Lee & Rose Warner Nature Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lee & Rose Warner Nature Center clear sky chart from 2005-11-06 to 2025-01-07.

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% 9% 3 8% 5% 4 4 4 5% 7% 37%	105252
	Night	12% 10% 4 9% 5% 4 4 3 5% 6% 38%	103912
Transparency	Day	46% 4 13% 25% 11% 1	108845
	Night	47% 4 12% 24% 12% 1	108459
Seeing	Day	16% 10% 30% 26% 14% 4	16228
	Night	16% 9% 31% 32% 11% 1	26208

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	10% 18% 7% 17% 5% 4 4 3 4 5% 23%	2575
	11th to 20th	Day	6% 11% 6% 14% 9% 8% 8% 7% 5% 5% 21%	2530
	21st to end	Day	9% 19% 7% 14% 6% 4 4 3 5% 6% 24%	3103
February	1st to 10th	Day	8% 12% 5% 10% 7% 6% 5% 5% 6% 6% 31%	1710
	11th to 20th	Day	8% 12% 5% 10% 6% 5% 4 4 5% 6% 36%	1664
	21st to end	Day	10% 12% 5% 11% 5% 5% 5% 4 4 7% 32%	1486
March	1st to 10th	Day	12% 10% 4 7% 5% 5% 4 4 4 7% 40%	3312
	11th to 20th	Day	11% 8% 3 8% 5% 5% 4 3 5% 8% 39%	3480
	21st to end	Day	22% 13% 4 11% 5% 5% 4 3 4 6% 23%	3895
April	1st to 10th	Day	16% 11% 3 7% 5% 4 4 3 5% 7% 34%	2280
	11th to 20th	Day	20% 12% 4 7% 4 4 4 3 4 5% 32%	2254
	21st to end	Day	21% 12% 3 6% 5% 5% 4 4 4 6% 31%	2460
May	1st to 10th	Day	18% 7% 2 6% 4 4 4 3 5% 7% 41%	4305
	11th to 20th	Day	14% 6% 2 6% 4 4 4 3 5% 7% 45%	4399
	21st to end	Day	17% 8% 3 7% 4 5% 4 4 6% 7% 36%	4824
June	1st to 10th	Day	12% 5% 2 4 3 4 5% 4 7% 8% 45%	2660
	11th to 20th	Day	12% 7% 3 6% 5% 5% 5% 5% 6% 8% 37%	2660
	21st to end	Day	11% 5% 2 6% 5% 5% 5% 5% 7% 9% 41%	2660
July	1st to 10th	Day	11% 6% 2 6% 4 5% 5% 5% 8% 10% 38%	4440
	11th to 20th	Day	6% 2 1 4 3 3 3 3 5% 8% 60%	4440
	21st to end	Day	8% 4 2 5% 4 4 5% 4 6% 9% 48%	4813
August	1st to 10th	Day	12% 5% 2 6% 4 5% 5% 4 6% 9% 43%	4114
	11th to 20th	Day	13% 5% 2 5% 4 3 4 4 7% 7% 45%	4041
	21st to end	Day	11% 5% 2 7% 4 4 4 3 6% 7% 46%	4308
September	1st to 10th	Day	11% 6% 2 5% 3 4 4 4 5% 8% 47%	2280
	11th to 20th	Day	12% 6% 2 5% 4 5% 4 5% 6% 7% 45%	2280
	21st to end	Day	14% 6% 2 6% 4 4 4 4 6% 7% 43%	1981
October	1st to 10th	Day	17% 7% 2 5% 3 4 4 3 5% 6% 44%	1900
	11th to 20th	Day	14% 11% 3 7% 4 5% 5% 3 5% 6% 38%	1900
	21st to end	Day	17% 12% 4 8% 4 3 3 3 4 6% 37%	2038
November	1st to 10th	Day	12% 13% 4 8% 5% 5% 4 3 5% 5% 36%	1660
	11th to 20th	Day	12% 15% 7% 10% 7% 4 4 3 6% 5% 28%	1600
	21st to end	Day	14% 12% 4 8% 6% 4 4 4 5% 7% 33%	1600
December	1st to 10th	Day	7% 11% 4 15% 12% 8% 6% 4 6% 5% 22%	2610
	11th to 20th	Day	10% 17% 7% 11% 6% 4 4 3 4 5% 28%	3008
	21st to end	Day	19% 20% 8% 19% 5% 3 3 2 3 3 14%	3982
January	1st to 10th	Night	10% 15% 9% 13% 6% 4 4 3 5% 5% 27%	4513
	11th to 20th	Night	8% 11% 5% 14% 7% 7% 9% 7% 7% 5% 21%	4440
	21st to end	Night	12% 18% 7% 12% 6% 5% 4 3 4 4 25%	4561
February	1st to 10th	Night	5% 11% 5% 10% 7% 6% 5% 3 5% 6% 35%	2470
	11th to 20th	Night	6% 10% 4 9% 5% 7% 4 4 5% 8% 38%	2403
	21st to end	Night	12% 11% 4 9% 5% 6% 4 4 4 6% 36%	1966
March	1st to 10th	Night	9% 8% 3 7% 4 4 4 3 5% 8% 46%	3555
	11th to 20th	Night	9% 8% 3 8% 5% 5% 5% 4 6% 6% 41%	3480
	21st to end	Night	25% 11% 3 11% 5% 3 3 2 3 4 29%	3736
April	1st to 10th	Night	17% 12% 2 7% 4 4 3 4 6% 6% 36%	1900
	11th to 20th	Night	21% 10% 3 7% 4 4 4 3 4 5% 35%	1875
	21st to end	Night	19% 9% 3 6% 5% 4 4 3 5% 6% 34%	1718
May	1st to 10th	Night	14% 8% 3 8% 4 4 4 4 5% 5% 42%	2600
	11th to 20th	Night	14% 4 2 4 3 3 4 3 5% 7% 51%	2506
	21st to end	Night	13% 7% 3 7% 4 3 4 3 6% 7% 41%	2743
June	1st to 10th	Night	11% 5% 2 4 4 4 4 5% 6% 8% 47%	1520
	11th to 20th	Night	8% 5% 2 6% 4 4 6% 3 7% 7% 47%	1520
	21st to end	Night	7% 5% 1 5% 4 4 4 4 6% 8% 52%	1520
July	1st to 10th	Night	12% 5% 1 4 3 3 4 4 7% 9% 48%	2530
	11th to 20th	Night	3 3 2 4 3 4 4 4 6% 9% 59%	2530
	21st to end	Night	5% 3 1 4 3 4 4 3 6% 8% 59%	2750
August	1st to 10th	Night	13% 5% 2 6% 4 4 4 3 6% 6% 47%	2823
	11th to 20th	Night	13% 4 2 4 4 3 4 3 6% 9% 48%	2798
	21st to end	Night	10% 6% 3 7% 4 4 4 3 6% 7% 46%	3350
September	1st to 10th	Night	9% 4 1 6% 3 4 3 4 5% 8% 54%	1900
	11th to 20th	Night	9% 5% 1 4 3 4 3 3 5% 7% 54%	1900
	21st to end	Night	14% 5% 2 3 4 3 4 3 4 7% 51%	2176
October	1st to 10th	Night	14% 6% 2 5% 3 3 3 3 4 6% 49%	2280
	11th to 20th	Night	17% 9% 2 5% 4 4 4 3 5% 6% 41%	2280
	21st to end	Night	18% 11% 3 7% 3 3 3 4 5% 6% 37%	2558
November	1st to 10th	Night	14% 10% 3 6% 4 4 4 3 5% 6% 40%	2636
	11th to 20th	Night	13% 11% 4 11% 6% 4 4 3 5% 5% 33%	2800
	21st to end	Night	14% 9% 4 9% 5% 4 4 3 5% 7% 35%	2800
December	1st to 10th	Night	6% 10% 4 15% 7% 8% 5% 3 5% 7% 29%	4580
	11th to 20th	Night	11% 17% 6% 15% 6% 4 5% 4 5% 4 24%	5199
	21st to end	Night	21% 15% 8% 16% 5% 3 4 2 3 4 17%	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	65% 3 10% 17% 4	2576
	11th to 20th	Day	65% 4 10% 15% 6%	2530
	21st to end	Day	62% 4 14% 15% 4	3103
February	1st to 10th	Day	52% 4 14% 20% 9% 1	1710
	11th to 20th	Day	50% 4 12% 24% 9% 1	1673
	21st to end	Day	52% 5% 11% 21% 10% 1	1486
March	1st to 10th	Day	46% 3 15% 24% 12% 1	3312
	11th to 20th	Day	44% 4 10% 33% 8% 1	3480
	21st to end	Day	64% 3 9% 18% 5%	3895
April	1st to 10th	Day	50% 4 11% 22% 12% 1	2280
	11th to 20th	Day	55% 3 9% 19% 12% 2	2254
	21st to end	Day	55% 4 12% 20% 9%	2460
May	1st to 10th	Day	44% 4 11% 27% 14% 2	4344
	11th to 20th	Day	39% 3 12% 29% 14% 2	4403
	21st to end	Day	48% 4 11% 26% 11% 1	4837
June	1st to 10th	Day	34% 5% 16% 31% 12% 1	2660
	11th to 20th	Day	43% 6% 13% 24% 13% 1	2660
	21st to end	Day	38% 5% 16% 29% 9% 2	2660
July	1st to 10th	Day	38% 7% 18% 25% 11% 1	4371
	11th to 20th	Day	22% 5% 17% 36% 19% 1	4365
	21st to end	Day	31% 6% 15% 30% 17% 1	4662
August	1st to 10th	Day	38% 5% 13% 29% 13% 1	4099
	11th to 20th	Day	36% 5% 13% 36% 10%	4080
	21st to end	Day	37% 4 18% 27% 13% 1	4307
September	1st to 10th	Day	35% 5% 13% 34% 13%	2280
	11th to 20th	Day	37% 5% 18% 32% 8%	2280
	21st to end	Day	40% 4 11% 33% 11%	1981
October	1st to 10th	Day	30% 3 9% 38% 21%	3160
	11th to 20th	Day	40% 4 12% 27% 16% 1	3140
	21st to end	Day	45% 2 16% 28% 9%	3340
November	1st to 10th	Day	50% 4 13% 19% 12% 2	1660
	11th to 20th	Day	58% 4 13% 17% 8% 1	1600
	21st to end	Day	51% 4 17% 20% 6% 2	1600
December	1st to 10th	Day	64% 5% 13% 14% 4	2610
	11th to 20th	Day	60% 2 12% 19% 6%	3005
	21st to end	Day	78% 2 7% 9% 4	3982
January	1st to 10th	Night	61% 3 11% 19% 6% 1	4513
	11th to 20th	Night	62% 4 13% 15% 6%	4440
	21st to end	Night	64% 2 10% 19% 5% 1	4561
February	1st to 10th	Night	50% 4 11% 24% 9% 1	2470
	11th to 20th	Night	46% 4 14% 27% 8% 2	2404
	21st to end	Night	50% 4 11% 22% 11% 1	1966
March	1st to 10th	Night	39% 3 14% 26% 17% 1	3555
	11th to 20th	Night	43% 3 9% 28% 15% 1	3480
	21st to end	Night	61% 3 8% 20% 8% 1	3736
April	1st to 10th	Night	49% 4 8% 23% 15% 1	1900
	11th to 20th	Night	52% 3 7% 21% 15% 2	1875
	21st to end	Night	49% 5% 9% 21% 14% 2	1718
May	1st to 10th	Night	44% 4 11% 20% 20% 1	2626
	11th to 20th	Night	33% 4 9% 29% 20% 4	2507
	21st to end	Night	42% 4 13% 24% 16% 1	2751
June	1st to 10th	Night	33% 5% 14% 30% 17% 2	1520
	11th to 20th	Night	35% 5% 15% 25% 18% 3	1520
	21st to end	Night	30% 4 16% 32% 15% 3	1520
July	1st to 10th	Night	33% 5% 21% 26% 14% 1	2490
	11th to 20th	Night	20% 6% 14% 38% 20% 2	2482
	21st to end	Night	23% 5% 16% 33% 21% 3	2662
August	1st to 10th	Night	36% 5% 12% 29% 14% 3	2814
	11th to 20th	Night	34% 5% 15% 32% 13% 1	2825
	21st to end	Night	37% 6% 16% 28% 11% 2	3350
September	1st to 10th	Night	30% 5% 14% 35% 16% 1	1900
	11th to 20th	Night	30% 4 17% 34% 16%	1900
	21st to end	Night	34% 3 14% 34% 14% 1	2176
October	1st to 10th	Night	25% 2 6% 37% 26% 4	3800
	11th to 20th	Night	36% 3 12% 25% 22% 2	3779
	21st to end	Night	46% 3 11% 27% 12%	4206
November	1st to 10th	Night	45% 4 12% 24% 14% 1	2636
	11th to 20th	Night	54% 4 12% 19% 11% 1	2800
	21st to end	Night	50% 4 16% 22% 7% 1	2800
December	1st to 10th	Night	57% 5% 15% 19% 4	4580
	11th to 20th	Night	64% 3 10% 16% 5% 1	5201
	21st to end	Night	73% 2 9% 13% 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% 13% 34% 26% 10% 2	288
	11th to 20th	Day	18% 10% 41% 25% 6%	270
	21st to end	Day	16% 8% 39% 25% 11% 2	297
February	1st to 10th	Day	16% 14% 46% 18% 5% 1	270
	11th to 20th	Day	14% 17% 43% 18% 6% 1	270
	21st to end	Day	17% 14% 38% 28% 3	225
March	1st to 10th	Day	18% 12% 44% 17% 9% 1	270
	11th to 20th	Day	16% 11% 40% 23% 8% 2	270
	21st to end	Day	24% 14% 29% 21% 8% 3	340
April	1st to 10th	Day	22% 14% 34% 23% 5% 1	460
	11th to 20th	Day	30% 12% 24% 25% 9% 1	452
	21st to end	Day	26% 12% 29% 20% 11% 2	640
May	1st to 10th	Day	22% 12% 30% 25% 9% 2	653
	11th to 20th	Day	20% 12% 27% 25% 13% 3	675
	21st to end	Day	18% 9% 26% 27% 16% 4	734
June	1st to 10th	Day	11% 7% 29% 32% 18% 4	680
	11th to 20th	Day	15% 8% 34% 30% 11% 3	680
	21st to end	Day	14% 8% 29% 28% 16% 6%	680
July	1st to 10th	Day	8% 4 21% 32% 24% 10%	671
	11th to 20th	Day	9% 6% 26% 30% 21% 9%	668
	21st to end	Day	7% 4 25% 35% 21% 8%	739
August	1st to 10th	Day	10% 5% 22% 34% 24% 5%	676
	11th to 20th	Day	14% 4 19% 31% 26% 6%	665
	21st to end	Day	12% 6% 24% 34% 20% 5%	615
September	1st to 10th	Day	14% 7% 28% 29% 17% 6%	490
	11th to 20th	Day	12% 5% 28% 31% 20% 3	490
	21st to end	Day	16% 13% 29% 22% 14% 6%	300
October	1st to 10th	Day	18% 12% 26% 26% 14% 4	300
	11th to 20th	Day	19% 19% 33% 21% 7% 1	300
	21st to end	Day	23% 12% 38% 20% 5% 1	330
November	1st to 10th	Day	19% 14% 34% 23% 9% 1	300
	11th to 20th	Day	20% 19% 38% 19% 4	300
	21st to end	Day	24% 12% 41% 18% 5%	300
December	1st to 10th	Day	16% 10% 44% 21% 8% 1	300
	11th to 20th	Day	21% 14% 38% 21% 5%	300
	21st to end	Day	28% 14% 36% 17% 3 1	330
January	1st to 10th	Night	13% 12% 35% 32% 8% 1	981
	11th to 20th	Night	17% 10% 35% 30% 7% 1	950
	21st to end	Night	18% 11% 33% 30% 7% 1	1045
February	1st to 10th	Night	12% 11% 39% 29% 7% 1	950
	11th to 20th	Night	12% 12% 40% 29% 6% 1	929
	21st to end	Night	18% 12% 32% 30% 7%	710
March	1st to 10th	Night	16% 11% 38% 27% 8% 1	660
	11th to 20th	Night	18% 9% 38% 29% 6%	570
	21st to end	Night	23% 10% 29% 26% 10% 2	627
April	1st to 10th	Night	23% 11% 32% 26% 6%	570
	11th to 20th	Night	26% 8% 32% 26% 7%	563
	21st to end	Night	24% 9% 29% 29% 8% 1	570
May	1st to 10th	Night	22% 8% 32% 31% 7% 1	570
	11th to 20th	Night	18% 6% 31% 33% 11% 1	561
	21st to end	Night	12% 7% 26% 39% 15% 1	617
June	1st to 10th	Night	13% 4 28% 42% 12% 1	570
	11th to 20th	Night	10% 5% 31% 44% 10% 1	570
	21st to end	Night	10% 3 24% 45% 15% 2	570
July	1st to 10th	Night	6% 2 20% 41% 28% 2	555
	11th to 20th	Night	7% 4 22% 43% 22% 2	552
	21st to end	Night	6% 2 21% 46% 23% 2	624
August	1st to 10th	Night	9% 2 16% 50% 21% 2	567
	11th to 20th	Night	15% 3 18% 35% 27% 3	564
	21st to end	Night	9% 4 24% 37% 23% 2	627
September	1st to 10th	Night	11% 5% 22% 41% 18% 3	570
	11th to 20th	Night	11% 6% 26% 37% 19% 2	570
	21st to end	Night	16% 7% 29% 31% 15% 2	660
October	1st to 10th	Night	18% 8% 29% 32% 13% 1	760
	11th to 20th	Night	22% 10% 31% 29% 7% 1	760
	21st to end	Night	25% 9% 29% 30% 7%	836
November	1st to 10th	Night	20% 10% 33% 30% 7% 1	880
	11th to 20th	Night	19% 13% 34% 27% 7%	1000
	21st to end	Night	18% 15% 35% 25% 7%	1000
December	1st to 10th	Night	16% 10% 36% 30% 7% 1	1000
	11th to 20th	Night	20% 10% 37% 26% 7% 1	1000
	21st to end	Night	25% 10% 32% 26% 6%	1100

Page generated at 2025-01-04 02:24:01. Version ac07

Copyright © 2025 Attilla Danko.