id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
1176172498,I_kwDOAMm_X85GGvfS,6399,DataArray.plot.pcolormesh with kwarg shading='gouraud',9312831,closed,0,,,4,2022-03-22T02:09:36Z,2022-03-22T10:14:18Z,2022-03-22T10:14:18Z,NONE,,,,"### What happened?

Given a DataArray `da`, I try to plot with
```python
da.plot.pcolormesh(shading='flat')
```
and it works well.  But if I change shading to 'gouraud', it reports
``` python
C:\ProgramData\Anaconda3\lib\site-packages\matplotlib\axes\_axes.py in _pcolorargs(self, funcname, shading, *args, **kwargs)
   5709         else:    # ['nearest', 'gouraud']:
   5710             if (Nx, Ny) != (ncols, nrows):
-> 5711                 raise TypeError('Dimensions of C %s are incompatible with'
   5712                                 ' X (%d) and/or Y (%d); see help(%s)' % (
   5713                                     C.shape, Nx, Ny, funcname))

TypeError: Dimensions of C (256, 512) are incompatible with X (513) and/or Y (257); see help(pcolormesh)
```

Not sure if this relates to `xarray` or `matplotlib`.

### What did you expect to happen?

```python
da.plot.pcolormesh(shading='gouraud')
```
should works well as
```python
da.plot.pcolormesh(shading='flat')
```

### Minimal Complete Verifiable Example

```Python
import xarray as xr

ds = xr.tutorial.open_dataset('air_temperature')
ds.air[0].plot.pcolormesh(shading='gouraud')
```


### Relevant log output

```Python
C:\ProgramData\Anaconda3\lib\site-packages\matplotlib\axes\_axes.py in _pcolorargs(self, funcname, shading, *args, **kwargs)
   5709         else:    # ['nearest', 'gouraud']:
   5710             if (Nx, Ny) != (ncols, nrows):
-> 5711                 raise TypeError('Dimensions of C %s are incompatible with'
   5712                                 ' X (%d) and/or Y (%d); see help(%s)' % (
   5713                                     C.shape, Nx, Ny, funcname))

TypeError: Dimensions of C (25, 53) are incompatible with X (54) and/or Y (26); see help(pcolormesh)
```


### Anything else we need to know?

No

### Environment

INSTALLED VERSIONS
------------------
commit: None
python: 3.8.11 (default, Aug  6 2021, 09:57:55) [MSC v.1916 64 bit (AMD64)]
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 60 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: ('Chinese (Simplified)_China', '936')
libhdf5: 1.12.1
libnetcdf: 4.8.1

xarray: 0.19.0
pandas: 1.3.1
numpy: 1.20.3
scipy: 1.6.2
netCDF4: 1.5.8
pydap: installed
h5netcdf: 0.12.0
h5py: 3.4.0
Nio: None
zarr: 2.8.1
cftime: 1.6.0
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: 0.9.9.1
iris: None
bottleneck: 1.3.2
dask: 2021.08.0
distributed: 2021.08.0
matplotlib: 3.4.2
cartopy: 0.18.0
seaborn: 0.11.2
numbagg: None
pint: None
setuptools: 52.0.0.post20210125
pip: 21.0.1
conda: 4.11.0
pytest: 6.2.4
IPython: 7.26.0
sphinx: 4.0.2","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6399/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue
588126763,MDU6SXNzdWU1ODgxMjY3NjM=,3896,consecutive time selection,9312831,closed,0,,,7,2020-03-26T03:24:12Z,2020-03-28T14:39:06Z,2020-03-28T14:39:06Z,NONE,,,,"Not sure if this has been asked.

I have a sea surface temperature (SST) `DataArray` (monthly data) and want to use it to define El Nino.  An El Nino event is defined by a five consecutive 3-month running mean of SST anomalies in the Niño 3.4 region that is above the threshold of 0.5°C.  I know I can use `roll` object to get the 3-month running mean.  But how to meet the requirement of five-consecutive months?  Is there a simple way to do this using xarray's API?","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3896/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue