Kalamazoo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kalamazoo clear sky chart from 2005-11-06 to 2024-11-04.

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% 11% 4 8% 5% 5% 4 4 5% 7% 33%	101190
	Night	15% 12% 4 9% 5% 4 4 3 5% 6% 32%	97872
Transparency	Day	47% 7% 12% 20% 12% 1	104776
	Night	50% 6% 11% 19% 12% 1	102414
Seeing	Day	18% 15% 30% 22% 12% 4	15769
	Night	19% 12% 30% 27% 11% 1	25606

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	15% 22% 7% 12% 7% 5% 4 4 4 5% 15%	2527
	11th to 20th	Day	13% 21% 8% 14% 9% 13% 5% 2 3 4 8%	2530
	21st to end	Day	23% 23% 9% 14% 5% 4 2 2 3 4 9%	2787
February	1st to 10th	Day	14% 15% 7% 14% 11% 7% 4 3 4 5% 17%	1786
	11th to 20th	Day	14% 13% 6% 16% 9% 5% 4 3 4 4 21%	1848
	21st to end	Day	15% 16% 7% 14% 6% 4 4 3 4 4 22%	1570
March	1st to 10th	Day	15% 14% 5% 8% 6% 5% 4 3 5% 7% 28%	3120
	11th to 20th	Day	11% 9% 5% 11% 7% 5% 5% 4 6% 7% 31%	3399
	21st to end	Day	19% 13% 7% 10% 6% 5% 4 3 4 5% 24%	3939
April	1st to 10th	Day	17% 15% 4 7% 5% 4 4 4 6% 6% 29%	2280
	11th to 20th	Day	17% 11% 3 7% 4 4 4 4 4 7% 36%	2300
	21st to end	Day	17% 10% 3 7% 5% 5% 4 3 5% 7% 34%	2470
May	1st to 10th	Day	17% 8% 3 7% 5% 5% 5% 4 6% 7% 34%	4082
	11th to 20th	Day	14% 8% 3 7% 5% 5% 4 4 6% 8% 36%	4081
	21st to end	Day	11% 7% 2 6% 5% 4 5% 3 6% 8% 44%	4755
June	1st to 10th	Day	10% 6% 2 7% 5% 5% 4 4 6% 8% 43%	2660
	11th to 20th	Day	10% 5% 2 6% 4 5% 4 4 6% 9% 44%	2660
	21st to end	Day	10% 6% 3 6% 5% 4 6% 4 7% 9% 39%	2660
July	1st to 10th	Day	10% 7% 3 7% 5% 6% 5% 4 7% 9% 37%	4440
	11th to 20th	Day	8% 4 2 4 4 4 5% 4 7% 9% 50%	4440
	21st to end	Day	7% 5% 2 6% 5% 5% 5% 5% 7% 9% 44%	4796
August	1st to 10th	Day	12% 6% 2 5% 4 4 5% 4 6% 9% 43%	4104
	11th to 20th	Day	11% 6% 2 5% 4 4 5% 4 5% 7% 46%	4044
	21st to end	Day	8% 5% 2 6% 5% 4 5% 4 6% 9% 46%	4214
September	1st to 10th	Day	11% 6% 2 6% 5% 4 5% 4 5% 7% 44%	2242
	11th to 20th	Day	11% 5% 2 5% 4 4 4 3 6% 8% 48%	2090
	21st to end	Day	12% 8% 3 7% 4 5% 4 4 6% 8% 39%	2090
October	1st to 10th	Day	14% 7% 3 7% 4 4 5% 3 5% 6% 42%	2090
	11th to 20th	Day	19% 10% 3 8% 5% 5% 5% 4 5% 7% 29%	1870
	21st to end	Day	22% 12% 3 10% 5% 4 5% 3 5% 6% 25%	1881
November	1st to 10th	Day	12% 13% 4 7% 4 4 5% 4 5% 6% 37%	1699
	11th to 20th	Day	15% 18% 5% 11% 5% 4 4 4 5% 5% 23%	1710
	21st to end	Day	20% 17% 6% 11% 5% 3 3 3 5% 6% 21%	1710
December	1st to 10th	Day	15% 22% 10% 11% 6% 4 4 3 4 4 17%	1615
	11th to 20th	Day	13% 21% 9% 14% 6% 5% 4 3 5% 4 16%	1918
	21st to end	Day	21% 25% 8% 12% 7% 4 3 2 3 6% 9%	2783
January	1st to 10th	Night	16% 19% 9% 15% 6% 5% 4 3 3 4 15%	4428
	11th to 20th	Night	14% 20% 9% 17% 7% 8% 5% 3 4 4 10%	4440
	21st to end	Night	26% 17% 8% 16% 6% 4 4 2 3 3 10%	4880
February	1st to 10th	Night	14% 18% 6% 12% 10% 5% 4 3 4 5% 20%	2390
	11th to 20th	Night	14% 14% 6% 14% 8% 5% 3 3 4 5% 24%	2218
	21st to end	Night	18% 12% 5% 11% 7% 4 4 3 5% 5% 26%	1884
March	1st to 10th	Night	16% 10% 5% 8% 5% 4 4 3 4 6% 35%	3733
	11th to 20th	Night	10% 8% 3 7% 5% 4 4 3 5% 7% 43%	3560
	21st to end	Night	18% 12% 5% 12% 4 5% 4 3 5% 7% 27%	3708
April	1st to 10th	Night	15% 10% 4 7% 4 5% 4 3 5% 7% 35%	1900
	11th to 20th	Night	19% 10% 3 6% 5% 3 4 4 5% 6% 36%	1828
	21st to end	Night	17% 9% 3 6% 5% 4 3 4 5% 7% 37%	1710
May	1st to 10th	Night	15% 9% 3 8% 5% 5% 4 4 6% 8% 35%	2813
	11th to 20th	Night	18% 8% 3 6% 3 3 3 3 4 7% 42%	2812
	21st to end	Night	13% 6% 2 7% 5% 4 4 3 5% 8% 42%	2806
June	1st to 10th	Night	10% 6% 1 5% 3 3 4 3 7% 11% 47%	1520
	11th to 20th	Night	10% 5% 2 5% 4 5% 4 4 7% 10% 43%	1520
	21st to end	Night	9% 5% 1 6% 5% 4 5% 4 7% 9% 45%	1520
July	1st to 10th	Night	9% 4 2 5% 5% 5% 6% 4 6% 10% 43%	2530
	11th to 20th	Night	7% 3 2 5% 3 3 3 3 5% 8% 57%	2530
	21st to end	Night	6% 6% 2 5% 4 4 5% 4 7% 9% 47%	2766
August	1st to 10th	Night	10% 5% 2 5% 4 4 5% 4 6% 10% 46%	2825
	11th to 20th	Night	11% 5% 2 6% 4 4 4 4 5% 7% 48%	2785
	21st to end	Night	8% 6% 3 7% 4 4 5% 4 6% 7% 46%	3439
September	1st to 10th	Night	9% 6% 2 6% 4 3 4 3 6% 8% 49%	1919
	11th to 20th	Night	10% 6% 1 5% 3 4 3 3 4 7% 54%	2090
	21st to end	Night	13% 8% 3 7% 3 4 4 3 5% 6% 43%	2090
October	1st to 10th	Night	15% 7% 2 6% 4 3 4 3 4 6% 46%	2090
	11th to 20th	Night	17% 11% 3 8% 5% 4 3 3 4 6% 36%	2305
	21st to end	Night	24% 10% 2 6% 4 4 4 3 4 6% 32%	2717
November	1st to 10th	Night	14% 12% 3 7% 5% 4 4 3 4 5% 39%	2452
	11th to 20th	Night	15% 17% 4 10% 5% 4 5% 3 5% 7% 25%	2470
	21st to end	Night	18% 16% 5% 9% 5% 4 4 3 5% 6% 24%	2470
December	1st to 10th	Night	17% 23% 7% 11% 5% 5% 4 3 5% 5% 16%	2561
	11th to 20th	Night	15% 21% 8% 15% 5% 5% 3 3 4 4 17%	3279
	21st to end	Night	26% 22% 7% 10% 5% 4 4 3 4 4 11%	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	69% 8% 11% 10% 2	2528
	11th to 20th	Day	79% 8% 7% 4 1	2530
	21st to end	Day	79% 5% 7% 7% 2	2787
February	1st to 10th	Day	70% 5% 9% 10% 5% 1	1786
	11th to 20th	Day	66% 5% 9% 13% 7%	1858
	21st to end	Day	64% 6% 12% 12% 5% 1	1570
March	1st to 10th	Day	55% 7% 12% 20% 7%	3120
	11th to 20th	Day	49% 8% 14% 21% 7% 1	3399
	21st to end	Day	61% 7% 9% 16% 6% 1	3939
April	1st to 10th	Day	54% 6% 10% 19% 11%	2280
	11th to 20th	Day	47% 6% 10% 21% 13% 2	2300
	21st to end	Day	48% 6% 13% 16% 14% 2	2470
May	1st to 10th	Day	45% 9% 13% 21% 13%	4120
	11th to 20th	Day	41% 9% 15% 23% 11% 1	4085
	21st to end	Day	35% 8% 12% 20% 24% 2	4768
June	1st to 10th	Day	36% 7% 12% 26% 17% 2	2660
	11th to 20th	Day	35% 7% 14% 24% 19% 2	2660
	21st to end	Day	38% 10% 14% 20% 15% 2	2660
July	1st to 10th	Day	42% 6% 14% 20% 15% 3	4371
	11th to 20th	Day	28% 7% 15% 31% 17% 2	4365
	21st to end	Day	34% 9% 16% 19% 20% 2	4645
August	1st to 10th	Day	36% 7% 15% 25% 16% 1	4091
	11th to 20th	Day	35% 7% 12% 30% 15% 1	4083
	21st to end	Day	34% 7% 13% 28% 16% 2	4213
September	1st to 10th	Day	38% 6% 14% 23% 15% 3	2242
	11th to 20th	Day	33% 6% 12% 30% 18% 1	2090
	21st to end	Day	41% 7% 12% 23% 16% 1	2090
October	1st to 10th	Day	30% 4 9% 38% 18% 1	3480
	11th to 20th	Day	41% 5% 11% 24% 18%	3073
	21st to end	Day	49% 4 11% 24% 10% 1	3081
November	1st to 10th	Day	47% 7% 12% 21% 12% 1	1699
	11th to 20th	Day	62% 6% 10% 15% 6% 1	1710
	21st to end	Day	65% 5% 13% 13% 4	1710
December	1st to 10th	Day	70% 5% 10% 11% 3	1615
	11th to 20th	Day	69% 8% 10% 11% 2	1915
	21st to end	Day	77% 6% 8% 7% 2	2783
January	1st to 10th	Night	71% 7% 9% 9% 4	4428
	11th to 20th	Night	77% 7% 7% 5% 3	4440
	21st to end	Night	79% 6% 8% 5% 2	4880
February	1st to 10th	Night	66% 6% 9% 12% 6% 1	2390
	11th to 20th	Night	62% 5% 10% 16% 7%	2219
	21st to end	Night	60% 5% 13% 14% 6% 2	1884
March	1st to 10th	Night	50% 6% 12% 25% 7% 1	3733
	11th to 20th	Night	38% 9% 14% 24% 15% 2	3560
	21st to end	Night	56% 8% 12% 16% 8% 1	3708
April	1st to 10th	Night	47% 7% 11% 21% 13% 1	1900
	11th to 20th	Night	48% 5% 9% 17% 18% 3	1828
	21st to end	Night	45% 7% 12% 18% 16% 2	1710
May	1st to 10th	Night	45% 7% 12% 22% 12% 1	2840
	11th to 20th	Night	42% 6% 10% 23% 17% 2	2813
	21st to end	Night	38% 9% 11% 20% 20% 2	2814
June	1st to 10th	Night	31% 6% 13% 30% 17% 2	1520
	11th to 20th	Night	33% 9% 13% 24% 19% 2	1520
	21st to end	Night	33% 9% 15% 23% 17% 2	1520
July	1st to 10th	Night	35% 6% 14% 24% 13% 7%	2490
	11th to 20th	Night	26% 7% 13% 28% 24% 2	2482
	21st to end	Night	32% 7% 16% 17% 25% 3	2678
August	1st to 10th	Night	32% 7% 15% 30% 15% 1	2814
	11th to 20th	Night	34% 6% 12% 31% 16% 1	2812
	21st to end	Night	36% 6% 10% 29% 17% 2	3439
September	1st to 10th	Night	31% 7% 13% 26% 19% 3	1919
	11th to 20th	Night	30% 5% 9% 32% 22% 1	2090
	21st to end	Night	41% 6% 10% 25% 16% 1	2090
October	1st to 10th	Night	27% 4 10% 34% 24% 1	3480
	11th to 20th	Night	41% 4 10% 23% 21%	3828
	21st to end	Night	42% 4 9% 28% 16% 1	4467
November	1st to 10th	Night	47% 6% 10% 22% 13% 1	2452
	11th to 20th	Night	58% 6% 12% 15% 7% 1	2470
	21st to end	Night	60% 6% 13% 17% 3	2470
December	1st to 10th	Night	71% 6% 9% 11% 5%	2561
	11th to 20th	Night	70% 6% 10% 10% 3	3281
	21st to end	Night	75% 6% 10% 6% 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	23% 21% 33% 18% 5% 1	270
	11th to 20th	Day	25% 21% 40% 10% 4	270
	21st to end	Day	25% 21% 34% 18% 2	297
February	1st to 10th	Day	26% 24% 30% 15% 3 1	270
	11th to 20th	Day	26% 24% 35% 14% 1	270
	21st to end	Day	25% 35% 29% 9% 1	225
March	1st to 10th	Day	21% 29% 36% 10% 3	270
	11th to 20th	Day	20% 21% 34% 19% 6%	405
	21st to end	Day	29% 20% 31% 16% 4 1	506
April	1st to 10th	Day	26% 18% 32% 18% 4	460
	11th to 20th	Day	27% 24% 26% 15% 7% 2	452
	21st to end	Day	25% 19% 31% 17% 7% 1	460
May	1st to 10th	Day	22% 20% 30% 19% 7% 2	463
	11th to 20th	Day	20% 13% 31% 23% 10% 5%	487
	21st to end	Day	14% 12% 29% 26% 15% 4	691
June	1st to 10th	Day	13% 11% 33% 28% 11% 4	680
	11th to 20th	Day	13% 10% 32% 29% 13% 3	680
	21st to end	Day	12% 14% 33% 27% 11% 3	680
July	1st to 10th	Day	8% 7% 27% 30% 20% 9%	671
	11th to 20th	Day	11% 7% 30% 27% 18% 7%	668
	21st to end	Day	8% 5% 28% 31% 21% 6%	734
August	1st to 10th	Day	10% 6% 22% 26% 22% 14%	486
	11th to 20th	Day	11% 5% 27% 26% 23% 8%	479
	21st to end	Day	11% 5% 24% 30% 22% 7%	539
September	1st to 10th	Day	13% 9% 25% 27% 20% 7%	490
	11th to 20th	Day	8% 7% 21% 26% 30% 8%	490
	21st to end	Day	16% 15% 22% 25% 16% 6%	490
October	1st to 10th	Day	18% 12% 27% 24% 14% 4	490
	11th to 20th	Day	23% 19% 28% 24% 6%	410
	21st to end	Day	29% 21% 34% 13% 3	330
November	1st to 10th	Day	18% 21% 33% 22% 5% 1	279
	11th to 20th	Day	25% 26% 28% 16% 4	270
	21st to end	Day	30% 19% 39% 11% 2	270
December	1st to 10th	Day	25% 34% 22% 14% 4	270
	11th to 20th	Day	21% 27% 36% 14% 2	270
	21st to end	Day	22% 31% 34% 11% 2	297
January	1st to 10th	Night	23% 17% 33% 21% 5%	950
	11th to 20th	Night	25% 16% 35% 21% 3 1	950
	21st to end	Night	22% 13% 37% 25% 3	1041
February	1st to 10th	Night	24% 15% 37% 20% 4	760
	11th to 20th	Night	20% 18% 34% 24% 3	743
	21st to end	Night	24% 19% 37% 17% 3	628
March	1st to 10th	Night	21% 16% 33% 23% 6%	760
	11th to 20th	Night	17% 15% 39% 23% 6%	760
	21st to end	Night	24% 14% 31% 25% 6%	778
April	1st to 10th	Night	17% 16% 34% 26% 5% 1	570
	11th to 20th	Night	24% 13% 35% 23% 4 1	563
	21st to end	Night	21% 12% 36% 24% 6% 1	570
May	1st to 10th	Night	19% 9% 35% 28% 7% 1	570
	11th to 20th	Night	22% 8% 28% 32% 10%	561
	21st to end	Night	15% 5% 31% 32% 16% 1	617
June	1st to 10th	Night	11% 5% 30% 39% 14%	570
	11th to 20th	Night	13% 5% 28% 39% 14% 1	570
	21st to end	Night	11% 5% 25% 39% 19% 2	570
July	1st to 10th	Night	8% 3 21% 37% 26% 4	555
	11th to 20th	Night	9% 3 21% 40% 23% 4	552
	21st to end	Night	7% 3 18% 44% 27% 1	624
August	1st to 10th	Night	9% 3 15% 43% 26% 3	567
	11th to 20th	Night	9% 2 17% 41% 27% 4	564
	21st to end	Night	9% 3 19% 36% 29% 3	627
September	1st to 10th	Night	10% 4 21% 36% 24% 4	589
	11th to 20th	Night	11% 4 19% 36% 27% 4	760
	21st to end	Night	17% 9% 23% 29% 18% 4	760
October	1st to 10th	Night	17% 8% 25% 30% 18% 1	760
	11th to 20th	Night	22% 14% 30% 26% 7% 1	760
	21st to end	Night	28% 14% 31% 20% 6%	836
November	1st to 10th	Night	21% 14% 30% 25% 9%	755
	11th to 20th	Night	23% 19% 33% 20% 4 1	760
	21st to end	Night	25% 13% 36% 23% 3	760
December	1st to 10th	Night	27% 18% 34% 18% 4	851
	11th to 20th	Night	25% 16% 38% 18% 3	950
	21st to end	Night	32% 18% 34% 15% 1	1045

Page generated at 2024-11-01 22:47:47. Version ac07

Copyright © 2024 Attilla Danko.