2400
	11th to 20th	Day	11% 5% 2 5% 4 4 4 3 5% 7% 48%	2350
	21st to end	Day	13% 6% 2 6% 5% 3 4 3 5% 7% 46%	2115
October	1st to 10th	Day	15% 8% 3 6% 4 3 4 3 4 6% 45%	2000
	11th to 20th	Day	16% 9% 3 6% 3 3 4 4 4 6% 43%	2000
	21st to end	Day	19% 10% 4 6% 3 3 3 3 5% 6% 37%	2200
November	1st to 10th	Day	12% 10% 4 7% 4 3 4 4 5% 7% 40%	1756
	11th to 20th	Day	11% 15% 5% 11% 5% 4 4 4 5% 5% 32%	1680
	21st to end	Day	13% 11% 5% 10% 5% 4 3 3 6% 7% 34%	1680
December	1st to 10th	Day	7% 9% 4 13% 11% 9% 7% 4 5% 7% 27%	2690
	11th to 20th	Day	11% 14% 6% 12% 9% 8% 5% 4 5% 5% 20%	3088
	21st to end	Day	18% 19% 8% 21% 5% 4 3 2 3 4 14%	4070
January	1st to 10th	Night	8% 12% 5% 17% 8% 8% 5% 4 5% 5% 23%	8232
	11th to 20th	Night	5% 11% 4 13% 9% 7% 10% 8% 8% 5% 20%	8058
	21st to end	Night	7% 11% 6% 10% 6% 6% 6% 4 6% 6% 33%	8402
February	1st to 10th	Night	8% 14% 5% 11% 6% 6% 5% 3 5% 6% 31%	2730
	11th to 20th	Night	8% 11% 4 8% 6% 6% 5% 4 5% 6% 38%	2663
	21st to end	Night	12% 9% 4 9% 7% 5% 4 3 5% 6% 37%	2183
March	1st to 10th	Night	11% 8% 2 6% 4 3 3 3 5% 6% 48%	5119
	11th to 20th	Night	10% 7% 3 7% 4 4 4 4 6% 9% 43%	5090
	21st to end	Night	24% 12% 4 9% 4 3 3 3 4 5% 30%	5553
April	1st to 10th	Night	14% 12% 3 6% 5% 4 4 4 4 6% 37%	2100
	11th to 20th	Night	20% 9% 4 7% 4 4 4 3 5% 5% 36%	2069
	21st to end	Night	19% 11% 3 7% 4 3 3 3 5% 6% 36%	1890
May	1st to 10th	Night	10% 6% 2 5% 3 3 4 3 5% 6% 52%	5088
	11th to 20th	Night	15% 6% 2 4 3 4 3 3 5% 6% 49%	4670
	21st to end	Night	19% 8% 3 7% 4 4 4 3 5% 7% 37%	5139
June	1st to 10th	Night	11% 4 2 5% 4 4 4 2 6% 8% 50%	1680
	11th to 20th	Night	12% 5% 2 7% 5% 5% 5% 4 6% 7% 43%	1680
	21st to end	Night	10% 6% 1 4 3 3 4 3 6% 8% 53%	1680
July	1st to 10th	Night	8% 4 2 4 3 4 5% 4 8% 9% 48%	3698
	11th to 20th	Night	7% 5% 2 3 3 3 4 4 5% 8% 56%	3657
	21st to end	Night	9% 4 2 5% 4 4 4 3 5% 9% 51%	4168
August	1st to 10th	Night	12% 6% 2 5% 4 3 4 4 4 7% 48%	2926
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 6% 7% 52%	2888
	21st to end	Night	9% 4 2 6% 4 3 3 3 5% 7% 52%	3444
September	1st to 10th	Night	9% 4 1 5% 3 3 3 3 4 8% 56%	2000
	11th to 20th	Night	10% 5% 2 5% 3 3 4 3 6% 7% 52%	2046
	21st to end	Night	10% 6% 2 5% 4 3 3 3 4 7% 54%	2265
October	1st to 10th	Night	13% 6% 2 5% 3 3 3 3 4 6% 51%	2400
	11th to 20th	Night	16% 7% 2 6% 4 4 3 3 5% 7% 43%	2400
	21st to end	Night	18% 10% 3 6% 3 3 4 3 5% 7% 39%	2640
November	1st to 10th	Night	12% 10% 3 6% 3 4 3 4 5% 6% 44%	2758
	11th to 20th	Night	11% 12% 5% 10% 5% 4 4 3 4 5% 37%	2940
	21st to end	Night	13% 12% 4 9% 5% 4 4 3 4 6% 37%	2940
December	1st to 10th	Night	6% 9% 4 13% 9% 7% 5% 4 6% 7% 31%	4720
	11th to 20th	Night	11% 13% 7% 14% 7% 5% 5% 4 4 5% 25%	5339
	21st to end	Night	20% 15% 7% 18% 5% 4 3 3 4 4 15%	7150

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	70% 4 9% 12% 5%	4692
	11th to 20th	Day	62% 3 8% 17% 11%	4927
	21st to end	Day	58% 3 12% 20% 7%	5812
February	1st to 10th	Day	60% 4 12% 15% 9% 1	1890
	11th to 20th	Day	52% 5% 12% 23% 7% 1	1853
	21st to end	Day	52% 5% 13% 19% 10% 1	1621
March	1st to 10th	Day	40% 4 15% 27% 11% 2	4996
	11th to 20th	Day	40% 3 14% 29% 12% 2	5090
	21st to end	Day	62% 4 11% 17% 6%	5618
April	1st to 10th	Day	52% 5% 11% 21% 10% 1	2520
	11th to 20th	Day	54% 5% 11% 18% 11% 1	2498
	21st to end	Day	56% 5% 10% 19% 9% 1	2730
May	1st to 10th	Day	34% 5% 10% 32% 19%	7833
	11th to 20th	Day	38% 4 8% 29% 17% 4	8226
	21st to end	Day	46% 5% 10% 28% 10% 1	9061
June	1st to 10th	Day	36% 6% 14% 30% 14% 1	2940
	11th to 20th	Day	41% 7% 14% 22% 16% 1	2940
	21st to end	Day	39% 7% 16% 26% 11% 2	2940
July	1st to 10th	Day	36% 5% 17% 33% 9%	6431
	11th to 20th	Day	28% 4 14% 36% 17% 1	6356
	21st to end	Day	33% 7% 15% 31% 13% 1	6509
August	1st to 10th	Day	40% 4 12% 30% 12% 2	4220
	11th to 20th	Day	40% 6% 15% 30% 10%	4210
	21st to end	Day	34% 5% 16% 29% 15% 1	4455
September	1st to 10th	Day	36% 6% 13% 30% 15%	2400
	11th to 20th	Day	36% 5% 16% 31% 12% 1	2350
	21st to end	Day	39% 5% 10% 31% 15% 1	2115
October	1st to 10th	Day	30% 4 6% 37% 23% 1	3260
	11th to 20th	Day	39% 4 11% 23% 22% 1	3240
	21st to end	Day	43% 3 13% 30% 10%	3538
November	1st to 10th	Day	44% 5% 14% 19% 15% 3	1756
	11th to 20th	Day	54% 5% 11% 19% 10% 1	1680
	21st to end	Day	50% 5% 16% 21% 7% 1	1680
December	1st to 10th	Day	58% 5% 15% 16% 6% 1	2690
	11th to 20th	Day	66% 4 14% 12% 4	3085
	21st to end	Day	76% 3 9% 9% 3	4070
January	1st to 10th	Night	63% 3 13% 16% 5%	8233
	11th to 20th	Night	62% 4 9% 15% 9%	8058
	21st to end	Night	51% 3 11% 24% 10%	8402
February	1st to 10th	Night	54% 4 11% 21% 9% 1	2730
	11th to 20th	Night	47% 5% 12% 25% 10% 1	2664
	21st to end	Night	49% 4 11% 22% 12% 2	2183
March	1st to 10th	Night	37% 4 10% 31% 15% 2	5119
	11th to 20th	Night	38% 4 12% 29% 16% 1	5090
	21st to end	Night	58% 4 10% 16% 10% 2	5553
April	1st to 10th	Night	48% 5% 11% 21% 14% 1	2100
	11th to 20th	Night	49% 4 10% 18% 15% 3	2069
	21st to end	Night	49% 4 8% 22% 14% 2	1890
May	1st to 10th	Night	33% 4 9% 31% 21% 2	5115
	11th to 20th	Night	36% 4 8% 22% 23% 6%	4671
	21st to end	Night	47% 5% 8% 27% 12% 1	5149
June	1st to 10th	Night	32% 6% 13% 32% 16% 2	1680
	11th to 20th	Night	38% 7% 12% 21% 19% 3	1680
	21st to end	Night	30% 5% 16% 29% 18% 2	1680
July	1st to 10th	Night	30% 5% 20% 30% 13% 1	3660
	11th to 20th	Night	27% 4 15% 35% 16% 2	3612
	21st to end	Night	31% 5% 16% 30% 16% 2	4048
August	1st to 10th	Night	37% 5% 12% 28% 16% 3	2916
	11th to 20th	Night	33% 6% 14% 31% 15% 1	2915
	21st to end	Night	31% 4 18% 27% 17% 2	3444
September	1st to 10th	Night	29% 4 13% 32% 21% 1	2000
	11th to 20th	Night	31% 6% 15% 30% 17% 1	2046
	21st to end	Night	32% 4 11% 31% 20% 2	2265
October	1st to 10th	Night	24% 3 6% 33% 29% 4	3920
	11th to 20th	Night	30% 4 13% 26% 23% 4	3899
	21st to end	Night	43% 4 11% 28% 14% 1	4252
November	1st to 10th	Night	41% 4 14% 24% 14% 2	2758
	11th to 20th	Night	50% 6% 11% 19% 13% 1	2940
	21st to end	Night	50% 4 14% 23% 9% 1	2940
December	1st to 10th	Night	53% 4 17% 19% 7%	4720
	11th to 20th	Night	62% 3 12% 17% 5% 1	5341
	21st to end	Night	73% 4 8% 11% 4	7150

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	14% 13% 36% 26% 8% 3	330
	11th to 20th	Day	17% 12% 42% 24% 4 1	330
	21st to end	Day	13% 11% 42% 24% 9% 1	363
February	1st to 10th	Day	13% 16% 43% 25% 2 2	330
	11th to 20th	Day	15% 13% 39% 26% 7% 1	330
	21st to end	Day	21% 13% 38% 23% 4	273
March	1st to 10th	Day	16% 14% 43% 22% 5%	330
	11th to 20th	Day	25% 13% 32% 23% 5% 1	330
	21st to end	Day	29% 13% 31% 18% 7% 1	371
April	1st to 10th	Day	26% 15% 34% 20% 4	540
	11th to 20th	Day	26% 17% 26% 22% 7% 1	536
	21st to end	Day	26% 13% 30% 21% 7% 3	750
May	1st to 10th	Day	19% 13% 32% 24% 10% 2	753
	11th to 20th	Day	21% 12% 27% 26% 11% 3	775
	21st to end	Day	21% 8% 27% 27% 15% 2	844
June	1st to 10th	Day	12% 7% 26% 32% 18% 5%	780
	11th to 20th	Day	15% 9% 33% 31% 10% 3	780
	21st to end	Day	13% 8% 32% 27% 14% 4	780
July	1st to 10th	Day	7% 4 23% 34% 23% 9%	771
	11th to 20th	Day	7% 6% 28% 31% 20% 8%	744
	21st to end	Day	8% 2 23% 40% 21% 5%	794
August	1st to 10th	Day	11% 4 21% 33% 25% 6%	726
	11th to 20th	Day	14% 4 23% 30% 23% 6%	715
	21st to end	Day	11% 3 31% 31% 18% 6%	675
September	1st to 10th	Day	16% 6% 28% 28% 15% 5%	530
	11th to 20th	Day	12% 6% 31% 31% 17% 3	480
	21st to end	Day	13% 13% 27% 27% 13% 7%	330
October	1st to 10th	Day	19% 10% 27% 26% 14% 5%	330
	11th to 20th	Day	19% 16% 41% 18% 6%	330
	21st to end	Day	27% 17% 32% 16% 7%	363
November	1st to 10th	Day	18% 18% 36% 20% 8% 1	330
	11th to 20th	Day	20% 18% 42% 17% 3	330
	21st to end	Day	19% 16% 41% 21% 3	330
December	1st to 10th	Day	16% 11% 43% 23% 6% 1	330
	11th to 20th	Day	18% 16% 40% 20% 5% 1	330
	21st to end	Day	26% 15% 37% 17% 4	363
January	1st to 10th	Night	12% 11% 40% 28% 8%	1050
	11th to 20th	Night	16% 12% 38% 28% 5%	1050
	21st to end	Night	17% 12% 37% 28% 6%	1155
February	1st to 10th	Night	14% 13% 40% 27% 4 1	1050
	11th to 20th	Night	14% 11% 46% 23% 5% 1	1029
	21st to end	Night	16% 13% 37% 26% 7% 1	799
March	1st to 10th	Night	19% 11% 39% 23% 7% 1	672
	11th to 20th	Night	19% 10% 39% 25% 7%	630
	21st to end	Night	24% 10% 33% 23% 9% 1	693
April	1st to 10th	Night	19% 14% 37% 26% 4	630
	11th to 20th	Night	24% 12% 31% 26% 7% 1	623
	21st to end	Night	23% 10% 33% 25% 7% 1	630
May	1st to 10th	Night	19% 9% 32% 32% 8% 1	630
	11th to 20th	Night	19% 8% 30% 33% 10%	621
	21st to end	Night	18% 7% 28% 35% 11%	683
June	1st to 10th	Night	11% 4 31% 40% 13%	630
	11th to 20th	Night	13% 6% 34% 37% 10%	630
	21st to end	Night	11% 4 29% 40% 15% 1	630
July	1st to 10th	Night	7% 2 21% 41% 26% 2	615
	11th to 20th	Night	5% 3 25% 41% 24% 2	597
	21st to end	Night	6% 2 20% 50% 20% 2	657
August	1st to 10th	Night	9% 2 18% 45% 23% 2	597
	11th to 20th	Night	12% 3 20% 40% 23% 3	594
	21st to end	Night	8% 2 25% 40% 22% 3	660
September	1st to 10th	Night	12% 5% 25% 40% 15% 3	600
	11th to 20th	Night	12% 6% 31% 35% 15% 2	600
	21st to end	Night	12% 8% 32% 32% 15% 1	665
October	1st to 10th	Night	17% 7% 33% 30% 13% 1	800
	11th to 20th	Night	18% 11% 37% 27% 6% 1	800
	21st to end	Night	24% 11% 32% 27% 6%	880
November	1st to 10th	Night	18% 11% 39% 24% 7% 1	927
	11th to 20th	Night	17% 13% 41% 23% 5%	1050
	21st to end	Night	18% 13% 42% 21% 6%	1050
December	1st to 10th	Night	16% 9% 41% 26% 6% 1	1050
	11th to 20th	Night	19% 10% 40% 25% 5% 1	1050
	21st to end	Night	25% 12% 34% 25% 5%	1155

Page generated at 2026-07-13 02:14:53. Version ac07

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