Leamington
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Leamington clear sky chart from 2005-11-06 to 2024-01-22.

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	14% 8% 4 7% 6% 3 5% 5% 6% 8% 35%	74845
	Night	16% 9% 4 7% 6% 3 5% 5% 5% 7% 34%	75067
Transparency	Day	46% 6% 14% 22% 12% 1	74556
	Night	50% 5% 12% 20% 11% 1	74876
Seeing	Day	16% 9% 28% 26% 15% 6%	14104
	Night	19% 8% 28% 29% 14% 2	23849

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	16% 14% 5% 9% 8% 4 6% 5% 5% 6% 21%	1517
	11th to 20th	Day	18% 13% 7% 11% 9% 5% 5% 4 5% 6% 16%	1637
	21st to end	Day	16% 17% 7% 10% 7% 4 4 4 5% 5% 21%	1791
February	1st to 10th	Day	16% 16% 5% 9% 8% 4 5% 4 5% 5% 24%	1620
	11th to 20th	Day	15% 11% 7% 10% 9% 4 5% 4 4 6% 24%	1666
	21st to end	Day	18% 11% 4 9% 7% 3 5% 5% 5% 6% 28%	1480
March	1st to 10th	Day	16% 10% 6% 7% 7% 3 4 5% 6% 6% 30%	1876
	11th to 20th	Day	14% 11% 4 9% 6% 3 4 3 5% 7% 33%	1980
	21st to end	Day	19% 11% 5% 8% 7% 4 4 4 4 6% 28%	2178
April	1st to 10th	Day	13% 8% 5% 7% 6% 4 5% 6% 5% 7% 34%	2034
	11th to 20th	Day	16% 8% 4 6% 5% 3 5% 5% 5% 7% 35%	2309
	21st to end	Day	19% 7% 3 7% 5% 3 4 4 5% 7% 36%	2340
May	1st to 10th	Day	16% 7% 3 6% 6% 3 5% 5% 5% 8% 35%	2340
	11th to 20th	Day	17% 7% 3 6% 5% 4 5% 5% 5% 7% 35%	2301
	21st to end	Day	9% 5% 3 6% 5% 3 5% 6% 6% 10% 44%	2531
June	1st to 10th	Day	11% 6% 2 5% 6% 3 5% 6% 7% 10% 41%	2519
	11th to 20th	Day	9% 4 2 6% 5% 3 6% 6% 6% 9% 43%	2700
	21st to end	Day	9% 4 2 5% 5% 3 5% 5% 7% 11% 43%	2621
July	1st to 10th	Day	8% 5% 2 4 4 3 5% 5% 6% 8% 50%	2520
	11th to 20th	Day	9% 4 2 4 4 3 5% 5% 7% 10% 47%	2458
	21st to end	Day	8% 5% 3 4 5% 3 5% 6% 6% 9% 47%	2547
August	1st to 10th	Day	8% 4 2 4 5% 3 5% 5% 7% 10% 46%	2327
	11th to 20th	Day	8% 4 3 6% 6% 3 6% 6% 7% 10% 42%	2303
	21st to end	Day	9% 4 2 4 4 3 5% 6% 6% 10% 47%	2574
September	1st to 10th	Day	10% 6% 3 5% 5% 3 5% 5% 5% 9% 44%	2019
	11th to 20th	Day	9% 5% 2 5% 4 3 6% 6% 6% 8% 46%	1980
	21st to end	Day	17% 6% 2 4 4 4 3 5% 6% 8% 41%	1980
October	1st to 10th	Day	12% 5% 3 6% 6% 3 5% 6% 6% 6% 42%	1900
	11th to 20th	Day	17% 7% 3 7% 6% 4 4 5% 7% 7% 34%	1800
	21st to end	Day	20% 8% 3 6% 5% 3 6% 6% 6% 6% 31%	1892
November	1st to 10th	Day	11% 9% 3 6% 5% 3 5% 6% 6% 8% 39%	1672
	11th to 20th	Day	15% 11% 4 7% 5% 4 5% 5% 5% 7% 32%	1710
	21st to end	Day	19% 12% 6% 9% 5% 3 4 4 6% 7% 26%	1554
December	1st to 10th	Day	17% 12% 8% 12% 8% 3 6% 5% 5% 6% 19%	1520
	11th to 20th	Day	17% 14% 5% 9% 7% 3 5% 5% 6% 6% 23%	1910
	21st to end	Day	25% 18% 7% 11% 7% 3 4 3 4 5% 12%	2739
January	1st to 10th	Night	18% 13% 5% 8% 8% 4 5% 5% 4 5% 26%	2648
	11th to 20th	Night	19% 16% 6% 11% 6% 4 5% 4 5% 5% 20%	2538
	21st to end	Night	15% 15% 7% 9% 7% 3 4 4 5% 5% 24%	2599
February	1st to 10th	Night	17% 14% 6% 8% 7% 4 5% 4 5% 5% 24%	2340
	11th to 20th	Night	16% 12% 5% 9% 7% 3 4 5% 5% 6% 26%	2179
	21st to end	Night	21% 11% 5% 7% 6% 2 5% 5% 5% 4 29%	1776
March	1st to 10th	Night	16% 9% 4 7% 6% 3 6% 5% 5% 7% 33%	2083
	11th to 20th	Night	14% 7% 3 5% 5% 3 5% 5% 6% 8% 39%	1980
	21st to end	Night	18% 9% 4 7% 5% 3 4 5% 5% 5% 34%	2178
April	1st to 10th	Night	15% 9% 4 6% 6% 3 5% 4 5% 7% 37%	1940
	11th to 20th	Night	17% 7% 3 7% 5% 3 5% 5% 5% 8% 36%	1599
	21st to end	Night	17% 7% 3 6% 5% 3 4 5% 5% 6% 39%	1620
May	1st to 10th	Night	17% 7% 3 7% 6% 4 6% 6% 6% 6% 32%	1620
	11th to 20th	Night	18% 7% 3 5% 5% 3 4 5% 6% 7% 38%	1592
	21st to end	Night	9% 5% 3 5% 4 3 4 6% 6% 9% 47%	1744
June	1st to 10th	Night	12% 5% 2 5% 5% 3 5% 6% 6% 8% 44%	1425
	11th to 20th	Night	10% 5% 2 5% 5% 3 6% 6% 6% 7% 45%	1260
	21st to end	Night	9% 4 2 5% 5% 3 5% 4 6% 9% 47%	1332
July	1st to 10th	Night	8% 4 2 5% 5% 3 4 4 6% 8% 51%	1440
	11th to 20th	Night	9% 4 2 5% 4 2 4 5% 6% 9% 50%	1500
	21st to end	Night	6% 3 2 4 5% 3 5% 5% 7% 10% 50%	1771
August	1st to 10th	Night	7% 4 2 5% 4 3 5% 5% 6% 9% 50%	1611
	11th to 20th	Night	8% 4 2 5% 5% 3 5% 6% 6% 9% 47%	1598
	21st to end	Night	8% 4 2 4 5% 3 4 5% 5% 7% 52%	1782
September	1st to 10th	Night	10% 5% 2 5% 5% 3 5% 5% 6% 8% 47%	1917
	11th to 20th	Night	10% 4 2 5% 5% 4 4 4 5% 7% 51%	1980
	21st to end	Night	15% 5% 3 5% 4 3 5% 4 5% 7% 44%	1980
October	1st to 10th	Night	14% 5% 2 5% 4 3 5% 4 5% 8% 45%	2059
	11th to 20th	Night	17% 8% 3 7% 6% 3 5% 3 6% 7% 34%	2160
	21st to end	Night	21% 8% 3 6% 6% 3 5% 4 5% 6% 33%	2461
November	1st to 10th	Night	13% 8% 2 5% 6% 3 4 5% 6% 7% 42%	2406
	11th to 20th	Night	17% 11% 4 7% 7% 3 5% 4 5% 7% 31%	2470
	21st to end	Night	21% 12% 5% 6% 6% 3 4 4 5% 6% 28%	2622
December	1st to 10th	Night	19% 14% 6% 8% 6% 4 6% 6% 5% 7% 20%	2660
	11th to 20th	Night	16% 13% 6% 8% 7% 4 6% 5% 5% 6% 25%	3285
	21st to end	Night	27% 20% 7% 9% 6% 3 4 4 4 5% 12%	4912

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	64% 6% 12% 13% 5% 1	1518
	11th to 20th	Day	68% 6% 13% 10% 2	1637
	21st to end	Day	64% 5% 11% 13% 6%	1791
February	1st to 10th	Day	62% 5% 11% 15% 7%	1620
	11th to 20th	Day	60% 5% 11% 17% 7% 1	1675
	21st to end	Day	56% 5% 13% 18% 7% 2	1480
March	1st to 10th	Day	52% 6% 14% 20% 7% 1	1876
	11th to 20th	Day	50% 5% 12% 20% 12% 2	1980
	21st to end	Day	55% 5% 10% 22% 7% 1	2178
April	1st to 10th	Day	46% 6% 14% 19% 14% 1	2034
	11th to 20th	Day	46% 5% 13% 20% 13% 2	2309
	21st to end	Day	47% 4 13% 22% 11% 3	2340
May	1st to 10th	Day	45% 6% 11% 24% 11% 2	2340
	11th to 20th	Day	46% 8% 13% 17% 15% 2	2305
	21st to end	Day	34% 7% 15% 26% 15% 2	2531
June	1st to 10th	Day	37% 6% 14% 29% 13% 2	2519
	11th to 20th	Day	34% 8% 17% 23% 16% 2	2700
	21st to end	Day	32% 9% 15% 26% 16% 3	2621
July	1st to 10th	Day	32% 6% 11% 28% 20% 3	2451
	11th to 20th	Day	30% 6% 15% 30% 18% 2	2383
	21st to end	Day	32% 7% 15% 25% 18% 3	2405
August	1st to 10th	Day	30% 6% 17% 33% 13% 1	2314
	11th to 20th	Day	34% 7% 16% 28% 13% 1	2303
	21st to end	Day	31% 7% 14% 27% 19% 2	2574
September	1st to 10th	Day	35% 7% 18% 24% 15% 2	2019
	11th to 20th	Day	33% 6% 14% 30% 15% 1	1980
	21st to end	Day	40% 7% 13% 25% 14% 1	1980
October	1st to 10th	Day	41% 6% 14% 24% 14% 1	1900
	11th to 20th	Day	48% 6% 14% 21% 10% 1	1800
	21st to end	Day	53% 7% 14% 18% 8% 1	1892
November	1st to 10th	Day	44% 7% 13% 22% 13% 1	1672
	11th to 20th	Day	53% 4 15% 18% 10% 1	1710
	21st to end	Day	57% 5% 15% 18% 5%	1554
December	1st to 10th	Day	66% 5% 13% 12% 4	1520
	11th to 20th	Day	61% 6% 13% 16% 4	1906
	21st to end	Day	75% 4 10% 8% 2	2739
January	1st to 10th	Night	62% 4 11% 16% 7%	2648
	11th to 20th	Night	68% 5% 12% 12% 3	2538
	21st to end	Night	63% 4 11% 15% 6%	2599
February	1st to 10th	Night	62% 5% 11% 15% 5% 1	2340
	11th to 20th	Night	58% 5% 11% 17% 8% 1	2181
	21st to end	Night	57% 3 11% 19% 8% 1	1776
March	1st to 10th	Night	50% 4 13% 23% 9% 1	2083
	11th to 20th	Night	43% 6% 12% 22% 14% 3	1980
	21st to end	Night	52% 4 8% 23% 11% 2	2178
April	1st to 10th	Night	48% 4 12% 20% 14% 2	1940
	11th to 20th	Night	46% 5% 11% 19% 17% 3	1599
	21st to end	Night	45% 4 10% 21% 16% 4	1620
May	1st to 10th	Night	51% 6% 11% 18% 11% 3	1620
	11th to 20th	Night	46% 5% 9% 20% 17% 3	1593
	21st to end	Night	34% 7% 13% 28% 17% 2	1745
June	1st to 10th	Night	37% 6% 11% 26% 17% 3	1425
	11th to 20th	Night	37% 6% 14% 24% 16% 3	1260
	21st to end	Night	34% 7% 11% 27% 21% 1	1332
July	1st to 10th	Night	31% 6% 11% 27% 22% 3	1400
	11th to 20th	Night	30% 7% 13% 30% 18% 3	1452
	21st to end	Night	28% 6% 18% 24% 20% 4	1672
August	1st to 10th	Night	29% 6% 14% 33% 15% 1	1600
	11th to 20th	Night	32% 9% 13% 30% 13% 2	1598
	21st to end	Night	30% 7% 13% 29% 19% 2	1782
September	1st to 10th	Night	35% 7% 14% 26% 15% 4	1917
	11th to 20th	Night	33% 5% 12% 28% 20% 1	1980
	21st to end	Night	41% 5% 12% 23% 17% 1	1980
October	1st to 10th	Night	39% 6% 13% 21% 20% 1	2059
	11th to 20th	Night	51% 5% 11% 18% 14% 1	2160
	21st to end	Night	54% 5% 11% 20% 9% 1	2461
November	1st to 10th	Night	44% 4 13% 22% 15% 1	2406
	11th to 20th	Night	56% 4 13% 18% 9% 1	2470
	21st to end	Night	59% 4 13% 19% 5%	2622
December	1st to 10th	Night	69% 4 10% 13% 4	2660
	11th to 20th	Night	61% 5% 14% 15% 4	3288
	21st to end	Night	77% 4 10% 8% 2	4912

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% 14% 37% 17% 7% 1	270
	11th to 20th	Day	23% 16% 41% 15% 5% 1	270
	21st to end	Day	26% 12% 32% 24% 6%	267
February	1st to 10th	Day	27% 15% 35% 22% 1	240
	11th to 20th	Day	23% 17% 39% 18% 3	240
	21st to end	Day	22% 20% 40% 17% 2	198
March	1st to 10th	Day	24% 15% 34% 22% 5%	316
	11th to 20th	Day	22% 14% 32% 24% 7% 2	420
	21st to end	Day	25% 13% 30% 26% 6%	462
April	1st to 10th	Day	16% 10% 38% 26% 8% 2	420
	11th to 20th	Day	22% 12% 30% 21% 9% 5%	412
	21st to end	Day	21% 12% 34% 20% 11% 3	420
May	1st to 10th	Day	25% 9% 29% 22% 12% 3	423
	11th to 20th	Day	18% 8% 29% 26% 13% 6%	447
	21st to end	Day	12% 5% 22% 32% 21% 7%	485
June	1st to 10th	Day	12% 5% 29% 36% 15% 4	495
	11th to 20th	Day	11% 5% 27% 36% 18% 2	630
	21st to end	Day	11% 4 28% 35% 16% 5%	630
July	1st to 10th	Day	10% 3 20% 30% 26% 11%	621
	11th to 20th	Day	11% 4 20% 34% 21% 10%	556
	21st to end	Day	9% 4 19% 30% 30% 8%	488
August	1st to 10th	Day	8% 2 16% 30% 27% 17%	446
	11th to 20th	Day	10% 3 15% 29% 30% 12%	439
	21st to end	Day	9% 3 19% 27% 28% 14%	495
September	1st to 10th	Day	10% 3 22% 30% 23% 12%	450
	11th to 20th	Day	8% 3 16% 27% 32% 13%	450
	21st to end	Day	19% 6% 22% 26% 19% 9%	450
October	1st to 10th	Day	13% 8% 24% 26% 21% 8%	450
	11th to 20th	Day	17% 12% 33% 27% 9% 2	450
	21st to end	Day	25% 15% 34% 19% 6% 1	407
November	1st to 10th	Day	14% 15% 33% 23% 13% 3	270
	11th to 20th	Day	16% 21% 30% 23% 7% 2	270
	21st to end	Day	23% 10% 42% 22% 2	196
December	1st to 10th	Day	21% 15% 39% 18% 6% 1	180
	11th to 20th	Day	23% 15% 38% 18% 6%	180
	21st to end	Day	23% 16% 39% 17% 4	261
January	1st to 10th	Night	24% 11% 38% 20% 6% 1	950
	11th to 20th	Night	28% 12% 34% 21% 4	828
	21st to end	Night	20% 10% 37% 27% 6%	800
February	1st to 10th	Night	28% 9% 36% 25% 3	720
	11th to 20th	Night	23% 11% 33% 26% 6%	703
	21st to end	Night	26% 11% 40% 21% 2	592
March	1st to 10th	Night	21% 8% 37% 27% 7%	720
	11th to 20th	Night	18% 9% 38% 28% 6% 1	720
	21st to end	Night	22% 9% 31% 28% 10% 1	792
April	1st to 10th	Night	19% 10% 35% 31% 5%	680
	11th to 20th	Night	20% 8% 35% 28% 8% 2	533
	21st to end	Night	19% 6% 34% 30% 11%	540
May	1st to 10th	Night	20% 4 30% 34% 10% 2	540
	11th to 20th	Night	20% 5% 23% 35% 15% 2	531
	21st to end	Night	11% 3 21% 35% 27% 3	584
June	1st to 10th	Night	12% 3 27% 40% 17% 1	396
	11th to 20th	Night	11% 2 21% 43% 22%	360
	21st to end	Night	10% 5% 20% 45% 17% 2	432
July	1st to 10th	Night	9% 2 13% 39% 32% 5%	525
	11th to 20th	Night	9% 2 15% 40% 28% 5%	522
	21st to end	Night	6% 2 15% 45% 29% 3	591
August	1st to 10th	Night	9% 1 12% 42% 29% 7%	537
	11th to 20th	Night	8% 1 13% 39% 33% 5%	534
	21st to end	Night	10% 2 13% 39% 31% 6%	594
September	1st to 10th	Night	12% 4 15% 34% 30% 6%	685
	11th to 20th	Night	11% 4 17% 31% 30% 7%	720
	21st to end	Night	16% 6% 19% 31% 22% 6%	720
October	1st to 10th	Night	16% 4 24% 31% 21% 4	720
	11th to 20th	Night	20% 11% 31% 25% 12% 2	720
	21st to end	Night	23% 13% 30% 28% 5%	792
November	1st to 10th	Night	18% 10% 29% 29% 13% 2	740
	11th to 20th	Night	22% 13% 35% 21% 8% 1	760
	21st to end	Night	28% 11% 32% 21% 8%	760
December	1st to 10th	Night	24% 14% 35% 20% 7% 1	760
	11th to 20th	Night	24% 11% 37% 23% 4	760
	21st to end	Night	28% 11% 33% 24% 3	988

Page generated at 2024-01-19 09:28:35. Version ac07

Copyright 2024 Attilla Danko