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 2025-03-12.

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% 4 8% 5% 4 5% 4 6% 7% 36%	109096
	Night	12% 9% 4 9% 5% 4 4 3 5% 6% 38%	110142
Transparency	Day	46% 5% 12% 24% 11% 1	112729
	Night	46% 4 12% 23% 13% 1	114649
Seeing	Day	17% 10% 31% 27% 13% 3	16363
	Night	16% 9% 34% 30% 10% 1	26443

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	6% 14% 6% 20% 10% 7% 7% 4 5% 5% 16%	3617
	11th to 20th	Day	6% 12% 5% 12% 7% 7% 9% 8% 11% 7% 15%	3781
	21st to end	Day	7% 15% 8% 14% 7% 4 5% 3 5% 4 27%	4488
February	1st to 10th	Day	9% 11% 6% 12% 9% 6% 6% 5% 6% 6% 24%	1800
	11th to 20th	Day	9% 13% 4 9% 6% 6% 6% 5% 7% 6% 31%	1754
	21st to end	Day	12% 11% 3 10% 7% 5% 5% 4 6% 6% 31%	1546
March	1st to 10th	Day	14% 9% 3 7% 4 4 4 3 5% 7% 40%	3510
	11th to 20th	Day	11% 9% 3 8% 4 4 5% 3 6% 8% 39%	3491
	21st to end	Day	25% 13% 5% 10% 7% 4 4 3 4 5% 21%	3833
April	1st to 10th	Day	18% 11% 3 7% 5% 4 4 4 6% 6% 31%	2280
	11th to 20th	Day	19% 13% 4 6% 5% 3 4 3 5% 6% 32%	2258
	21st to end	Day	22% 12% 3 7% 5% 4 5% 3 5% 5% 29%	2470
May	1st to 10th	Day	17% 7% 2 6% 5% 4 5% 5% 7% 7% 35%	4178
	11th to 20th	Day	13% 7% 2 6% 4 4 4 4 6% 8% 43%	4399
	21st to end	Day	18% 7% 2 7% 4 4 5% 3 5% 7% 38%	4824
June	1st to 10th	Day	12% 5% 2 6% 4 3 4 4 5% 8% 47%	2660
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 7% 9% 40%	2660
	21st to end	Day	11% 6% 2 6% 4 5% 5% 4 7% 9% 41%	2660
July	1st to 10th	Day	10% 6% 3 7% 5% 5% 5% 5% 8% 10% 39%	4440
	11th to 20th	Day	5% 3 1 5% 3 4 4 3 6% 8% 57%	4440
	21st to end	Day	6% 4 2 5% 5% 5% 5% 5% 7% 10% 47%	4659
August	1st to 10th	Day	12% 7% 2 6% 4 4 4 3 6% 8% 44%	4104
	11th to 20th	Day	13% 6% 3 6% 4 4 5% 4 6% 10% 41%	4041
	21st to end	Day	8% 5% 3 6% 4 4 4 3 5% 7% 50%	4320
September	1st to 10th	Day	14% 5% 1 5% 3 4 4 3 5% 7% 48%	2280
	11th to 20th	Day	11% 6% 2 5% 4 3 4 3 5% 7% 49%	2233
	21st to end	Day	14% 6% 2 6% 5% 3 5% 4 5% 7% 45%	2009
October	1st to 10th	Day	15% 8% 3 6% 4 3 4 3 4 6% 45%	1900
	11th to 20th	Day	15% 9% 3 6% 4 3 4 3 4 5% 44%	1900
	21st to end	Day	19% 10% 4 6% 3 3 3 3 5% 6% 37%	2090
November	1st to 10th	Day	12% 10% 4 7% 4 3 4 4 5% 7% 40%	1671
	11th to 20th	Day	11% 14% 5% 11% 5% 4 5% 4 5% 5% 31%	1600
	21st to end	Day	13% 12% 5% 9% 5% 4 3 3 6% 7% 34%	1600
December	1st to 10th	Day	8% 8% 4 13% 11% 9% 7% 4 5% 7% 27%	2610
	11th to 20th	Day	11% 14% 6% 12% 9% 9% 5% 4 5% 5% 20%	3008
	21st to end	Day	18% 19% 8% 21% 5% 4 3 2 3 4 14%	3982
January	1st to 10th	Night	7% 11% 5% 19% 8% 8% 6% 4 5% 5% 22%	6348
	11th to 20th	Night	6% 10% 5% 12% 9% 7% 10% 7% 9% 5% 20%	6194
	21st to end	Night	9% 14% 7% 11% 6% 5% 4 3 5% 5% 31%	6490
February	1st to 10th	Night	8% 14% 5% 11% 6% 6% 5% 3 4 6% 32%	2600
	11th to 20th	Night	8% 11% 4 8% 6% 6% 5% 4 5% 7% 37%	2533
	21st to end	Night	12% 9% 4 9% 6% 5% 4 3 5% 6% 37%	2082
March	1st to 10th	Night	11% 8% 3 6% 4 3 4 3 5% 7% 47%	3591
	11th to 20th	Night	10% 7% 3 8% 4 4 4 4 6% 8% 42%	3497
	21st to end	Night	25% 13% 3 9% 4 3 3 3 3 5% 29%	3796
April	1st to 10th	Night	14% 12% 3 6% 5% 4 4 4 5% 7% 37%	1900
	11th to 20th	Night	20% 10% 4 7% 4 4 4 3 5% 5% 35%	1870
	21st to end	Night	19% 11% 3 7% 4 3 3 3 5% 6% 36%	1710
May	1st to 10th	Night	16% 7% 2 7% 4 4 4 3 4 6% 44%	2727
	11th to 20th	Night	13% 5% 2 5% 4 4 4 3 5% 7% 49%	2506
	21st to end	Night	14% 8% 3 6% 4 4 4 3 6% 7% 43%	2743
June	1st to 10th	Night	11% 4 2 5% 4 4 4 2 6% 8% 50%	1520
	11th to 20th	Night	11% 4 2 6% 5% 5% 4 4 6% 8% 44%	1520
	21st to end	Night	10% 5% 1 4 3 3 3 2 6% 8% 55%	1520
July	1st to 10th	Night	11% 5% 2 4 4 4 5% 4 7% 9% 45%	2530
	11th to 20th	Night	4 3 1 3 3 3 4 4 5% 8% 62%	2530
	21st to end	Night	5% 3 2 4 4 4 4 3 6% 9% 57%	2901
August	1st to 10th	Night	12% 6% 2 5% 4 3 4 3 4 7% 48%	2836
	11th to 20th	Night	13% 5% 2 4 3 3 4 3 6% 7% 52%	2798
	21st to end	Night	9% 4 2 6% 4 3 3 3 5% 7% 52%	3338
September	1st to 10th	Night	9% 4 1 5% 3 2 3 3 4 8% 57%	1900
	11th to 20th	Night	10% 5% 2 5% 3 3 3 3 6% 7% 53%	1943
	21st to end	Night	10% 6% 2 5% 4 3 3 3 4 7% 53%	2152
October	1st to 10th	Night	14% 6% 2 5% 3 3 3 3 4 6% 51%	2280
	11th to 20th	Night	15% 7% 2 5% 4 4 3 3 5% 8% 44%	2280
	21st to end	Night	17% 10% 3 6% 3 3 4 3 5% 7% 39%	2508
November	1st to 10th	Night	12% 9% 3 6% 3 4 3 4 5% 6% 45%	2624
	11th to 20th	Night	11% 12% 5% 10% 5% 4 4 3 4 5% 37%	2800
	21st to end	Night	13% 12% 4 8% 5% 4 4 3 4 6% 38%	2800
December	1st to 10th	Night	6% 9% 4 12% 9% 7% 5% 4 6% 7% 31%	4580
	11th to 20th	Night	11% 14% 7% 14% 7% 5% 5% 4 4 5% 25%	5199
	21st to end	Night	20% 15% 7% 18% 5% 4 3 3 4 4 15%	6996

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	69% 5% 8% 13% 5%	3618
	11th to 20th	Day	61% 3 9% 16% 12%	3781
	21st to end	Day	61% 4 13% 13% 8%	4488
February	1st to 10th	Day	59% 5% 12% 14% 9% 1	1800
	11th to 20th	Day	52% 6% 12% 22% 7% 1	1763
	21st to end	Day	53% 5% 12% 19% 11% 1	1546
March	1st to 10th	Day	43% 5% 12% 26% 12% 1	3510
	11th to 20th	Day	42% 4 11% 30% 11% 2	3491
	21st to end	Day	67% 4 9% 14% 5%	3833
April	1st to 10th	Day	52% 6% 11% 20% 10% 1	2280
	11th to 20th	Day	54% 5% 10% 19% 12% 1	2258
	21st to end	Day	57% 5% 11% 18% 8% 1	2470
May	1st to 10th	Day	44% 6% 13% 23% 12% 1	4216
	11th to 20th	Day	37% 7% 11% 30% 12% 2	4403
	21st to end	Day	45% 7% 12% 25% 11% 1	4837
June	1st to 10th	Day	35% 6% 14% 29% 14% 1	2660
	11th to 20th	Day	40% 7% 13% 22% 16% 1	2660
	21st to end	Day	38% 7% 16% 26% 11% 2	2660
July	1st to 10th	Day	40% 7% 20% 24% 9% 1	4371
	11th to 20th	Day	25% 5% 14% 35% 19% 2	4365
	21st to end	Day	30% 8% 15% 30% 15% 2	4512
August	1st to 10th	Day	39% 4 12% 30% 13% 2	4090
	11th to 20th	Day	40% 6% 15% 30% 10%	4080
	21st to end	Day	34% 5% 16% 29% 15% 1	4319
September	1st to 10th	Day	35% 6% 12% 31% 16%	2280
	11th to 20th	Day	35% 6% 15% 31% 13% 1	2233
	21st to end	Day	40% 5% 10% 30% 14% 1	2009
October	1st to 10th	Day	30% 4 6% 36% 23% 1	3160
	11th to 20th	Day	39% 4 12% 23% 22% 1	3140
	21st to end	Day	43% 3 13% 30% 10%	3428
November	1st to 10th	Day	44% 6% 14% 19% 15% 3	1671
	11th to 20th	Day	55% 5% 11% 19% 10% 1	1600
	21st to end	Day	49% 5% 17% 21% 8% 1	1600
December	1st to 10th	Day	58% 5% 15% 16% 6% 1	2610
	11th to 20th	Day	67% 4 14% 11% 4	3005
	21st to end	Day	76% 3 9% 9% 3	3982
January	1st to 10th	Night	64% 4 10% 16% 6%	6348
	11th to 20th	Night	60% 5% 10% 14% 11% 1	6194
	21st to end	Night	56% 3 12% 19% 10%	6490
February	1st to 10th	Night	54% 4 11% 21% 9% 2	2600
	11th to 20th	Night	47% 5% 13% 24% 10% 1	2534
	21st to end	Night	48% 4 12% 22% 12% 2	2082
March	1st to 10th	Night	37% 5% 11% 30% 15% 1	3591
	11th to 20th	Night	39% 4 9% 29% 17% 1	3497
	21st to end	Night	60% 4 8% 18% 8% 2	3796
April	1st to 10th	Night	47% 5% 11% 22% 14% 1	1900
	11th to 20th	Night	50% 5% 10% 16% 16% 3	1870
	21st to end	Night	49% 5% 8% 22% 14% 2	1710
May	1st to 10th	Night	41% 5% 11% 19% 22% 1	2754
	11th to 20th	Night	34% 6% 11% 26% 18% 5%	2507
	21st to end	Night	40% 7% 10% 27% 17% 1	2751
June	1st to 10th	Night	32% 7% 12% 31% 16% 2	1520
	11th to 20th	Night	37% 7% 13% 21% 19% 3	1520
	21st to end	Night	28% 5% 16% 30% 19% 3	1520
July	1st to 10th	Night	34% 5% 20% 27% 12% 1	2490
	11th to 20th	Night	22% 4 15% 37% 21% 2	2482
	21st to end	Night	24% 6% 17% 31% 20% 2	2809
August	1st to 10th	Night	37% 5% 11% 28% 16% 3	2826
	11th to 20th	Night	32% 6% 14% 31% 15% 1	2825
	21st to end	Night	31% 4 19% 26% 17% 2	3338
September	1st to 10th	Night	27% 4 13% 33% 22% 1	1900
	11th to 20th	Night	30% 6% 14% 31% 18% 1	1943
	21st to end	Night	33% 4 11% 31% 19% 1	2152
October	1st to 10th	Night	24% 3 6% 34% 29% 4	3800
	11th to 20th	Night	30% 4 13% 26% 23% 5%	3779
	21st to end	Night	43% 4 11% 28% 14% 1	4120
November	1st to 10th	Night	41% 4 14% 24% 15% 2	2624
	11th to 20th	Night	50% 6% 11% 19% 13% 1	2800
	21st to end	Night	49% 4 15% 23% 9% 1	2800
December	1st to 10th	Night	52% 4 17% 20% 7%	4580
	11th to 20th	Night	62% 4 12% 17% 5%	5201
	21st to end	Night	73% 4 8% 12% 4	6996

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% 14% 35% 25% 9% 3	300
	11th to 20th	Day	18% 12% 40% 25% 4 1	300
	21st to end	Day	14% 10% 42% 24% 8% 2	330
February	1st to 10th	Day	13% 15% 44% 24% 2 1	300
	11th to 20th	Day	15% 14% 39% 25% 6%	300
	21st to end	Day	22% 13% 39% 24% 3	249
March	1st to 10th	Day	16% 14% 44% 21% 5%	300
	11th to 20th	Day	23% 12% 33% 24% 7% 1	273
	21st to end	Day	31% 11% 28% 19% 9% 1	304
April	1st to 10th	Day	27% 14% 34% 20% 5%	460
	11th to 20th	Day	27% 16% 25% 23% 8% 1	456
	21st to end	Day	26% 13% 27% 22% 8% 3	650
May	1st to 10th	Day	21% 13% 34% 23% 8% 2	653
	11th to 20th	Day	20% 12% 28% 25% 11% 4	675
	21st to end	Day	20% 9% 27% 25% 16% 3	734
June	1st to 10th	Day	12% 7% 26% 33% 18% 5%	680
	11th to 20th	Day	14% 8% 33% 33% 10% 3	680
	21st to end	Day	13% 8% 30% 28% 16% 5%	680
July	1st to 10th	Day	6% 4 25% 32% 23% 9%	671
	11th to 20th	Day	7% 6% 29% 30% 20% 8%	668
	21st to end	Day	8% 2 23% 39% 21% 6%	739
August	1st to 10th	Day	11% 4 21% 33% 25% 5%	676
	11th to 20th	Day	14% 4 22% 31% 23% 6%	665
	21st to end	Day	11% 3 32% 32% 17% 6%	627
September	1st to 10th	Day	17% 6% 28% 30% 16% 4	490
	11th to 20th	Day	12% 6% 32% 29% 17% 3	443
	21st to end	Day	14% 14% 29% 26% 11% 5%	300
October	1st to 10th	Day	21% 10% 25% 26% 15% 4	300
	11th to 20th	Day	18% 15% 41% 19% 6%	300
	21st to end	Day	28% 17% 33% 15% 7%	330
November	1st to 10th	Day	17% 16% 35% 21% 9% 1	300
	11th to 20th	Day	20% 18% 42% 16% 4	300
	21st to end	Day	19% 15% 42% 21% 3	300
December	1st to 10th	Day	16% 11% 43% 23% 6% 1	300
	11th to 20th	Day	18% 15% 41% 20% 5% 1	300
	21st to end	Day	26% 15% 36% 18% 4	330
January	1st to 10th	Night	12% 12% 41% 28% 8%	1000
	11th to 20th	Night	17% 12% 38% 28% 5% 1	1000
	21st to end	Night	18% 12% 37% 27% 6%	1100
February	1st to 10th	Night	15% 13% 40% 27% 5% 1	1000
	11th to 20th	Night	14% 11% 45% 23% 5% 1	979
	21st to end	Night	17% 12% 36% 27% 7% 1	762
March	1st to 10th	Night	19% 10% 40% 23% 7% 1	640
	11th to 20th	Night	19% 10% 38% 26% 7%	575
	21st to end	Night	24% 9% 31% 24% 10% 1	627
April	1st to 10th	Night	19% 14% 37% 26% 4	570
	11th to 20th	Night	25% 12% 32% 25% 6% 1	563
	21st to end	Night	23% 10% 33% 26% 7% 2	570
May	1st to 10th	Night	20% 9% 32% 31% 7% 1	570
	11th to 20th	Night	18% 7% 31% 33% 10% 1	561
	21st to end	Night	17% 8% 29% 34% 12%	617
June	1st to 10th	Night	12% 4 31% 40% 13% 1	570
	11th to 20th	Night	12% 5% 34% 39% 10%	570
	21st to end	Night	11% 3 28% 41% 16% 1	570
July	1st to 10th	Night	7% 2 22% 41% 26% 2	555
	11th to 20th	Night	5% 3 27% 40% 24% 2	552
	21st to end	Night	5% 2 20% 51% 21% 2	624
August	1st to 10th	Night	10% 2 19% 45% 23% 2	567
	11th to 20th	Night	11% 2 20% 40% 23% 4	564
	21st to end	Night	8% 2 26% 40% 21% 3	627
September	1st to 10th	Night	12% 4 24% 41% 16% 3	570
	11th to 20th	Night	12% 5% 31% 33% 15% 2	570
	21st to end	Night	12% 9% 33% 31% 14% 1	632
October	1st to 10th	Night	17% 7% 32% 29% 14% 1	760
	11th to 20th	Night	18% 11% 37% 27% 6% 1	760
	21st to end	Night	24% 11% 32% 27% 6%	836
November	1st to 10th	Night	19% 11% 39% 24% 7% 1	882
	11th to 20th	Night	17% 13% 41% 23% 6%	1000
	21st to end	Night	18% 13% 42% 22% 6%	1000
December	1st to 10th	Night	16% 9% 41% 26% 7% 1	1000
	11th to 20th	Night	19% 9% 40% 25% 5% 1	1000
	21st to end	Night	25% 11% 33% 25% 5%	1100

Page generated at 2025-03-09 07:08:41. Version ac07

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